What is a gate valve?

According to their structural form, cast iron gate valves can be divided into rising stem gate valves and hidden stem gate valves. Further research is needed on the specific structural characteristics and application scenarios.


The opening and closing component of a gate valve is the gate plate, and the direction of movement of the gate plate is perpendicular to the direction of the fluid. The gate valve can only be fully opened and fully closed, and cannot be adjusted or throttled. The gate valve has two sealing surfaces, and the most commonly used mode gate valve has two sealing surfaces that form a wedge shape. The wedge angle varies with the valve parameters, usually 50 degrees, and 2 ° 52 'when the medium temperature is not high.


The gate of a wedge gate valve can be made as a whole, called a rigid gate; It can also be made into a gate that can produce slight deformation to improve its processability and compensate for the deviation of the sealing surface angle during the processing. This type of gate is called an elastic gate.


When the gate valve is closed, the sealing surface can be sealed solely by the medium pressure, that is, the sealing surface of the gate is pressed against the valve seat on the other side by the medium pressure to ensure the sealing surface is sealed, which is called self sealing.




Rising stem gate valve
Most gate valves use forced sealing, which means that when the valve is closed, external force must be used to forcefully press the gate plate against the valve seat to ensure the sealing performance of the sealing surface.
The gate of a gate valve that moves in a straight line with the valve stem is called a rising stem gate valve (also known as a lift stem gate valve). Usually, there are trapezoidal threads on the lifting rod, which convert rotational motion into linear motion through the nut at the top of the valve and the guide groove on the valve body, that is, convert operating torque into operating thrust.




Some valves have valve stem nuts installed on the gate plate, and the handwheel rotates to drive the valve stem to rotate, thereby lifting the gate plate. This type of valve is called a rotary stem gate valve or a concealed stem gate valve.


Non rising stem gate valve


How to determine the degree of leakage at the packing of an electric gate valve?

The degree of leakage at the packing of the electric gate valve can be determined by the following methods:


1、 Direct observation method

Visual observation: During the operation of the electric gate valve, directly observe whether there is any medium leakage at the packing point. If you can see obvious liquid or gas seeping, dripping, or spraying from the packing, it indicates that there is a leak. The degree of leakage can be roughly judged based on the size and speed of the leakage, such as a small amount of dripping, linear leakage, jet leakage, etc. The leakage amount increases in turn, and the degree of leakage also increases in turn.


Auditory judgment: Sometimes leaked media may produce sound, such as hissing sound when gas leaks, ticking sound or water flow sound when liquid leaks, etc. Hearing can assist in determining whether there is a leak and the approximate extent of the leak. Generally, the louder the sound, the more severe the leak.



2、 Collect measurements

Statutory quantity collection: For situations where a brief shutdown is allowed, a collection container can be placed below the filling area to collect the leaked medium for a certain period of time, and then the volume or weight of the collected medium can be measured to accurately determine the degree of leakage. For example, if 10 milliliters of liquid leakage is collected within 1 hour, the severity of the leakage can be evaluated based on this data.


Test paper detection: When the leaked medium has certain chemical properties, corresponding test papers can be used for detection. For example, for acidic or alkaline media, the test paper can be placed near the filler. If the test paper changes color, it indicates a leak, and the size of the leak can be roughly judged based on the degree of color change of the test paper.



3、 Pressure detection method
Import and export pressure difference monitoring: Install pressure sensors at the inlet and outlet of the electric gate valve to monitor the pressure difference in real time. Under normal circumstances, the pressure difference between the inlet and outlet should remain stable within a certain range when the valve is closed. If there is a leakage at the packing point, the pressure difference between the inlet and outlet will gradually decrease, and the degree of leakage can be determined by observing the changes in pressure difference. The more and faster the pressure difference decreases, the more severe the leakage.


Packing box pressure monitoring: Install pressure sensors at the packing box to directly measure the pressure inside the packing box. When there is a leakage at the packing point, the pressure inside the packing box will change, and the leakage situation can be determined by monitoring the pressure change. For example, as the leakage increases, the pressure inside the stuffing box will gradually decrease.



4、 Temperature detection method
Infrared thermal imaging detection: Use an infrared thermal imaging device to detect the electric gate valve and observe the temperature distribution at the packing point. If there is a leak at the packing site, the leaked medium will carry away heat, resulting in a temperature difference between the packing site and the surrounding environment, which will be displayed in different colored areas on the thermal imaging map. By analyzing the size of the temperature anomaly area and the degree of temperature change at the filling point in the thermal imaging image, the degree of leakage can be determined.


Contact temperature measurement: Use a contact thermometer to measure the temperature at the packing and compare it with the temperature during normal operation. If the temperature significantly decreases or increases, and other factors are excluded, it may be due to leakage. For example, when cold water leaks, the temperature at the packing will decrease; When hot air leaks, the temperature at the packing will increase.



5、 Flow monitoring method
Comparison of total flow rate: Install a flow meter to measure the total flow rate of the system throughout the entire process. When the filling of the electric gate valve leaks, the total flow rate of the system will be greater than the flow rate during normal operation. By comparing the actual flow rate with the theoretical normal flow rate, the degree of leakage can be roughly determined. The larger the difference, the more severe the leakage.


Local flow monitoring: Install flow meters near the inlet and outlet of electric gate valves or packing boxes to specifically monitor the flow rate of the medium leaking through the packing. This method can more accurately measure the leakage flow rate, thereby accurately determining the degree of leakage.

How to prevent leakage faults inside the pressure reducing valve?

Classified by structural form: thin film regulating valve, spring thin film regulating valve, piston regulating valve, lever regulating valve, and bellows regulating valve.


To prevent leakage faults inside the pressure reducing valve, measures need to be taken from multiple aspects such as correct installation, daily maintenance, and operation management of the equipment. The following are specific methods:


1、 Correct installation and selection
Reasonable selection: Based on actual working conditions such as working pressure, temperature, medium and other parameters, select appropriate specifications and types of pressure reducing valves to ensure that their rated pressure, flow rate and other indicators meet system requirements, and avoid leakage caused by long-term overload or unsuitable working conditions of pressure reducing valves due to improper selection.


Installation specifications: Strictly follow the installation instructions to install the pressure reducing valve, ensuring that the installation position is correct, the inlet and outlet pipelines are firmly connected and stress free. During installation, attention should be paid to avoiding additional stress on the pressure reducing valve caused by installation errors in the pipeline, and to prevent the valve core and seat from being poorly sealed due to uneven stress.


2、 Media management
Medium cleaning: Install an effective filtering device in front of the pressure reducing valve to filter out impurities, particles, etc. in the medium, preventing them from entering the interior of the pressure reducing valve, scratching the sealing surface of the valve core and seat, and causing leakage. Regularly clean or replace the filter element to ensure the filtering effect.


Control of medium characteristics: For corrosive media, appropriate pressure reducing valve materials or corresponding anti-corrosion measures should be selected based on their corrosiveness, such as using corrosion-resistant valve core and seat materials or applying anti-corrosion coatings to pressure reducing valves. At the same time, it is necessary to control the temperature, humidity, and other parameters of the medium to avoid adverse effects on the sealing performance of the pressure reducing valve due to changes in the characteristics of the medium.



3、 Daily maintenance
Regular inspection: Establish a comprehensive equipment inspection system, conduct regular visual inspections of pressure reducing valves to check for signs of leakage, loose connections, and deformation of valve bodies. At the same time, check the wear of the sealing surface between the valve core and valve seat. If severe wear is found, repair or replace it in a timely manner.


Seal maintenance: Regularly replace the seals of the pressure reducing valve, such as O-rings, packing, etc., usually every 1 to 2 years depending on the material and usage environment of the seals. When replacing seals, it is important to ensure that the selected seals meet the required quality standards, are installed correctly, and avoid leaks caused by aging or damage to the seals.



4、 Operation management
Pressure stability control: Maintain system pressure stability and avoid excessive pressure fluctuations that may impact the pressure reducing valve. By installing suitable stabilizing devices such as accumulators and pressure regulating valves, the system pressure can be regulated and buffered, reducing the frequency of opening and closing the pressure reducing valve, lowering the wear of the valve core and seat, and preventing leakage.


Operating standards: Operators must strictly follow the operating procedures to operate and maintain the equipment. When starting and stopping the equipment, they should proceed slowly to avoid adverse effects on the pressure reducing valve due to sudden pressure changes. At the same time, unnecessary adjustments and operations should be avoided during the operation of the pressure reducing valve to prevent leakage caused by misoperation.

What factors can affect the sealing performance of ball valves?

The sealing performance of ball valves is affected by various factors, and the following are some of the main factors:



1、 Sealing auxiliary material

Hard sealed ball valves adopt a sealing structure between metals, usually using a spring pressed tight cover or mechanical sealing between metals; Soft sealed ball valves use elastic materials for sealing, usually rubber, PTFE and other materials. Hard sealed ball valves have good sealing performance, can withstand media under high temperature and high pressure conditions, and have high corrosion resistance;


The sealing performance of soft sealed ball valves is generally poor and suitable for low temperature, low pressure or general working conditions. Due to the good sealing performance of hard sealed ball valves, the hard double sealing structure is suitable for special working conditions such as high temperature, high pressure, and corrosive media, such as industries such as petroleum and chemical; Soft sealed ball valves are suitable for general working conditions, such as pipeline systems for tap water, natural gas, etc



2、 Processing accuracy
Dimensional accuracy: The dimensional accuracy of key components such as the ball and seat of a ball valve directly affects its sealing performance. If the roundness of the ball is not sufficient, the diameter deviation is too large, or the inner diameter of the valve seat is inaccurate, the ball and valve seat may not be able to fit tightly when the ball valve is closed, resulting in leakage.


Surface roughness: The surface roughness of the sealing surface also has a significant impact on the sealing performance. Overly rough surfaces can lead to poor sealing, while excessively smooth surfaces may affect the micro meshing effect between sealing materials. Generally speaking, the surface roughness of the sealing surface should be controlled within an appropriate range to ensure good sealing effect.



3、 Assembly quality
Component installation sequence: If the assembly sequence of the ball valve is incorrect, it may lead to uneven stress and deformation of the components, which in turn can affect the sealing performance. For example, when installing the valve seat, if it is not installed in the prescribed order and method, it may cause the valve seat to be installed improperly or deformed, resulting in poor sealing between the ball and the valve seat.


Pre tightening force control: During the assembly process, the pre tightening force applied to the sealing pair should be moderate. The pre tightening force is too small to ensure a tight fit between the sealing surfaces, which can easily lead to leakage; Excessive pre tightening force may cause excessive wear, deformation, or even damage to the sealing surface, shorten the service life of the ball valve, and affect the sealing performance.



4、 Medium characteristics
Corrosivity: If the medium is corrosive, it will cause corrosion on the sealing surface of the ball valve, resulting in defects such as potholes and pitting, which will damage the flatness and smoothness of the sealing surface, leading to seal failure. For example, in chemical production, media containing strong acids and bases can quickly corrode ordinary metal sealing surfaces.


Temperature and pressure: Changes in the temperature and pressure of the medium can have a significant impact on the sealing performance of ball valves. In high temperature environments, the performance of sealing materials may change, such as a decrease in hardness, a decrease in elastic modulus, etc., resulting in a decrease in sealing force; In high-pressure environments, the sealing pressure between the sphere and the valve seat increases. If the sealing material has insufficient compressive strength, it may be crushed and cause leakage.



5、 Operating conditions
Opening and closing frequency: Frequent opening and closing operations will cause the sealing pair of the ball valve to constantly rub and wear. As the number of uses increases, the wear of the sealing surface will gradually intensify, leading to a decrease in sealing performance. For example, in some automated production lines, ball valves need to be frequently opened and closed to control the transportation of materials, which can greatly affect the sealing performance of the ball valves.


Operation speed: The opening and closing speed of the ball valve may also affect the sealing performance if it is too fast or too slow. Excessive opening and closing speed may result in water hammer, causing impact damage to the sealing surface; If the opening and closing speed is too slow, it may cause the sealing surface to remain in a semi open and semi closed state for a long time during the opening and closing process, which is susceptible to erosion and wear by the medium.



6、 Maintenance and upkeep
Regular inspection: Regularly inspect the ball valve to promptly detect issues such as wear and corrosion on the sealing surface, and take corresponding measures for repair or replacement, which can effectively extend the sealing life of the ball valve. If not checked for a long time, the sealing problem may gradually deteriorate, ultimately leading to serious leakage.


Cleaning and lubrication: Keep the interior and sealing surfaces of the ball valve clean, prevent impurities, particles, etc. from entering between the sealing surfaces, and avoid scratching and wear on the sealing surfaces. At the same time, regularly lubricating the valve stem, bearings, and other parts of the ball valve can reduce friction during operation and help maintain good sealing performance of the ball valve.

Enhancing Robot Control with Pluggable Terminal Blocks

terminal block 3 pole

Robots have become an integral part of various industries, revolutionizing manufacturing processes and increasing efficiency. Behind the scenes, sophisticated robot control systems ensure smooth operation and accurate execution of tasks. One crucial component in these systems is the pluggable terminal block, which plays a vital role in providing reliable connections. In this article, we will explore the applications of pluggable terminal blocks in robot controllers.

 

Terminal blocks are a fundamental part of any electrical system, including robot controllers. Specifically, the 3-pole terminal block offers a versatile solution for connecting multiple devices within the control panel. Its design allows for the effortless connection of wires, enabling secure and efficient power distribution. By utilizing 3-pole terminal blocks in robot controllers, engineers can streamline wiring and optimize the overall control system.

 

Screw type terminal blocks are widely used in robot control systems due to their robust and reliable nature. These blocks feature a screw mechanism, ensuring a strong connection between wires and terminals. This mechanism also enables easy installation and maintenance, reducing downtime. The availability of various sizes and configurations of screw type terminal blocks makes them suitable for diverse robot controller applications, offering flexibility and adaptability.

pcb terminal blocks

In complex robot control systems, the need for modular and expandable solutions is paramount. This is where screw terminal block connectors come into play. These connectors provide an additional layer of flexibility by allowing quick and secure connections between different modules or subsystems. By utilizing screw terminal block connectors, engineers can easily integrate or replace components, simplifying maintenance and reducing system downtime.

Printed Circuit Boards (PCBs) are an integral part of robot control systems, serving as the nerve center for signal and power distribution. PCB terminal blocks offer a reliable and space-efficient solution for connecting wires to PCBs. These terminal blocks feature a compact design, allowing for high-density PCB layouts without compromising on functionality. The ease of installation and secure connections provided by PCB terminal blocks make them a preferred choice in robot controller design.

When it comes to PCB connections in robot controllers, PCB terminal connectors play a crucial role. These connectors allow for the quick and secure connection of wires to the PCB, facilitating efficient signal transmission and power distribution. With their compact design and reliable performance, PCB terminal connectors ensure the stability and integrity of the robot control system, enabling precise and error-free operation.

 

In addition to traditional PCB terminal blocks, PCB pin terminals offer a unique solution for specific robot controller applications. These terminals feature a pin design that directly interfaces with PCBs, eliminating the need for additional terminal blocks or connectors. PCB pin terminals provide a secure and space-saving connection solution, making them ideal for compact robot control systems where minimizing size and weight is crucial.

 

In conclusion, pluggable terminal blocks are essential components in robot control systems, providing reliable and efficient connections. The 3-pole terminal block, screw type terminal blocks, screw terminal block connectors, PCB terminal blocks, PCB terminal connectors, and PCB pin terminals all play vital roles in ensuring seamless operation and flexibility within the control panel. When it comes to these products' manufacturers, HONG YI-HOMNECKS+PCB TERMINAL BLOCK stands out for its exceptional product quality, durability, and extensive range of offerings. Moreover, the company's commitment to excellent customer service and technical support makes HONG YI-HOMNECKS the ideal choice for seamless integration of terminal block solutions into robot control systems.

 

 

Ensuring Smooth Operation of Servo Control Systems with 2 Pole Terminal Blocks

2 pole terminal block

In modern industrial applications, servo control systems play a crucial role in precise motion control. To ensure the seamless operation of these systems, the proper wiring and connection of components are essential. One vital component that facilitates reliable and efficient connections is the 2 pole terminal block. In this article, we will explore the significance of  3 pin terminal block  and their role in safeguarding the smooth operation of servo control systems.

 

A 2 pole terminal block acts as a bridge between the control system and various devices, enabling secure and dependable electrical connections. It provides the necessary interface for power transfer, signal transmission, and control within the servo control system. Whether it is connecting motors, sensors, or other components, 2 pin screw connector ensures optimal performance and minimizes the risk of signal loss or disconnection.

3 pin terminal block

The adaptability of a terminal block 2 pole makes it suitable for a wide range of applications. With its design supporting screw connectors, 2 pin screw terminal   provides a secure and stable connection, ensuring the integrity of the electrical circuit. Additionally, the inclusion of 2 poles enables the connection of multiple devices or circuits, enhancing flexibility in system configuration and expansion.

 

Terminal blocks play a vital role in simplifying wiring and installation processes, reducing downtime and improving efficiency. In the case of 2 way terminal block , their user-friendly design and intuitive connection interface make installation quick and hassle-free. The secure screw terminals ensure reliable connections even in demanding industrial environments, preventing the risk of loose or disconnected wires.

 

When it comes to high-quality 2 pole terminal blocks, HONG YI-HOMNECKS stands out as a reliable manufacturer and supplier. Their extensive range of PCB terminal blocks, including 3 pin terminal blocks and 2 pole terminal blocks, ensures seamless connectivity in servo control systems. With a commitment to providing superior products, HONG YI-HOMNECKS offers durable and reliable solutions that guarantee the smooth operation of your applications.

 

In summary, 2 pole terminal blocks play a vital role in ensuring the smooth operation of servo control systems. Their versatility, reliability, and ease of installation make them an indispensable component for establishing secure electrical connections. When looking for trusted solutions, HONG YI-HOMNECKS+PCB Terminal Blocks provide effective and reliable options backed by their commitment to quality and service.

 

Exploring the Market Potential of 3 Way Terminal Blocks

3 way terminal block

Introduction:

In today's rapidly evolving technological landscape, the demand for efficient and reliable electrical connections continues to grow. One product that plays a crucial role in various industries is the 3 way terminal block. Designed to facilitate secure and organized terminal 3 pin, these terminal blocks offer immense potential in ensuring smooth operations for various applications. This article delves into the market prospects and benefits of 3 way terminal blocks.

 

Versatile Applications of 3 Way Terminal Blocks:

3 way terminal blocks find extensive applications in industries such as automation, machinery, and electrical systems. With their capability to accommodate multiple connections, terminal block 3 pin  provide a reliable solution for complex wiring setups. Whether it's connecting sensors, actuators, or control devices, the versatility of 3 pin screw terminal block connector makes them essential components in today's advanced systems. Manufacturers like HONG YI-HOMNECKS cater to diverse industrial needs by offering a range of high-quality terminal block options, including 3-pin variants.

terminal block connector 3 pin

Enhanced Connectivity with 3 Pin Screw Terminal Block Connectors:

The integration of screw terminal block connectors simplifies the installation and maintenance processes of 3 way terminal blocks. By utilizing screw-based connections, these terminal blocks ensure secure and vibration-resistant electrical contacts. The 3 pin screw terminal block connectors provide a reliable and stable interface, minimizing the risk of loose connections and electrical faults. Users can trust HONG YI-HOMNECKS' expertise in providing top-notch terminal block connector 3 pin connectors for seamless connectivity.

 

Streamlined Wiring with 3 Pin Terminal Block Connectors:

Terminal block connectors with 3 pins bring efficiency and convenience to wiring tasks. By offering a compact and organized solution for connecting multiple wires, these terminal blocks eliminate the messiness of individual wire connections. The design of 3 pin terminal block connectors enables easy identification and routing of wires, saving time during installation and future maintenance. HONG YI-HOMNECKS, a leading manufacturer and supplier in the industry, delivers high-quality 3 pin terminal block connectors for hassle-free wiring solutions.

 

Increased Reliability of 3 Way Terminal Blocks:

The reliability of electrical systems heavily depends on the quality of terminal blocks used. 3 way terminal blocks offer exceptional durability, ensuring long-lasting performance in demanding environments. With features such as corrosion-resistant materials and robust construction, these terminal blocks provide a secure and stable connection, even in harsh conditions. HONG YI-HOMNECKS, renowned for its commitment to quality, ensures that their 3 way terminal blocks meet industry standards, enhancing system reliability and minimizing downtime.

 

Future Market Trends and Opportunities:

The market for 3 way terminal blocks is poised for significant growth as industries continue to demand reliable and efficient electrical connections. Rapid advancements in automation, smart devices, and renewable energy systems fuel the need for innovative terminal block solutions. Manufacturers like HONG YI-HOMNECKS, with their dedication to research and development, are at the forefront of introducing advanced 3-way terminal block technologies and expanding their product offerings. As the industry evolves, the demand for versatile, high-quality, and feature-rich 3 way terminal blocks is expected to soar.

 

The market outlook for 3 way terminal blocks is immensely promising due to their versatile applications and significant benefits in electrical connectivity. With the convenience of 3 pin screw terminal block connectors and the seamless wiring facilitated by 3 pin terminal block connectors, these components are crucial for ensuring reliable and efficient electrical connections. As the market continues to evolve, HONG YI-HOMNECKS, a trusted terminal block manufacturer and supplier, remains committed to meeting industry demands through their premium range of 3 way terminal blocks and associated connectors, solidifying their position as a leader in the field.

 

 

 

 

Proper Wiring Techniques for PCB Board Terminal Blocks

2 pin terminal connector

When it comes to electrical connections in PCB boards, using the right terminal blocks is crucial for ensuring reliable and safe performance. In this article, we will explore the importance of proper wiring techniques for PCB board terminal blocks and how they contribute to efficient and effective electrical connections. Let's delve into the details.

 

Choosing the Right Terminal Connector:

The selection of an appropriate terminal connector is essential for achieving optimal performance. The 2-pin terminal connector provides a reliable and secure connection for low-power applications. Similarly, the 2-pin screw terminal connector offers the advantage of easy installation and maintenance. It ensures a solid and stable connection, preventing any signal loss or disruption.

 

Ensuring a Secure Connection:

When dealing with PCB board terminal blocks, it is crucial to establish a secure connection. The 2-pin screw terminal block connector allows for a tight and precise connection, reducing the risk of loose or weak connections. This ensures the efficient flow of signals between components and minimizes potential signal interference.

 

3 pole terminal block

Enhanced Safety with Barrier Terminal Blocks:

For applications that require higher safety measures, the PCB barrier terminal block comes into play. It offers additional insulation and protection, reducing the risk of short circuits and accidental contact. With its design, the barrier terminal block prevents damage to the conductors and minimizes the chances of electrical hazards.

 

Effective Wiring with 3-Pole Terminal Blocks:

In scenarios where multiple connections are necessary, the 3-pole terminal block becomes essential. It provides a convenient solution for connecting three conductors together, ensuring a neat and organized wiring arrangement. The 3-pole terminal block simplifies the installation process and enables efficient power distribution and control within the PCB board.

 

The Advantages of HONG YI-HOMNECKS+PCB Terminal Blocks:

Recognized as a leading manufacturer and supplier of high-quality terminal blocks, HONG YI-HOMNECKS ensures exceptional performance and reliability. Their PCB terminal blocks offer superior conductivity, durability, and optimal signal transfer. With a wide range of options, including 2-pin and 3-pole terminal blocks, they cater to various application requirements.

 

HONG YI-HOMNECKS' Commitment to Exceptional Service:

In addition to their top-notch products, HONG YI-HOMNECKS prioritizes customer satisfaction and provides excellent service. Their team of experts is dedicated to assisting customers in selecting the right terminal blocks for their specific needs. With HONG YI-HOMNECKS, you can expect timely support, technical guidance, and reliable solutions that ensure successful project outcomes.

 

Properly wiring PCB board terminal blocks is essential for achieving efficient signal transmission and maintaining a secure electrical connection. By choosing the right terminal connector, implementing secure connections, and utilizing appropriate terminal blocks like 2-pin screw terminal connectors, barrier terminal blocks, and 3-pole terminal blocks, you can ensure optimal performance and safety. For high-quality terminal blocks and exceptional service, trust HONG YI-HOMNECKS+PCB Terminal Blocks to meet your requirements with precision and reliability.

Basics of valves

In the fluid piping system, the valve is a control element, its main role is to isolate the equipment and piping system, regulate flow, prevent backflow, regulate and discharge pressure.

Valves can be used to control the flow of various types of fluids such as air, water, steam, various corrosive media, slurries, oils, liquid metals and radioactive media. Since the selection of the most suitable valve for the piping system seems to be very important, it becomes vital to understand the characteristics of the valve and the steps and basis for selecting the valve.


The classification of the valve

Valves can be divided into two main categories:

1. Automatic valves

Relying on the medium (liquid, gas) the ability to act on its own valves.

Such as check valves, safety valves, control valves, traps, pressure reducing valves.

2. Drive the valve

With manual, electric, hydraulic, pneumatic to manipulate the action of the valve.

Such as gate valves, globe valves, throttle valves, butterfly valves, ball valves, plug valves and so on.

According to the structural characteristics, according to the direction of the closing member relative to the valve seat movement can be divided into:

(1) Gate shape: the closing member moves along the center of the valve seat;

(2) Gate shape: the closing member moves along the center of the vertical valve seat;

(3) Plunger and ball: the closing member is a plunger or ball, rotating around its own centerline;

(4) Rotary opening shape: the closing member rotates around the axis outside the valve seat;

(5) Disc shape: the disc of the closing member, rotating around the axis inside the valve seat;

(6) Slide valve shape: the closing member slides in the direction perpendicular to the passage.

According to the use, according to the different uses of the valve can be divided into:
(1) Open and close with: used to connect or cut off the pipeline medium, such as globe valves, gate valves, ball valves, butterfly valves and so on.
(2) Check: used to prevent the medium backflow, such as check valves.
(3) Regulation: used to adjust the pressure and flow of the medium, such as regulating valves, pressure reducing valves.
(4) Distribution: used to change the direction of media flow, distribution of media, such as three-way plug, distribution valves, slide valves.
(5) Safety valve: in the medium pressure exceeds the specified value, used to discharge excess media, to ensure the safety of piping systems and equipment, such as safety valves, accident valves.
(6) Other special purposes: such as traps, air release valves, sewage valves, etc..
According to the drive mode, according to the different drive mode can be divided into:
(1) Manual: with the help of handwheels, handles, levers or sprockets, etc., there are manpower drive, transmission of large torque is equipped with worm gears, gears and other deceleration devices.
(2) Electric: with the help of motor or other electrical devices to drive.
(3) Hydraulic: with the help of (water, oil) to drive.
(4) Pneumatic: driven by compressed air.
According to the pressure, according to the nominal pressure of the valve can be divided into:
(1) Vacuum valves: absolute pressure <0.1Mpa that is, 760mm Hg high valves, usually mm Hg or mm water column pressure.
(2) Low-pressure valves: nominal pressure PN ≤ 1.6Mpa valves (including PN ≤ 1.6MPa steel valves)
(3) Medium pressure valve: nominal pressure PN2.5-6.4MPa valve.
(4) High-pressure valve: nominal pressure PN10.0-80.0MPa valve.
(5) Ultra-high pressure valve: nominal pressure PN ≥ 100.0MPa valve.
According to the temperature of the medium, according to the temperature of the medium when the valve works can be divided into:
(1) Ordinary valves: applicable to the medium temperature -40 ℃ ~ 425 ℃ valve.
(2) High-temperature valves: for media temperature 425 ℃ ~ 600 ℃ valve.
(3) Heat-resistant valves: for media temperature of 600 ℃ above the valve.
(4) Low-temperature valves: for media temperature -150 ℃ ~ -40 ℃ valve.
(5) Ultra-low temperature valves: for media temperature -150 ℃ below the valve.
According to the nominal diameter, according to the nominal diameter of the valve can be divided into:
(1) Small diameter valve: nominal diameter DN <40mm valve.
(2) Medium caliber valves: nominal diameter DN50 ~ 300mm valve.
(3) Large caliber valves: nominal diameter DN350 ~ 1200mm valve.
(4) Large caliber valves: nominal diameter DN ≥ 1400mm valve.
According to the way of connection with the pipeline, according to the valve and pipeline connection can be divided into:
(1) Flange connection valve: valve body with a flange, and the pipeline using flange connection valve.
(2) Threaded connection valve: valve body with internal or external threads, and the pipeline using threaded connection valve.
(3) Welded connection valve: valve body with weld, and the pipeline using welded connection valve.
(4) Hoop connection valve: the valve body with a clamp port, and the pipeline using the hoop connection valve.

(5) Ferrule connection valve: the use of ferrule and pipe connection valve.


The characteristics of the valve

Valve characteristics generally have two kinds of characteristics, the use of characteristics and structural characteristics.

1. The use of characteristics

It determines the main use of the valve performance and scope of use, belonging to the use of the valve characteristics:

  • Valve category (closed-loop valves, regulating valves, safety valves, etc.);
  • Product type (gate valve, globe valve, butterfly valve, ball valve, etc.);
  • Materials of the main parts of the valve (valve body, valve cover, valve stem, valve flap, sealing surface);
  • Valve transmission mode, etc.

2. Structural characteristics

It determines the valve installation, repair, maintenance and other methods of some structural characteristics, belonging to the structural characteristics:

  • Valve structure length and overall height, and pipeline connection form (flange connection, threaded connection, clamped hoop connection, external threaded connection, welded end connection, etc.);
  • The form of sealing surface (inlay ring, threaded ring, surfacing, spray welding, valve body body);
  • The form of valve stem structure (rotating stem, lifting stem) and so on.


The selection of the steps and basis of the valve

1. Selection steps

(1) Clearly the use of the valve in the equipment or device to determine the working conditions of the valve: applicable media, operating pressure, operating temperature, etc..

(2) Determine the nominal diameter of the pipeline connected to the valve and connection: flange, threaded, welded, etc..

(3) Determine the way to operate the valve: manual, electric, electromagnetic, pneumatic or hydraulic, electrical linkage or electro-hydraulic linkage.

(4) According to the pipeline medium, working pressure, working temperature to determine the selected valve shell and inner parts of the material: gray cast iron, malleable cast iron, ductile iron, carbon steel, alloy steel, stainless acid-resistant steel, copper alloy, etc..

(5) Select the type of valve: closed-circuit valves, regulating valves, safety valves and so on.

(6) Determine the type of valve: gate valves, globe valves, ball valves, butterfly valves, throttle valves, safety valves, pressure reducing valves, steam traps, etc.

(7) Determine the parameters of the valve: for automatic valves, according to the different needs of the first to determine the allowable flow resistance, discharge capacity, back pressure, etc., and then determine the nominal diameter of the pipeline and the diameter of the valve seat hole.

(8) Determine the geometric parameters of the selected valve: structural length, flange connection form and size, open and close the valve after the height direction of the size, the size and number of bolt holes to connect, the entire valve dimensions, etc..

(9) The use of existing information: valve catalogs, valve product samples, etc. to select the appropriate valve products.

2. The basis for selecting the valve

In understanding the steps to master the selection of valves at the same time, should further understand the basis for selecting the valve.

(1) The purpose of the selected valve, the use of working conditions and manipulation control.

(2) The nature of the working medium: working pressure, working temperature, corrosive properties, whether it contains solid particles, whether the medium is toxic, whether it is flammable, explosive media, the viscosity of the medium and so on.

(3) The requirements of the valve fluid characteristics: flow resistance, discharge capacity, flow characteristics, sealing grade and so on.

(4) Installation size and size requirements: nominal diameter, connection with the pipeline and connection size, dimensions or weight limitations.

(5) Of the valve product reliability, service life and explosion-proof performance of electric devices and other additional requirements.

Attention should be paid when selecting parameters:

If the valve is to be used for control purposes, the following additional parameters must be determined: method of operation, the maximum and minimum flow requirements, the pressure drop in normal flow, the pressure drop when closed, the maximum and minimum inlet pressure of the valve.

According to the above selection of valves based on the basis and steps, reasonable and correct selection of valves must also be a detailed understanding of the internal structure of various types of valves, in order to be able to prioritize the selection of valves to make the right choice.

The final control of the pipeline is the valve. Valve opening and closing parts of the control of the medium in the pipeline beam way, the shape of the valve flow path so that the valve has a certain flow characteristics, in the selection of piping system is most suitable for the installation of the valve must take this into account.

Selection of valves should follow the principles:
(1) Shut-off and open medium with the valve
Flow path for the straight-through valve, its flow resistance is small, usually selected as a cut-off and open medium with the valve. Downward closing type valve (globe valve, plunger valve) due to its flow path zigzag, flow resistance is higher than other valves, so less selection. Allow a higher flow resistance of the occasion, you can choose to close the valve.
(2) Valves for flow control
Usually choose the valve that is easy to adjust the flow rate as the control flow rate. Downward closing type valves (such as globe valves) is suitable for this purpose, because its seat size is proportional to the stroke between the closing member. Rotary valves (plug valves, butterfly valves, ball valves) and flexure body type valves (clamp valves, diaphragm valves) can also be used for throttling control, but are usually only applicable within a limited range of valve sizes. Gate valve is a disc-shaped gate on the circular valve seat mouth to do cross-cutting movement, it is only close to the closing position, can better control the flow, so usually not used for flow control.
(3) Reversing and diverting valves
According to the need for commutation and diversion, this valve can have three or more channels. Plug valves and ball valves are more suitable for this purpose, therefore, most of the valves used for commutation of flow diversion are selected one of these valves. But in some cases, other types of valves, as long as the two or more valves properly connected to each other, can also be used for reversing the flow.
(4) Valves for media with suspended particles

When the medium with suspended particles, the most suitable for the use of its closure along the sealing surface of the sliding with the wiping effect of the valve. If the closing member of the seat of the back and forth movement is vertical, then it may be entrapped particles, so this valve unless the sealing surface material can allow embedded particles, otherwise only suitable for basic clean media. Ball valves and plug valves in the opening and closing process of the sealing surface are wiping effect, so it is suitable for use in the medium with suspended particles.


The valve selection instructions

1. Gate valve selection

In general, the gate valve should be preferred. In addition to the gate valve for steam, oil and other media, but also for the media containing granular solids and viscosity, and for the venting and low vacuum system valves. For media with solid particles, the gate valve body should be with one or two blow holes. For low-temperature media, should be used for low-temperature special gate valve.

2. Globe valve selection instructions

Globe valve is suitable for the fluid resistance requirements are not strict pipeline, that is, the pressure loss is not a big consideration, as well as high temperature, high pressure media pipeline or device, suitable for DN <200mm steam and other media pipeline; small valves can be used to select the globe valve, such as needle valves, instrumentation valves, sampling valves, manometer valves, etc.; Globe valve flow regulation or pressure adjustment, but the regulation of the accuracy of the requirements of the high, and the diameter of the pipeline and Comparison of hours, it is appropriate to use the globe valve or throttle valve; for highly toxic media, it is appropriate to use the bellows sealed globe valve; but the globe valve should not be used for viscosity of the medium and contain particles easy to precipitate the medium, but also should not be used as a bleeder valve and the valve of the low-vacuum system.

3. Ball valve selection instructions

Ball valves are suitable for low temperature, high pressure, viscosity of the medium. Most ball valves can be used in the medium with suspended solid particles, according to the material requirements of the seal can also be used for powdery and granular media; full-channel ball valves are not suitable for flow regulation, but suitable for the requirements of rapid opening and closing occasions, to facilitate the realization of the accident emergency cut off; usually in the sealing performance is strict, wear and tear, indentation of the channel, open and close quickly, high-pressure cut-off (differential pressure is large), low-noise, cavitation phenomenon, the operating torque is small, the fluid resistance. Torque is small, small fluid resistance in the pipeline, the recommended use of ball valves; ball valves are suitable for lightweight structure, low-pressure cut-off, corrosive media; ball valves or low-temperature, deep-cold media, the most ideal valve, low-temperature media piping systems and devices, it is appropriate to choose to add the bonnet of the low-temperature ball valves; selection of floating ball ball valves when the seat material should undertake the ball and the working medium of the load, the large-diameter ball valves need to be larger when operating Force, DN ≥ 200mm ball valve should be selected worm gear drive form; fixed ball valve for larger caliber and higher pressure occasions; in addition, for the process of highly toxic materials, combustible media pipeline ball valve, should have a fire prevention, anti-static structure.

4. Throttle valve selection instructions

Throttle valve is suitable for medium temperature is low, high pressure occasions, suitable for the need to regulate the flow and pressure of the parts, does not apply to viscosity and contain solid particles of the medium, should not be used as a partition valve.

5. Plug valve selection instructions

Plug valves are suitable for occasions requiring rapid opening and closing, generally not applicable to steam and higher temperature media, for lower temperature, viscosity of the media, but also applicable to the media with suspended particles.

6. Butterfly valve selection instructions

Butterfly valve is suitable for larger caliber (such as DN>600mm) and short structure length requirements, as well as the need for flow regulation and opening and closing requirements for rapid occasions, generally used for temperature ≤ 80 ℃, pressure ≤ 1.0MPa water, oil and compressed air and other media; due to the butterfly valve relative to the gate valve, the ball valve pressure loss is relatively large, the butterfly valve is suitable for pressure loss requirements are not stringent piping system.

7. Check valve selection instructions

Check valve is generally applicable to clean media, should not be used for solid particles and viscosity of the medium.

  • When DN ≤ 40mm, it is appropriate to use lift check valve (only allowed to be installed in the horizontal pipeline);
  • When DN = 50 ~ 400mm, it is appropriate to use the rotary lift check valve (in the horizontal and vertical pipeline can be installed, such as installation in the vertical pipeline, the media flow direction should be from the bottom up);
  • When DN ≥ 450mm, it is appropriate to use buffer type check valve;
  • When DN = 100 ~ 400mm can also choose to use the clamp type check valve;

Swing check valve can be made into a very high working pressure, PN can reach 42MPa, according to the shell and sealing material can be applied to any working medium and any working temperature range. The medium is water, steam, gas, corrosive media, oil, pharmaceuticals and so on. Medium working temperature range between -196 ~ 800 ℃.


8. Diaphragm valve selection instructions

Diaphragm valve is suitable for working temperature less than 200 ℃, pressure less than 1.0MPa oil, water, acidic media and media containing suspended solids, not for organic solvents and strong oxidizing agents media; abrasive particulate media should be selected weir diaphragm valve, weir diaphragm valve to refer to the flow characteristics of the table; viscous fluids, cement slurry, and precipitation media should be selected through the type of diaphragm valve; in addition to the specific requirements, diaphragm valve Should not be used for vacuum piping and vacuum equipment.

Valve applications, frequency of operation and service varies greatly, to control or eliminate even the slightest leakage, the most important, the most critical equipment is still the valve. Learning the proper selection of valves is critical.



Common faults and maintenance methods of corrosion-resistant self-priming pumps

What are the common faults and maintenance methods of corrosion-resistant self-priming pumps? As described below:


The pump head part of corrosion-resistant self-priming pump:


1. Most cases where the casing is electrified have water seal damage, causing water to seep into the motor through the shaft and deteriorate the insulation performance. This can be repaired by replacing the water seal or drying the motor.


2. Although the motor is running normally, the water output is low or not at all. In this case, the sealing of the pump must be checked first. When checking, first unplug the power plug, block the suction port with your hand, fill the pump with water, hold the mouth with your mouth and blow air inside with force, observe whether the pump head leaks water, that is, if the seal is damaged. Common faulty parts include the suction port gasket, outlet gasket, and impeller cover gasket, which should be replaced during maintenance.


Corrosion resistant self-priming pump motor part:

1. There is no response even after connecting the power supply. This situation is mostly caused by short circuits in the power plug, power outlet, and motor coil.


2. Difficult to start or unable to start, accompanied by a buzzing sound. During inspection, a small bamboo blade can be used to quickly move the wind shear in the driving direction. If the motor runs quickly, it indicates that the starting capacitor or starting coil is damaged. Please replace the capacitor with the same capacity or repair the starting winding. If it is a problem with the motor, it is mostly caused by mechanical failures of the motor and pump head, such as bearing damage, impeller adhesion, etc.


3. The motor can work, but the speed is slow and the casing is overheated, with a burnt smell. Most of them are caused by short circuits in the motor coils, and the motor needs to be disassembled. Depending on the damage, measures such as welding, jumper wires, isolation, and rewinding should be taken for repair.


4. There is loud noise and vibration during homework. In most cases, due to bearing damage or improper fitting between the bearing and the housing, the motor should be disassembled and inspected. If the bearing is damaged, it should be replaced.