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.

1、 Installation

1）. Preparation before installation:

Check valve parameters: Carefully verify the diameter, pressure range, spring pressure, and other parameters of the steam pressure reducing valve to ensure they match the selected data.

Cleaning the pipeline system: Before installation, the pipeline system needs to be thoroughly cleaned to remove impurities such as welding slag, debris, and oxide scale. A 100 mesh steam filter can be installed in front of the pressure reducing valve. The filter screen is made of corrosion-resistant double-layer stainless steel filter, and the filter head is installed on the side to avoid water accumulation.

Prepare installation tools and materials: Ensure that the necessary tools for installation are complete, such as wrenches, screwdrivers, etc., and prepare suitable connecting fittings, gaskets, and other materials.

2. Installation position and direction
Horizontal installation is preferred: Steam pressure reducing valves are generally recommended to be installed on horizontal pipelines, with the valve cover facing upwards for easy operation and maintenance. They should be installed in the direction of the arrow on the valve body, so that they are consistent with the direction of fluid flow and cannot be installed in reverse.

Attention to straight pipe section requirements: There should be a certain straight pipe section before and after the installation of the pressure reducing valve. The length of the straight pipe in front of the valve is about 600 millimeters, and the length of the straight pipe behind the valve is about 1000 millimeters.

3. Installation of supporting facilities

Install bypass valve: Install an adjustable steam shut-off valve on the bypass pipeline of the pressure reducing valve. The diameter of the bypass valve should be the same as that of the pressure reducing valve, and it should be installed on the top of the pressure reducing valve as much as possible to avoid corrosion caused by water accumulation. Installation pressure

Gauge and safety valve: Install a pressure gauge before and after the pressure reducing valve for pressure setting and monitoring. At the same time, a steam safety valve should be installed downstream of the pressure reducing valve. The set pressure of the safety valve should be higher than the upper deviation of the pressure reducing valve, but lower than the maximum pressure at which the equipment or control valve closes.
Installation of steam water separator and drain valve: Install a steam water separator or drain valve at the inlet of the pressure reducing valve to reduce and eliminate water hammer and erosion, or install a drain valve at the outlet of the pressure reducing valve.

4、 Maintenance
1). Daily maintenance to maintain cleanliness: Regularly clean the dust, oil stains, and other dirt on the surface of the pressure reducing valve to prevent impurities from entering the valve body and affecting its performance. Check the connection parts: Regularly check the connection parts between the pressure reducing valve and the pipeline for looseness, leakage, etc. If there are any problems, tighten or replace the seals in a timely manner. Observing the operating status: During operation, closely observe the working status of the pressure reducing valve, including whether the pressure regulation is stable, whether the valve action is flexible, etc. If there are any abnormalities, they should be dealt with in a timely manner.

2). Regular maintenance and inspection of filters: Regularly clean or replace the filter screen before the pressure reducing valve to prevent impurities from blocking the filter screen and affecting the filtration effect. Check the seals and springs: Every certain time, check whether the seals of the pressure reducing valve are worn or aged, and whether the springs are deformed or broken. If there are any problems, replace them in a timely manner. Calibration of pressure gauge: Regularly calibrate the pressure gauge before and after the pressure reducing valve to ensure accurate pressure display, in order to facilitate correct adjustment and monitoring of pressure.

3). Long term shutdown maintenance emptying pipeline: When the steam pressure reducing valve is not in use for a long time, the front and rear shut-off valves should be closed to empty the steam and condensate in the pipeline, to prevent water accumulation from corroding the valve components. Apply protective oil: Apply protective oil to the exposed machined surface of the pressure reducing valve to prevent rust and store it properly.

1、 Working principle

The working principle of a pressure reducing valve is mainly achieved by adjusting the opening of the valve and utilizing the pressure loss generated by the fluid passing through the throttle to achieve the pressure reducing function. It generally includes an adjustable valve core structure. When fluid flows in from the inlet, passes through the throttling area between the valve core and the valve seat, the pressure decreases, and then flows out from the outlet. Under normal circumstances, the inlet pressure acts on one side of the valve core, and the outlet pressure acts on the other side of the valve core through the control channel. The pressure difference between the two is balanced with the spring force, thereby determining the position of the valve core and the opening of the valve.

2、 Analysis of the state when the import is blocked

1) Spring type pressure reducing valve

Valve core position:

When the inlet is blocked, no fluid enters the pressure reducing valve, and the valve core will be in a closed state under the action of spring force. Because there is no import pressure to counteract the spring force, the spring will push the valve core towards the valve seat, causing the valve to close tightly. For example, in a simple water spring pressure reducing valve, after the inlet pressure disappears, the spring will cause the valve core to tightly adhere to the valve seat, preventing any reverse flow or accidental opening.

Changes in export pressure:

Due to the lack of new fluid replenishment, the pressure on the outlet side will gradually decrease with the use or leakage of downstream equipment. If the downstream is a closed system and there is no leakage, the outlet pressure will remain basically unchanged, but once there is any trace leakage or usage, the pressure will decrease until it reaches equilibrium with the external environmental pressure or the system is completely depressurized.

3. The difference between constant pressure reducing valve and proportional pressure reducing valve

Fixed pressure reducing valve:
Whether it is a spring-loaded constant pressure reducing valve or a pilot operated constant pressure reducing valve, the main state when the inlet is blocked is that the valve core is closed and the outlet pressure drops. The purpose of a constant pressure reducing valve is to lower the inlet pressure to a fixed output value. When there is no pressure input from the inlet, it cannot achieve the pressure reducing function and only remains closed to prevent backflow and other situations.

Proportional pressure reducing valve:

The output pressure and inlet pressure of the proportional pressure reducing valve are adjusted according to a certain proportional relationship. When the inlet is blocked, like a constant pressure reducing valve, the valve core closes and the output pressure decreases with downstream conditions. However, its internal structure may be slightly more complex due to the design characteristics of proportional adjustment, and the adjustment process may be slightly more complicated when the inlet pressure is restored, requiring the re establishment of control parameters such as valve core position corresponding to proportional relationships.