Pressure testing method for ball valves
The strength test of the pneumatic ball valve should be carried out in the semi-open state of the ball.
(1) Floating ball valve tightness test: the valve is in a half-open state, one end is introduced into the test medium, and the other end is closed; Turn the ball several times, open the closed end when the valve is closed, and check the sealing performance of the packing and gasket at the same time, and there shall be no leakage. Then introduce the test medium from the other end and repeat the above test.
(2) Tightness test of fixed ball valve: before the test, the ball is rotated several times without load, and the fixed ball valve is in a closed state, and the test medium is drawn to the specified value from one end; Use a pressure gauge to check the sealing performance of the inlet end, and use the pressure gauge with an accuracy of 0.5-1 grade, and the range is 1.5 times of the test pressure. Within the specified question, there is no blood pressure reduction phenomenon is qualified; Then introduce the test medium from the other end and repeat the above test. Then, the valve is in a half-open state, both ends are closed, the inner cavity is filled with medium, and the packing and gasket are checked under the test pressure without leakage.
(3) Three-way ball valves should be tested for tightness in various positions.
Pressure test method of pressure reducing valve
(1) The strength test of the pressure reducing valve is generally assembled after the single piece test, and the test can also be carried out after assembly. The duration of the strength test is DN<50mm, DN65-150mm, more than 2min, DN>150mm, and more than 3min. After the bellows is welded to the component, the strength test is carried out with air at 1.5 times the highest pressure after applying the pressure reducing valve.
(2) The tightness test shall be carried out according to the actual working medium. When tested with air or water, the test is carried out at 1.1 times of the nominal pressure, and when tested with steam, it is carried out at the highest allowable working pressure at the working temperature. The difference between the inlet pressure and the outlet pressure is not less than 0.2MPa. The test method is as follows: after the inlet pressure is adjusted, gradually adjust the adjusting screw of the valve, so that the outlet pressure can change sensitively and continuously within the range of large and small values, and there shall be no stagnation and jamming. For the steam pressure reducing valve, when the inlet pressure is adjusted away, the valve is closed and the outlet pressure is high and low, within 2min, the appreciation of the outlet pressure should meet the provisions in Table 4.176-22, at the same time, the volume of the pipeline behind the valve is qualified in Table 4.18;
Pressure test method of safety valve
(1) The strength test of the safety valve is the same as that of other valves, which is tested with water. When the lower part of the test valve body is tested, the pressure is introduced from the inlet I=I end, and the sealing surface is closed; When testing the upper part of the body and bonnet, the pressure is introduced from the outlet end and the other ends are closed. No leakage of the valve body and bonnet within the specified time is qualified.
(2) For tightness test and constant pressure test, the general medium used is: saturated steam is used as the test medium for steam safety valve; Valves for ammonia or other gases use air as the test medium; Valves for water and other non-corrosive liquids use water as the test medium. For safety valves in some important positions, nitrogen is often used as the test medium.
The sealing test is carried out with the nominal pressure value as the test pressure, and the number of times is not less than two, and no leakage within the specified time is qualified. There are two ways to detect leakage: one is to seal the connections of the safety valve, seal the tissue paper with butter on the flange, and the tissue paper is bulging for leakage, and not bulging for qualification; The second is to use butter to seal the thin plastic plate or other plates in the lower part of the outlet flange, fill the water to seal the valve disc, and check that the water is not bubbling to be qualified. The number of constant pressure and return pressure tests of the safety valve shall not be less than 3 times, and it shall be qualified if it meets the regulations. For the performance tests of safety valves, please refer to GB/T 12242 "Safety Valve Performance Test Methods".
|
More on that
|
DVC6200 &DVC2000 Smart Positioner Online Performance Diagnostics - Fisher Fisher Valves
Fisher's Fisher Valve DVC6200 &DVC2000 Smart Positioners allow users to configure, calibrate, and adjust their instruments, bringing a new level of reliability to the range of products through years of experience in the control industry. This helps to identify problems accurately without interrupting the process ...
|
|
Fisher Fisher - Valve Positioner Steps to get the correct valve diagnostic analysis data
What should I pay attention to when the automatic initialization of the valve positioner is unsuccessful?
DVC6200 smart valve positioners need to be initialized before they are put into use, and due to incorrect installation and use, they often run into trouble during the initialization process. place
There are several aspects that need to be noted:
1 ...
|
|
Fisher Fisher - Analysis of the level of valves in China's nuclear power
At present, 19 domestic enterprises have obtained the civil nuclear pressure equipment planning and production qualification license issued by the National Nuclear Safety Administration, which can plan and produce nuclear-grade valves. The types of planning and production valves include gate valves, globe valves, check valves, ball valves, butterfly valves, tension spring safety valves, and regulators.
|
|
Fisher Fisher - Why do steam pipes often have to be bent a section?
We often see such a scene on the steam pipeline, the pipe section that can be "straight" suddenly bent a section, I believe that many people who have seen it will have such doubts like me, this is not "painting snakes", in fact, the design of the pipeline operation has its own original...
|
|
Fisher Fisher - Classification of specific areas of use and types of transmitters
Sensor - A device or device that can sense a measured pattern and convert it into a usable output signal according to the rule. It is generally composed of sensitive elements and conversion elements. A simple sensor is composed of a component (which also serves as a conversion element), which directly outputs electricity when it senses the measurement, such as thermoelectric ...
|
|
Fisher Fisher - The Fisher controller has three general functions
The Fisher Fisher controller is primarily a system that uses digital codes representing processing parameters, processing sequences, and processing methods as control commands. Its processing efficiency and machining accuracy are both
It is used in many places where small batches are produced, and it is also very popular. Then the editor is a big ...
|
|
Fisher Flow Amplifier ASCO 614 Series Solutions
The Fisher/fisher ASCO Series 614 SentronicPlus is a digitally operated, three-way proportional regulator. Adjustable pressure, flow, force, speed, and linear or angular position. Air and inert gas media can be controlled. According to the ATEX Directive 2014/34/EU, its structure ...
|
|
Fisher Fisher - Vacuum solenoid valves in the food processing industry
With the rapid development of the food processing industry, the supporting products have been more and more widely used, among which the main equipment of rock sugar processing swing crystallization kettle as an example, it is composed of two parts: the main body of the kettle and the transmission, which contains the sugar liquid nozzle and the vacuum nozzle, so it is set up here.
|
|
Fisher Fisher - 6 Packing Material Selection Methods for Valve Stem Seals
When choosing a valve stem packing, it should be determined according to the specific conditions. The method we generally choose is: between pressure and temperature, only one *** value can be satisfied; When choosing a high-temperature valve packing, the temperature should be considered first; For corrosive media with low temperature and pressure, the ...
|
|
Understanding flash in control valves and how to minimize metal corrosion damage?
The Fisher FISHER control valve reduces maintenance costs, minimizing the effects of metal corrosion damage due to water spray.
Learn about flash evaporation in control valves
Flickering occurs when a liquid flows through a control valve and evaporates and retains the vapor. Scintillation with choke flow and cavitation have ...
|
|
FISHER DVC2000/DVC6200 Smart Valve Valve Positioner Calibration
FISHER Valve Positioner From mechanical to intelligent, FISHER Intelligent Valve Positioner can effectively reduce the labor intensity of maintenance personnel in the first line. Intelligent communication mode: The obvious feature of intelligent valve positioner is intelligent communication. For our process industry ...
|
|
Fisher Fisher - Seven common problem solutions for pneumatic butterfly valves
Seven common problem solutions for pneumatic butterfly valves:
1. The butterfly valve is installed in the pipeline, and the best position is vertical, but it cannot be reversed.
2. It is recommended to use the special flange of the butterfly valve, that is, the HGJ54-91 socket welded steel flange.
3. Butterfly valve stem installation ...
|
|
Debugging steps for the Fisher Locator (DVC6200).
The Fisher Positioner DVC6200 is Emerson's valve-mounted, digital valve controller that intelligentizes the entire control valve assembly. Take control of your process with important, real-time information that can be accessed from anywhere in the loop. Also able to get a problem before it becomes ...
|
|
Fisher positioners in the pulp and paper industry
FISHER Locator is a division of Emerson Electric Company, a Fortune 500 United States. In 1992, Emerson acquired Fisher and merged with Rosemount, another world leader in process instrumentation, to form Fisher-Rosemount to better ...
|
|
Fisher Fisher-Cavitation Valve Trim helps improve plant availability and safety.
Emerson's Fisher ™ Kaft Hex Valve Strict working valve trimming reduces or eliminates cavitation to improve rotary valve performance and extend service life. The Fisher Vee-Ball Rotary™ Control Valve is now available with the Cavertro ™ Hex Valve Anti-Cavitation Trim to reduce or eliminate the effects of cavitation.
|
|
Fisher Fisher - Gas Pressure Reducing Valve Operating Principle and Selection Criteria
The gas pressure reducing valve is to control the opening of the opening and closing parts in the valve body to adjust the flow of the medium, reduce the pressure of the medium, and at the same time adjust the opening of the opening and closing parts with the help of the pressure behind the valve, so that the pressure behind the valve is kept within a certain range, and the cooling water is sprayed in the valve body or behind the valve to reduce the pressure of the medium.
|
|
Fisher Fisher—Why cryogenic valves use long neck bonnets
Valves suitable for medium temperature -40 °C ——- 196 °C are called cryogenic valves, and such valves generally use long neck bonnets.
Adopt a long neck valve
|
|
Fisher – Fisher – Valve positioner hardware system design
The system hardware design of the valve positioner needs to reduce the interference between the analog ground and the digital ground, and at the same time make full use of the internal space of the positioner housing to divide the hardware system into two parts: the main control board and the interface board.
Among them, the main control board of the valve positioner includes a single-chip microcomputer Z small system and a human-computer interaction model.
|
|
Fisher Fisher - Five Essentials for Valve Installation
Emerson's Fisher Fisher valve installation five key points:
First, direction.
Many valves are directional.
Such as globe valves, throttle valves, pressure reducing valves, check valves, etc. , if installed in reverse, it will ...
|
|
What are the advantages and disadvantages of Fisher Fisher - Globe Valves?
Today we will explain what are the advantages and disadvantages of the globe valve, we all know that the globe valve is a common on-off valve that cuts off the pipeline medium, let's take a look.
Globe valves have the following advantages:
1. The structure is simple, and the manufacturing and maintenance are relatively convenient.
2. Work itinerary ...
|
|
Contact
working hours
