The control of internal leakages and external leakages The internal and external leakages control of the valve is an important parameter that reflects the quality of the valve. The manufacturer has adopted various measures to minimize the internal leakage and external leakage of the valve. The internal and external leakages of oil and hydrogen will not only pollute the environment, but also cause a fire or an explosion. The internal leakage of the valve mainly occurs at the wedge,...
The Leakage Control of Valves Used for High-pressure Hydrogenation Units Read
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A valve is one of the important pressure piping components in petrochemical plant, among which process valves are used in a relatively large amount. They are mainly used for opening, closing, and throttling. A process valve is a relatively complex and high-tech mechanical product assembled from multiple parts in pipeline components. The particularity of the petrochemical industry determines that its special requirements for valves will continue to increase, and at...
The Development Trend of Valves in the Petrochemical Industry Read
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1. Technical requirements 1.1 Requirements on valves for large-scale devices As the equipment becomes large-scale, the size of process pipelines is getting larger and larger. The number of valves is also increasing. Taking a 3.8 million t/a continuous reforming unit as an example, the number and specifications of process valves are shown in Table 1. Table 1 Statistics of 3.8 million t/a continuous reforming process valves Valve types Specifications/DN...
Research on the Application Status of Valves in Petrochemical Devices Read
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Static sealing usually refers to the sealing between two static surfaces, and it mainly uses gaskets. (1) Materials of gaskets (a) Non-metal gaskets: They are gaskets made from materials such as paper, linen, cowhide, asbestos products, plastic, rubber, etc. Paper, linen and cowhide have capillary pores and are easy to penetrate, so they must be impregnated with oil, wax or other impermeable materials when used. Generally, they are rarely used for valves. Asbestos products...
The Static Sealing of the Valve Read
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The sealing of the valve cannot be ignored, because most of the valve's leakages occur due to sealing. The related information of dynamic sealing of valves is discussed in this article. 1. The dynamic sealing of the valve The dynamic sealing of the valve mainly refers to the sealing of the valve stem. Preventing the medium in the valve from leaking due to the movement of the valve stem is the key to solving the problem of the valve's dynamic sealing....
The dynamic sealing of the valve Read
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2.3 Finding and confirming the failure (1) The inspection of the valve body The pipeline was opened and it was found that the valve plate was in the middle state. The valve plate was knocked lightly with a copper rod and nothing happened, indicating that the drive part of the valve plate has jammed and caused the valve body to fail to move (Figure 4). Figure 4 The jamming of the valve plate (2) The inspection of the hydraulic station The globe valve, one-way...
The Analysis and Maintenance of Failure Causes of Hydraulic Check Valves (Part Two) Read
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Abstract The reliability of the hydraulic check valve on the pipeline of the circulating water system directly affects the safe operation of the circulating water pump. The hydraulic pressure of the hydraulic check valve at the outlet of the circulating water pump could not be maintained after inspection, and the oil pump was frequently started and stopped. The check valve could not be opened or closed. After the valve was opened, the motor and oil pump tank were overheated. In view...
The Analysis and Maintenance of Failure Causes of Hydraulic Check Valves (Part One) Read
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An eccentric semi-ball valve is a relatively new type of ball valve, which has some unique advantages related to the structure, including opening and closing without friction, sealing not being worn easily, and small opening and closing torque. This can reduce the size of the actuator and a multi-turn electric actuator can be equipped, which can achieve the purpose of the adjustment and close cutting off of the medium. An eccentric semi-ball valve is widely...
Eccentric Semi-ball Valves and V-shaped Ball Valves Read
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In order to study the performance, rules of size changes at low temperatures, changes of microstructure, and cracking of surfacing layers of the valve body's material AISI 304 and the sealing surface surfacing Ni40 and Ni60 hard alloys at low temperatures, the following tests were carried out: The hardness gradient test from the base metal to the surfacing layer before and after the cryogenic treatment AISI 304 impact and tensile tests at room...
Low-temperature Physical Property Analysis of Key Materials of Valves Read
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