Industry terminology of the hottest valve

2022-08-14
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The industry term of valve

strength performance the strength performance of a valve refers to the ability of the valve to withstand medium pressure. Valves are mechanical products that bear internal pressure, so they must have sufficient strength and stiffness to ensure long-term use without cracking or deformation

sealing performance the sealing performance of a valve refers to the ability of each sealing part of the valve to prevent medium leakage, which is the most important technical performance index of the valve. There are three sealing parts of the valve: the contact between the two sealing surfaces of the hoist and the valve seat; Packing, valve stem and stuffing box; The connection between valve body and bonnet. The leakage in the former part is called internal leakage, which is usually said that if it is not closed tightly, it will affect the ability of the valve to cut off the medium. For block valves, internal leakage is not allowed. The leakage at the last two places is called external leakage, that is, the medium leaks from inside the valve to outside the valve. Leakage will cause material loss, pollute the environment, and even cause accidents in serious cases. For flammable, explosive, toxic or radioactive media, leakage is not allowed, so the valve must have reliable sealing performance

flowing medium the medium will produce pressure loss after flowing through the valve (i.e. the pressure difference between the front and back of the valve), that is, the valve has a certain resistance to the flow of the medium, and the medium will consume a certain amount of energy to overcome the resistance of the valve. In terms of energy conservation, when designing and manufacturing valves, the resistance of the valve to the flowing medium should be reduced as much as possible

opening and closing force and torque opening and closing force and torque refer to the force or torque that must be applied to open or close the valve. When closing the valve, it is necessary to form a certain sealing specific pressure between the opening and closing parts and the two sealing surfaces of the hair seat, and at the same time, it is also necessary to overcome the friction between the valve rod and the packing, the threads of the valve rod and the nut, the support at the end of the valve rod and other friction parts. Therefore, a certain closing force and closing torque must be applied. During the opening and closing process of the valve, the required opening and closing force and torque are changed, Its maximum value is at the final instant of closing or the initial instant of opening. When designing and manufacturing valves, try to reduce their closing force and closing torque

opening and closing speed the opening and closing speed is expressed by the time required for the valve to complete an opening or closing action. Generally, there are no strict requirements on the opening and closing speed of the valve, but some working conditions have special requirements on the opening and closing speed, such as some require rapid opening or closing to prevent accidents, and some require slow closing to prevent water hammer, which should be considered when selecting the valve type

action sensitivity and reliability refers to the sensitivity of the valve to respond to changes in medium parameters. For throttle valve, pressure reducing valve, regulating valve and other valves used to adjust medium parameters, as well as safety valve and drain valve, the automobile transmission shaft change fatigue performance test bench professionally produced by Shandong Sida high-tech mechanical equipment Co., Ltd. adopts the development concept of unitization, modularization and standardization. For valves with specific long-term development functions, its functional sensitivity and reliability are very important technical performance indicators

service life, which indicates the durability of the valve, is an important performance index of the valve and has great economic significance. It is usually expressed by the number of opening and closing times that can ensure the sealing requirements, and it can also be expressed by the service time

type classification of valves according to purpose or main structural characteristics

model number of valves according to type, transmission mode, connection form, structural characteristics, seat sealing surface material and nominal pressure

connection dimensions dimensions dimensions of connecting parts of valves and pipelines

main overall dimensions general dimensions opening and closing height of valves Handwheel diameter, connection size, etc.

connection type of connection various methods used for connecting the valve to the pipeline or machinery and equipment (such as flange connection threaded connection welded connection, etc.

seal test seal test test to inspect the performance of the sealing pair of the hoist and valve body

upper seal test back seal test test test test to inspect the sealing performance of the sealing pair of the valve stem and bonnet

seal test pressure the specified pressure during the sealing test of the valve

suitable medium suitable for the valve

suitable temperature suitable for the valve The temperature range of the medium used

sealing surface sealing face the hoist is closely fitted with the valve seat (valve body), and the two contact surfaces that play the role of sealing

the hoist disc is used to cut off or regulate the flow of medium in the three months up to the end of December, such as the ram in the gate valve, the disc in the throttle valve, etc.

packing packing into the stuffing box (or stuffing box), Packing seat to prevent the medium from leaking from the valve stem. The packing gland is used to compress the packing to achieve the sealing. The support yoke is on the bonnet or valve body, It is used to support the valve rod, which is more difficult to repair than other environmental experimental facilities, nuts and transmission mechanism parts

connection groove dimension of connecting channel hoist and valve rod assembly connection part structural dimension

flow area refers to the minimum cross-sectional area between the inlet end of the valve and the sealing surface of the valve seat (but not the "curtain" area), It is used to calculate the theoretical displacement without any resistance effect

flow diameter corresponding to the diameter of the flow area

flow characteristics under the steady flow state, when the inlet pressure and other parameters remain unchanged, the functional relationship between the outlet pressure of the pressure relief valve and the flow rate

flow characteristics derivation under the steady flow state, when the inlet pressure and other parameters remain unchanged, The change value of outlet pressure caused by the change of pressure reducing valve flow

general valve

valves commonly used in pipelines in various industrial enterprises

automatic valves self acting valves rely on the ability of media (liquid, air, steam, etc.) themselves

actuated valves with the help of manual, electric Hydraulic or pneumatic operated valve

impact handwheel hammer blow handwheel a handwheel structure that uses the impact force to reduce the operating force of the valve

worm gear actuator a device that opens and closes or regulates the valve with a worm gear mechanism

pneumatic actuator a driving device that opens and closes or regulates the valve with pneumatic pressure

hydraulic actuator a driving device that opens and closes or regulates the valve with hydraulic pressure

Hot condensate capacity can discharge condensate in the steam trap I/J under a given pressure difference and temperature; Large weight

steam loss the amount of fresh steam leaking out of the steam trap in unit time

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