Valve knowledge examination
Selection
Valves are an a attachment and control parts of the fluid delivery system。
A. Pipe b, pump c, boiler d, fluid
Valves can be divided into ds according to the generic classification。
Vacuum valves, low pressure valves, medium pressure valves, high pressure valves, ultra high pressure valves
High temperature valves, constant temperature valves, low temperature valves, ultra low temperature valves
Metal valves, non-metal valves, metal valve liner valves the door
Gate valves, cut-off valves, stop-valves, ball valves, butterfly valves, regulating valves, safety valves, etc
Valves have the ability to cut, connect, regulate, direct, stop, steady pressure, divert, discharge, spill, etc. Of which valves in category a account for 80 per cent of total valve use。
A. Interception and connection class b, reconciliation and containment class c, flow and diversion class d, pressure and discharge category
The valves have six basic closure structures, all of which are derived from them. They are b。
Interception, diaphragm, lock, spherical, butterfly, vertebrae
Gates, truncheons, entanglements, butterflies, ball formations, slide valves form
Fluttersty, plume, vortex, slide valve, door-to-door, gravity
Circumpolar, door-to-door, spring, plume, butterfly, spherical
In recent years, due to the increasing awareness of the environment, the use of b for valve seals, gaskets and fillings has been explicitly banned in our ggb standard and replaced by fillings and seals。
Fluorinated plastics, asbestos, graphite
Asbestos, graphite, bellows
Bone, graphite, rubber
Rubber, graphite, bellows
Polytetrafluoroethylene material is often used for valve seals, mainly because of his advantage c。
High-temperature, high-pressure, chemically stable and non-toxic。
(c) low-temperature, high-pressure, no toxic side effects, price economy。
Self-moluting, chemical stability, price economy。
Self-moluting, high-temperature pressure, easy to shape。
The medium temperature of the valves, with a breech rubber as a sealed valve, cannot be higher than a。
A, 80 °c b, 120 °c c, 200 °c d, 450 °c
The model for industrial valves is based on standard b, which specifies the model and name of the valves。
Gb/t12237 b, jb/t308 c, dg20592 d, gb/t1048
W in valve model z41w-16p dn200 means c。
Valve material is wcb
The valve is sealed with a bellow pipe
Sealed valves manufactured directly from valve materials
Sealed valve material is stainless steel
10. The shell test pressure of the valves is typically the public pressure of the valves and the sealed performance test pressure is typically the public pressure of c。
A, two times b, two times c, d
The medium temperature of a butterfly valve of d343f-16 dn800, of type 11, cannot normally exceed a。
A, 130°c b, 200°c c, 300°c d, 425°c
Type 12, y43h-16c dn100 is c。
A. Liquid automatic valve b, 100 mm common diameter valve
C. Depressure valve d with a common diameter of 100 mm valve
Valves 13, d373f-10 dn250 indicate a connection mode of b。
A, french butterfly valve b, mixed butterfly valve c, french bottom valve d, welded butterfly valves
Under various conditions, the valve is widely used, and one of the advantages below is that it is not。
A. The structure is relatively simple and the casting process works well。
B. Short length of structure, rapid release time and low level of release。
C. Fluid resistance is smaller and the full-time seal surface is less affected。
D. There are no restrictions on the direction of the flow of the medium within the valve。
15 the valve is connected to the pipe by c。
A, pairing, bi-french, welding, welding, screwdriver。
B, pairing, bi-french, welding, welding, screwdriver。
C. Matching, bi-french, yes
