A.maintain a preset pressure on the line
B.closely regulate the amount of flow
C.relieve excessive pressure on the line
D.allow flow in one direction only
您可能感興趣的試卷
你可能感興趣的試題
A.insufficient load
B.excessively high oil viscosity
C.relief-valve pressure setting too high
D.reservoir level being maintained two inches above normal
A.a defective or broken high pressure un-loader
B.a loose valve plate
C.excessive overload
D.no compression
A.regulating the oil flow with the six-way valve
B.moving the automatic differential valve
C.moving the receiving tele-motor which regulates the two-way valve
D.varying the angle of a tilting box or eccentricity of a floating ring
A.Pour point
B.Cloud point
C.Vacuum
D.Pressure
A.set for maximum torque
B.on the purge and vent stroke
C.in the neutral position
D.rotating backwards
最新試題
Which of the listed pumps is NOT a positive displacement pump?（）
If the thermal bulb of an expansion valve is incorrectly placed at the center of the coil instead of the end, it will （）.
A gradual decrease in the discharge pressure of an operating hydraulic pump can be caused by （）.
One cause of high head pressure occurring in a refrigeration system can be （）.
An excessive charge of refrigerant in an air-cooled refrigeration system can cause （）.
The usual symptoms of cavitation in a centrifugal pump is （）.
The output volume of a positive fixed displacement pump can be changed only by （）.
A pressure drop through the refrigerant liquid line may cause （）.
An internal bypass is provided on some hydraulic system suction strainers to help reduce the possibility of （）.
A salinity indicator is used to determine the （）.