Hydraulic Systems 2 part 1

An actuator at rest powered by a fixed displacement pump can conserve energy if it is controlled by a DCV with a _____ center.

• A. Free float

• B. Tandem

• C. Closed

• D. Open

A typical application of a hydraulic 4/2 DCV is _____.

• A. Where there is a need to allow the actuator to coast to a stop

• B. There is not a need to stop the actuator

• C. In a punch press

• D. All of the above

• E. None of the above

A hydraulic 4/2 DCV with offset P to B _____

• A. Is connected P to A when de-energized

• B. Is connected P to B when energized

• C. Is connected A to T when de-energized

• D. All of the above

• E. None of the above

Three-way, 2 position DCVs (called 3/2 valves) are used to _____.

• A. Control actuator speed

• B. Power actuators in one direction

• C. Power actuators in both direction

• D. Stop actuators in any position

Hydraulic 4/2 DCVs are often used as 3/2 DCVs by _____.

• A. Changing the speed

• B. Blocking a port

• C. Placing the spring on the other end

• D. Changing the operator

Hydraulic pilot-operated DCVs are used in applications requiring high _____.

• A. Efficiency

• B. Pressures

• C. Temperatures

• D. Flow rates

Why are two valves required in an application using a pilot operated DCV?

• A. One valve is needed for each direction

• B. The required force to shift the large valve is too great for a lever or solenoid

• C. One valve is a backup, in case of failure in critical installations

• D. Depending on flow and pressure, the main or pilot valve is used, but not both

A cam-operated 4/2 valve can also be described as a _____.

• A. Deceleration valve

• B. Roller-operated valve

• C. 3-position valve

• D. All of the above

A Cam-operated valve used in a circuit that controls fast approach followed by a decrease in speed is called _____.

• A. Rapid-traverse, slow feed

• B. Sequence

• C. Safety lockout

• D. High-low

Like any other 4/2 DCV, the cam-operated 4/2 DCV can also be used in a 3/2 mode by blocking the port, if the tank port is _____.

• A. Connected back to the pump

• B. Connected through a flow control valve

• C. Connected directly to the tank

• D. Filtered