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48 Cards in this Set
- Front
- Back
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What type of valve controls the speed of the actuator |
The flow control |
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What type of valve controls the force of an actuator |
The pressure control |
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Which pressure control valves are normally closed? |
Relief, unloading, sequence, counterbalance and brake |
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Which pressure control valve is normally open |
Pressure reducing |
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Which valve is the first valve downstream from the pump in a hydraulic system |
Maximum pressure relief valve |
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Who should adjust the maximum pressure relief valve? |
Only qualified personnel |
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List four ways to unload a pump |
Vent the relief Use an unloading relief Connect on on/off valve to tank from the pressure line Use a pilot-operated unloading valve |
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What happens if you do not provide a pilot drain on a sequence valve or a pressure reducing valve? |
They would not operate after a few cycles under load |
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What happens if you install a brake valve on a motor without connecting the pilot to the inlet |
The motor does not turn |
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What three types of elements are used in directional control valves |
Rotating speed Sliding spool Poppet |
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What is meant by a way in a valve |
A passage for the main flow |
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List two ways to use a three-way, two-position directional control valve |
As a diverter To operate a single acting cylinder |
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What is the purpose of the pilot chokes on a directional control valve |
To control the shift speed of the spool |
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How are valves held in their normal positions |
By springs |
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What types of spool centres could you use to allow the cylinder to float |
Open Center, float Center (or motor center |
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What are three flow control methods |
Meter-in Meter-out Bleed-off |
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Do pressure control valves control the speed or the force of an actuator |
Force |
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What is the main purpose of a maximum pressure relief valve |
To relieve the maximum pressure in the system in case of overload |
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What is the purpose of an unloading valve |
To depressurization part of the system or the entire system before the main pressure relief valve opens |
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Would you use a normally open or normally closed valve to relieve the pressure in a system? |
Normally closed |
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What can happen if you set the maximum pressure relief valve above the maximum pressure for which the system is rated |
Serious damage or injury can result |
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What is pressure overide |
The difference between the full flow pressure and the cracking pressure |
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What is the purpose of venting the relief valve |
To unload the system from a remote location |
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Would you use a normally open or a normally closed valve to reduce the pressure in a branch of a circuit |
A normally open valve |
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What happens if a particle of dirt gets caught between the poppet and seat of the reverse flow bypass on a pressure reducing valve |
You are not able to adjust the pressure |
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Would you use a normally open or a normally closed valve to control the sequence of an operation |
Normally closed |
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If the second cylinder in a sequence circuit fails to move after the first cylinder completes its stroke, which troubleshooting technique should you try first? |
Decrease the spring setting on the sequence valve (pressure control valve) |
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Which pressure control valve can be used instead of a counterbalance valve |
A sequence valve |
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What happens if dirt gets between the poppet and seat of the reverse flow bypass on a counterbalance valve |
The load free falls |
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Should you connect the pilot from a brake valve to the inlet or the outlet of a motor |
Brake valves have two pilots. The external pilot is connected to the motor inlet (supply line) and the internal pilot is from the motor outlet |
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Can you operate a double acting cylinder with a three way, two-position directional control? |
No |
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Which flow control method provides the best control when the loading is unsteady? |
Meter-out |
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What is the danger of using meter-out flow control on the rod end of the cylinder if the load pulls on the rod |
Pressure intensification above the safe working pressure of the system |
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What kind of flow control provides the greatest energy efficiency |
Bleed-off |
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Where should you locate a flow control with a reverse flow bypass to control the speed of the actuator in both directions |
Upstream from the directional control valve |
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What kind of flow control valve allows speed control in one direction and full speed in the other direction |
Valve with reverse flow bypass |
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What is the purpose of a pressure compensator on a flow control valve |
To ensure steady flow when the load fluctuates |
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What is the purpose of a temperature compensator on a flow control valve |
To maintain the actuator speed when the temperature changes |
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What is the purpose of the overspeed control feature on a flow control valve? |
To prevent a speed increase if the directional control is suddenly shifted |
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Which type of spool Center do you need if the cylinder must be locked when the spool is in the Center position and the pump flow is to circulate freely back to the tank without going over the relief? |
Tandem center |
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What happens if someone shuts off the pilot chokes |
The main spool would not shift |
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How can you check to determine whether the pilot solenoids are working |
Manually shift the pilot spool to see if the main spool shifts |
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What kind of spool do you need to increase the extension speed of a cylinder |
Regenerative spool |
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What kind of check valve do you need if you want to have a minimum pressure loss in the valve |
A right angle check valve |
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What kind of check valve do you need to lock a double acting cylinder when the directional control valve spool is centered |
A pilot- to-open check valve |
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What kind of check valve do you need to automatically drain an accumulator when the pump is shut down? |
A pilot-to close check valve |
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Does a flow control valve control the force or the speed of an actuator |
Speed |
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What is the safest flow control method (meter in or meter-out) if the cylinder is used for a steady lift with the rod extending |
Meter-in |
