Hydraulics review unit1-3

What happens when the resistance to fluid flow in a circuit increases?

• The pressure builds up.

• The pressure decreases.

• The flow rate increases to overcome the resistance.

• None of the choices here.

What happens to a pressure-relief valve as the pressure upstream of the

valve increases? The pressure-relief valve:

• opens when the flow rate reaches a certain value, allowing fluid flow.

• closes when the flow rate reaches a certain value, preventing fluid flow.

• opens when the pressure approaches its pressure setting, allowing fluid

  flow.

• closes when the pressure approaches its pressure setting, preventing

  fluid flow.

Which components are combined within a one-way flow control valve?

• A relief valve and a flow control valve.

• A flow control valve and a check valve.

• A check valve and a pressure regulator.

• A pressure regulator and a flow control valve.

The pressure drop across a flow control valve decreases if

• the valve opening decreases.

• the pressure upstream of the valve increases

• All of the choices here.

• None of the choices here.

Which of the following statements is true?

• Flow regulating valves maintain a constant flow rate for most of their

  pressure range, while flow control valves do not.

• Flow control valves maintain a constant flow rate for most of their

  pressure range, while flow regulating valves do not.

• Flow regulating valves can maintain a constant flow rate in the lowest

  pressures of their pressure range, while flow control valves cannot.

• Both flow regulating valves and flow control valves maintain a constant

  flow rate for most of their pressure range.

The main purpose of a pressure-reducing valve is to reduce the pressure

• downstream of the valve.

• upstream of the valve.

• in a circuit.

• None of the choices here.

In a given hydraulics circuit, the pump pressure is set to 80 bar (1160 psi),

while the pressure-reducing valve is set to 30 bar (435 psi). If the pressure of

the pump increases to 100 bar (1450 psi), what happens to the pressure

downstream of the pressure-reducing valve?

• It increases to 100 bar (1450 psi).

• It remains at 30 bar (435 psi).

• increases to 80 bar (1160 psi).

• None of the choices here.

The devices used to shift the spool of directional control valves are called

• valve controls.

• valve actuators

• valve pilots.

• levers

Increasing the tension in the spring of a pressure-reducing valve:

• increases the maximum pressure downstream of the valve.

• decreases the maximum pressure downstream of the valve.

• causes the pressure-balancing piston in the valve to slide and allow fluid

  flow from port A to T.

• None of the choices here.

When selecting a flow regulating valve for an application requiring a constant

flow rate, make sure the

• flow regulating valve has a much higher flow allowance than the rest of

  the circuit.

• precision of the flow regulating valve is maximal.

• flow regulating valve is located downstream of the directional control

  valve.

• operating pressure is located well within the constant flow rate range of

  the valve.