Pumps

Question 0

What are two categories of pumps?

Answer 0

1. Non-positive displacement

2. Positive displacement

Question 1

What is the function of a hyd. gear pump?

Answer 1

To create oil flow

Question 2

How do non-positive pumps create flow?

Answer 2

Create centrifugal force to push oil

Question 3

Positive displacement pumps:

Answer 3

Use teeth to seal, and are always building pressure

Question 4

What is pressure rating?

Answer 4

Identifies the maximum pressure a pump can safety withstand without damage

Question 5

What are two basic types of gear common in this industry

Answer 5

1. External gear

2. Internal gear

Question 6

Which port on a gear pump is the larger?

Answer 6

The inlet

Question 7

Unidirectional pumps operate:

Answer 7

In one direction only

Question 8

What is maximum allowable vacuum at pump inlet?

Answer 8

5 in Hg

Question 9

A direct pressure relief valve is;

Answer 9

Normally closed valve that senses pressure

Question 10

What is relief valve cracking pressure?

Answer 10

The pressure at inlet port when ball is moved off of seat.

Question 11

What is full flow pressure?

Answer 11

Pressure required to fully open the relief valve

Question 12

What is Pressure override?

Answer 12

Is the pressure difference between cracking pressure and full flow pressure

Question 13

What are the 3 common control valve configurations?

Answer 13

1. Spool type
2. Rotary type
3. Poppet type

Question 14

What is feathering?

Answer 14

When spool is partially moved making it act like a variable orifice

Question 15

What are most common methods of of valve actuation?

Answer 15

1. Mechanical
2. Pilot
3. Electrical

Question 16

What are the two common types of directional control valve center conditions?

Answer 16

1. Open center

2. Closed center

Question 17

What is difference between open center and closed center?

Answer 17

Open center P is connected to T.

Closed all ports are blocked

Question 18

What are to basic types of hydraulic cylinders are:

Answer 18

Single acting

Double acting

Question 19

Which portion of a telescoping cylinder lifts first?

Answer 19

The largest portion moves first

Question 20

What is volumetric efficiency?

Answer 20

Term used to express the amount of flow lost due to internal leakage.

Question 21

Equation for volumetric efficiency

Answer 21

VE= actual flow rate/ theoretical flow rate