Pumps for Private Water Supply Systems 060401b

Question 1

Name 4 reasons why you would use the centrifugal pump for private water supply?

Answer 1

• the pumps are relatively east to produce
• they can be small and lightweight
• can be adapted to many convenient forms of drive
• they are generally very good at moving fluid

Question 2

What is the maximum theoretical lift of a centrifugal pump?

Answer 2

34 feet

Question 3

What is the maximum practical lift of a centrifugal pump at sea level?

Answer 3

25 feet

Question 4

The practical lift of a suction pump must be reduced by how much for every 1000 feet of elevation difference?

Answer 4

1 foot for every 1000 feet of elevation gain

Question 5

What is variable displacement?

Answer 5

When a pump is asked to do more work in the form of increased height and fluid lift or increased output pressure output from the pump, the amount of water coming from the centrifugal pump reduces

Question 6

As discharge pressure or discharge height increases, a pump cannot move as much water as it would at lower discharge pressure or height due to increased slippage. The pump will still try to move the fluid, but the fluid cannot move away from the pump. What will this cause to occur?

Answer 6

Pump cavitation

Question 7

What 2 factors create the pressure output of a pump?

Answer 7

• the height it can move the fluid

- the relative density of the fluid

Question 8

What can be done when running a line from the wellhead to the pump inlet to allow better air elimination from suction line when priming?

Answer 8

Should grade upward from wellhead to pump inlet

Question 9

What function in the impeller allows gasses to escape the water?

Answer 9

Reduction in pressure at the eye of the impeller

Question 10

In some instances the water from a well may have dissolved gases that come out of it when the pressure is reduced by a centrifugal pump placed in it. What must be done to account for these gasses?

Answer 10

A pressure tank that does not have air/water separation in it may need to be used to allow venting of gases from the supply water

Question 11

What is the usual method of controlling a private water supply pump?

Answer 11

Pressure switch

Question 12

What are the 2 acceptable cut in/cut out pressures for private water supply pressure switches?

Answer 12

20-40 psi or 30-50 psi

Question 13

To prevent undue wear and tear on a pump motor, the run cycle of a centrifugal pump is recommended to be how long?

Answer 13

2 minutes

Question 14

A centrifugal pump on private water supply should not cycle more than how many times per hour?

Answer 14

25

Question 15

What are the 2 different types of reciprocating piston pumps?

Answer 15

• Horizontal reciprocating pump

- Deep-well working head pumps

Question 16

Reciprocating pumps must be protected by what?

Answer 16

Pressure relief

Question 17

The pressure relief valve being used to protect a system using a reciprocating pump is usually set to relieve at how many psi over the cut-out setting?

Answer 17

15-20 psi

Question 18

Reciprocating pumps are often used for what application?

Answer 18

• Low production wells that do not have the water volume or capacity to supply the owners requirements directly from the well
• wells from an aquifer that allows sand to enter the well with water from the aquifer. A centrifugal pump can quickly wear if sand is pumped with the water

Question 19

Diaphragm pumps are often used for what application?

Answer 19

• Moving corrosive material

- often hand operated and sometimes used as fuel transfer pumps or in applications where power is unavailable

Question 20

What is the most common use for a bladder pump?

Answer 20

Used where corrosive or sensitive materials must be pumped. Often used for pumping rather than developing pressure

Question 21

Rotary pumps are similar to centrifugal pumps because the rotary motion of a power source makes the pump turn in a circular manner, but what sets these pumps apart from centrifugal pumps?

Answer 21

Rotary pumps are positive displacement pumps and centrifugal pumps are variable displacement pumps

Question 22

What application would require the use of a gear style rotary pump?

Answer 22

Wet sprinkler systems piped for fire suppression where a pump with low flow is desired but high pressure capability is needed

Question 23

What application would require the use of a helical rotor pump?

Answer 23

Could be used as a suction pump for private water systems, but is seldom encountered in service unless heavy fluids like sludge or slurry applications are in place

Question 24

What application would require the use of a regenerative turbine pump?

Answer 24

Often used for municipal water applications or boosted water pressure systems in high buildings

Question 25

What application would require the use of a peristaltic pump?

Answer 25

Extensively used in the health profession for kidney dialysis

Question 26

Jet pumps are centrifugal pumps that have been adapted by incorporating what 2 things into the inlet of the impeller housing?

Answer 26

A nozzle and Venturi

Question 27

How do you size the suction pipe in a 2 pipe jet pump application?

Answer 27

The suction pipe is usually one size larger than the pump driveline

Question 28

A typical impeller section for a submersible pump will generally increase water pressure available from the impeller by how much?

Answer 28

9 psi per stage

Question 29

You should avoid using this to secure wiring in a submersible well pump application

Answer 29

Electrical tape

Use zip ties

Question 30

The delivery capacity of a pump must be…

Answer 30

Equal to or less than the amount of water available to the well from the aquifer

Question 31

Centrifugal pumps used as suction pumps are limited to a practical suction lift of how many feet?

Answer 31

15 to 20 feet

Question 32

Centrifugal jet pumps used for suction are limited to how many feet of lift?

Answer 32

20 to 25 feet

Question 33

Centrifugal jet pumps used for deeps wells is usually limited to depths of approximately how many feet?

Answer 33

180 feet

Question 34

A submersible pump may be capable of developing pressure greater than the components of the system can handle and may require the addition of a pressure relief set at how many psi above cut out pressure?

Answer 34

10 psi

Question 35

A clear water sump pump often has what kind of impeller?

Answer 35

Closed impeller

Question 36

A sump pump used for subsurface drainage may only need a pump with what kind of impeller?

Answer 36

Semi-open

Question 37

A sump pump used for a dewatering application around construction sites may require a pump with what kind of impeller ?

Answer 37

Open impeller to move relatively large solids through the pump

Question 38

Residential pump sizing is based on what?

Answer 38

Seven minute peak demand period that may occur 2-3 times a day

Question 39

Agricultural pump sizing is based on what?

Answer 39

Two hour peak demand period that may occur twice a day

Question 40

To properly size the drop pipe and supply pipe to a house requires detailed calculation of what factors?

Answer 40

• pipe lengths
• number of fittings
• flow rate of system
• elevation difference
• desired pressure

Question 41

Most residential submersible pumps are installed with what size of drop pipe and supply line to the house?

Answer 41

1” and in rare instances 11/4”

Question 42

When is a well considered a deep well?

Answer 42

When the wells pumping level is greater than 24 feet

Question 43

How may drawdown in a well effect an aquifer?

Answer 43

Drawdown can allow the aquifer to start releasing sand

Question 44

What type of piston pump can be offset from the top of a well?

Answer 44

Shallow well piston

Question 45

When a shut off valve is placed on a tank tee in a residential application, which side of the tank tee should it be placed on?

Answer 45

Outlet of tank tee