Lesson 15- Pump Operation - Drafting Operations

Question 1

What is the difference in elevation between the water level and the center of pump when a pumper is drafting water

Answer 1

Lift

Question 2

at sea level atmospheric pressure

Answer 2

14.7 psi

Question 3

the 10’ drafting suction hose should be considered the minimum and in most cases necessary to have how many lengths

Answer 3

three

Question 4

suction strainer should be submerged at least ___ feet below the level of the water

Answer 4

two

Question 5

the water should be at least ___ feet deep where the strainer is located to provide clearance below and sufficient depth above it

Answer 5

four

Question 6

to secure hard suctions and take weight off the couplings a tie rope is used, what knots are tied

Answer 6

1. clove hitch on one end
2. running bowling on other end

Question 7

Pumps are rated at capacity using __” suction at a __’ lift

Answer 7

6” suction
10’ lift

Question 8

Rotary gear and rotary vane are positive displacement pumps. What does positive displacement mean

Answer 8

pumps capable of displacing air the same as they displace water

*able to create their own vacuum and lift of water

Question 9

Centrifugal pumps are not able to create a vacuum due to the fact that __ can leak through the pump

Answer 9

air

Question 10

In order for centrifugal pumps to be used for draft, they must have

Answer 10

priming pumps or priming devices

*they evacuate air from centrifugal pumps allowing atmospheric pressure to push water up the pump

Question 11

Pumps of 1500 GPM or larger capacity are required to take suction in not over __ seconds

Answer 11

45

Question 12

Reasons you can’t get a prime

Answer 12

1. Prime pumps run in a bath of oil, failure may indicate pump is dry and needs lubrication
2. Air leak
3. high vacuum reading, no water may indicate suction lift is too high or strainers may be obstructed