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close this book A training manual in conducting a workshop in the design, construction, operation, maintenance and repair of hydrams
close this folder Session 5: Review exercise #1 (2 hours)
View the document Handout 5A: Review exercise #1
View the document Handout 5B: Answers to review exercise #1

Session 5: Review exercise #1 (2 hours)


Total Time: 2 hours

OBJECTIVES: By the end of this session trainees will have described how a hydram works, in their own words, solved review problems independently and clarified any misunderstandings to date.

OVERVIEW: This session provides an opportunity for participants to review and synthesize material to date.

MATERIALS: Handout 5A Pencil, paper Chalkboard/chalk or flipchart-markers





Encourage questions on any information that has been presented thus far and try to get trainees to answer for each other.

30 min.


Distribute the review exercise, and ask individuals to complete it on their own.

30 min


After everyone has completed the review exercise, have them discuss answers with one other person.

20 min


Ask for volunteers to share answers to individual problems.

30 min.

Handout 5A: Review exercise #1


1. How does a Hydram work?________________________________________________________

2. In a hydram installation where the hydram is located 20 feet below the spring box, how much water could be pumped in a day to a storage tank 100 feet above the springs' box if the spring is flowing 10 gpm and the hydram efficiency is 50%?______________________________________

3. What is the flow rate in gpm through a weir, four inches wide, when the water level is 5 3/8" above the bottom of the weir slot when measured two feet upstream?_________________________

4. What is the height of your eye level?________________________________________________

5. What is the length of your pace?___________________________________________________

Handout 5B: Answers to review exercise #1

1. The hydram is located below the source of water and is used to pump the water to a storage tank which is higher than the source. The water accelerates as it flows down hill through the drive pipe and out the impulse valve until it reaches such a velocity as to slam the impulse valve shut. This causes a water hammer effect, forcing water and a few air bubbles sucked in through the snifter from the previous cycle, through the check valve and into the accumulator filled with air. This movement of water into the accumulator causes the air to compress until the forward momentum is stopped. At this point the water in the accumulator bounces back because of the spring effect of the air in the accumulator. This rebound in the opposite direction causes the check valve to suddenly close, causing negative pressure in the hydram before the check valve. Because of this negative pressure, air is sucked in through the snifter and the impulse valve is caused to open again at which point water starts exiting through the impulse valve and the cycle starts again.


H - 20

h = 100 + 20 = 120

Q = 10

n = .50

q = Q x H/h x n

q = 10 x 20/120 x .50 = 0.8333 gpm

0.8333 gpm x 1440 min / day = 1200 gpd

3. 5 3/8" on the weir table is 37.25 gpm.

This times four equals 149 gpm.

4. Any answer within reason is OK.

5. Any answer within reason is OK.