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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 10: Hydram construction - concrete (18 hours over a 7 day period)
View the document Handout 10A: Concrete hydram design parameters
View the document Handout 10B: Thickness of the impulse valve plate - inches
View the document Handout 10B: Thickness of the impulse valve plate - metric
View the document Handout 10C: Impulse valve steel backing - inches
View the document Handout 10C: Impulse valve steel backing - metric
View the document Handout 10D: Impulse valve seat width - inches
View the document Handout 10D: Impulse valve seat width - metric
View the document Handout 10E: Check valve backing thickness - inches
View the document Handout 10E: Check valve backing thickness - metric
View the document Handout 10F: Check valve seat width - inches
View the document Handout 10F: Check valve seat width - metric
View the document Handout 10H: Exploded view of 2- piece concrete hydram
View the document Handout 10I: Side view 2-piece concrete hydram
View the document Handout 10J: Two piece concrete hydram form
View the document Handout 10K: Two piece concrete hydram
View the document Handout 10L: One Piece Concrete Hydram Form
View the document Handout 10M: Problem
View the document Handout 10N: Materials and procedures

Session 10: Hydram construction - concrete (18 hours over a 7 day period)

Time: 18 hours over a 7 day period


· to design and build a concrete ram

· to demonstrate a knowledge of ram component relationships;

· to work with concrete and forms.

OVERVIEW: The session provides participants with an opportunity to use the knowledge gained earlier in the training program to assess site potential, determine an appropriate hydram size and design and then construct an inexpensive, long lasting concrete hydram. While building a concrete hydram necessitates scheduling a lengthy session over at least seven days, the advantages of this technology (i.e., low cost, excellent longevity, likely availability of materials) make this one of the most useful parts of a hydram training program.

PREPARATION NOTES FOR TRAINER: When possible, the concrete hydram(s) should be built at a site where it can be of use after the training program is over. Trainers should there fore gather data about community need, end-uses etc. unless extensive time is available for trainees to do this. The timing of the various construction phases will be somewhat dependent on the mixture of the concrete and the ambient temperature. In general, the building of a concrete hydram will require four segments of time with a minimum of 2 days between segments. The first phase requires approximately 4 hours for steps 1-9 (planning) and 4 hours for steps 10-19 (base form construction and the first pour). The second phase should occur at least 48 hours later and should take about 4 hours for steps 20-27 (accumulator form construction and 2nd pour). After another 48 hours or so, the concrete should be sufficiently set up for steps 28-35 (fabrication and attachment of valves, bolting the hydram together). In general, the hydram should be ready for steps 36-38 (installation and operation) after 2 more days, or four days from the last pour.

Trainer should check porosity of concrete prior to this activity.

Hand outs B-F are in metric and English units. Use of slides greatly enhances concrete construction preparation session.

MATERIALS: gravel, sand, cement, water, form lumber, plastic pipe, bowl, fittings, material for vapor barrier something to mix cement in. Size and quantity of materials is dependent upon the hydram to be constructed. Following is an example of a typical list of materials for a 1" hydram.


1 1"x 12"x 8' lumber for body

8 3/8 althread 36" form

1 1"x 12"x 8' lumber for accumu-

26 3/8 lock washers lator forms

1 ¼" x 7" diameter steel plate

26 3/8 flat washers

1 3" PVC pipe cap

26 3/8 nuts

1 4" bowl

1 1" pipe plug

1 1'x 1' x ½ belting

1 1" pipe tee

1 7" diameter x ¼" belting

1 ¼" pipe plug

1 1"x 2" angle 1" long

1 ¼" pipe tee

1 rubber stop bumper

1 ¼" pipe plug

1 ¼" gas cock

1 ¼" pipe tee

1 1" PVC pipe 2' long

2pcs. ¼" pipe 2" long

1 ¼" nipple 1½" long

1 1" PVC male adaptor

2 2½" washer with 3/8" hole

1 ¼" PVC pipe 22' long

2 1½" washer with 3/8" hole

1 1" PVC coupling

5/16" wing nut

½ lb 6d nails

1 5/16 x 2½" bolt

form oil

2 ¼ x½ bolt

2½ gal water

3 5/16 nut

32# cement

1 3/8 bolt 1" long

1 1/3 cu.ft. gravel

1 3" PVC pipe 18" long

1 1/6 cu.ft. sand

Handouts 10A-10N







Phase I: Part One



State the objective of this session.



Have the trainees gather all pertinent information concerning the hydram installation including drive head, delivery head, flow rate at source, demand, future needs, and portability.



Describe the concrete hydram concept and the design parameters involved.



Review the advantages and disadvantages of this design.



Walk through design steps, using handouts 10A - I. Write on board/flip-chart as developed.

Trainer should plan how to display this on chalkboard.




A. Concrete: (handout 10A)


1. Compute D.


2. Compute impulse valve cavity diameter.


3. Compute wall thickness.


4. Top and bottom thickness.


B. Size Impulse Valve Opening (2D)

Remind trainees that: this is related to drive head, force.


1. Use attachment 10B to determine thickness of valve plate.


2. Use 10A to determine bolt area and number of bolts.


3. Use 10C to determine backing thickness.


4. Use 10D to determine seat width.


C. Size check valve

Relate this to drive pipe size as basis for calculations.


1. Use 10E for backing thickness.


2. Use 10F to determine seat width.



Have the trainees each design a hydram, using the design parameters listed in Handouts A through I. Have the participants solve the problem in attachment/handout 10M.



Compare designs and discuss the differences.



Depending on how many hydrams are to be made, the trainees should choose the best design(s) and explain why they have made their choice.



Give an overview of construction process and scheduling in the workshop:

This may be hard for trainees to visualize. A model would be helpful; slides are also effective, and may be procured through the Energy Sector, Peace Corps.


Phase I:


A. Build forms, using pipes, cups, form lumber, as in Handout 11H-J.


B. Note where/why sleeves are inserted; where # comes from.


C. Make sure snifter is included.


D. Mix and pour concrete.


E. Protect and let it set up for at least 2 days.


F. Draw pattern for impulse valve plate.


Phase II:


A. Construction of accumulator form.


B. Pour accumulator.


C. Let it set up.


Phase III-IV:


A. Cut check valve, assemble and install.



Distribute procedures for Phase I. Ask trainees to read through. Clarify any questions.



Have the trainees make up a material and tool list for the hydram(s) selected.



With all the tools and materials gathered, begin construction.


Phase I - Part Two



Start by constructing the hydram base form. (See handout 10J)



Next, bend the PVC pipe and cut to proper length and angles. Be sure to glue a coupling to the check valve end to increase the seat area.



Notch out bottom of plastic bowl to fit upon the PVC pipe: with the bowl and pipe held together, mark where the pipe touches the inside of the bowl; then, using coping saw, cut along this line. Attach male adapter and the plugged tee to input end of pipe. The plugged tee serves to prevent the pipe from turning within the concrete. Welding a piece of metal onto the coupling would also work.



Drill holes in the bottom of the form for the bolt pattern around the impulse valve and the accumulator.



Center accumulator form pipe on the inside of the form and draw a circle around it. Drive three 6d nails one half way in, 120 degrees apart through the circle, making compensation for the thickness of the accumulator form pipe.



Drill hole in PVC pipe for snifter. Drill another hole in form for the other end of snifter. Snifter pipe should have a plugged tee in the middle or a piece of metal welded to the side of it to eliminate turning.



An elliptical rubber washer should be cut out and nailed where the check valve end of the PVC pipe comes in contact with the form. This is to recess the concrete around the check valve seat to insure a good seat.



Bolt sleeves to form using althread, nuts and washers.



Tie PVC pie down to form using tie-wire.



Pour the base of the hydram using the following concrete formula: 8 parts gravel, 7 parts sand, 2 parts cement, and water to proper consistency. Tap on the form sides while pouring to prevent air pockets. Cover concrete with a vapor barrier such as visqueen, then cover entire pour with insulation. Draw pattern for impulse valve plate and send to metal shop.


Phase II



After the hydram base has had sufficient time to set (usually about 2 days), remove form and place hydram base right side up on blocks so that the bolt holes on the bottom can be reached.



Place a sheet of plastic or wax paper or anything that will prevent a concrete marriage and that won't wrinkle on top of the accumulator end of the hydram.



Place althread and sleeves through bolt pattern at accumulator with nuts and washers on both ends. Tighten until sleeves are rigid.



Build form for accumulator as shown in Handout 10J.



Place accumulator form pipe over the three nails sticking up through the concrete at the check valve. Pack with sand to prevent pipe from floating up in concrete. Cap end of accumulator form pipe with tape or PVC cap.



Place accumulator form on top of hydram base and install the delivery pipe connection between this form and the accumulator form pipe.



Pour accumulator form full of concrete using the same mixture ratio as used in step #22.



Cover with a vapor barrier such as visqueen and insulation.


Phase III



After concrete has had sufficient time to set up (about one to two days), remove form.



Using a large piece of paper, make a pattern from the hydram base for both the impulse valve rubber and the accumulator check valve rubber.



Cut out the rubbers according to the pattern. If the rubber is too thick to allow free movement of the valves, a notch may need to be cut into the rubber at the flex point of the valve.



Drill and cut out a piece of sheet metal for the impulse plate and attach stop bracket.



Install althread, bolt, nuts and washers on both pieces of rubber as shown in the attachment.



Bolt accumulator to base with check valve rubber for a gasket.



Bolt impulse valve rubber and plate to hydram base.



Install stroke adjustment bolt locknut and rubber bumper.


Phase IV



Install ram to drive pipe and delivery pipe. Start up. Adjust for amount of flow available.



Have the trainees determine the flow rate into and out of the hydram and determine the efficiency.



Discuss with the trainees what they feel the advantages and disadvantages of this ram might be and when they might be important.