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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 Guidelines for users
close this folder Construction of a PVC hydram time: 4-5 hours (for demonstration purposes)
View the document Attachment A : PVC Hydram - illustration

Construction of a PVC hydram time: 4-5 hours (for demonstration purposes)


To construct a hydram from clear PVC pipe-fittings and fabricated valves.


The PVC hydram is an excellent training tool because it enables trainees to see the hydram components moving while the ram is in operation, and to observe the directional flow of water as shown by suspended solids in the water. The PVC hydram is of limited use for actual water pumping, however, as it will last only about one month in continuous use. For this reason, it is suggested that one or more PVC hydrams be constructed prior to the workshop, and used to illustrate the introductory sessions (Session 1 & 2) on the first day Of the workshop itself. The construction could be part of a pre-workshop staff training program, if desired.


2 1¼ tees

1 ¼%" coupling


1 3/4" male adapters

4 ½ #6 sheet metal screws


1 1¼" cap

2 1"x ¼ x 20 bolts


1 14"x 1¼" pipe

1 2"x ¼ x 20 bolt


5 1¼"x 3/4" reducing


6 ¼ x 20 nuts

assorted washers


1 24"x 3/4" pipe



PVC cleaner, PVC glue, 1/8" sheet rubber, TFE tape


Heat source (such as propane torch, campfire, oven) ¼-20 tap, saw, miter box, electric or hand drill, 1/8" drill bit, 13/64" drill bit, screw driver, 7/16" wrench or adjustable wrench, knife, tape measure


This is presented in session format, in case it needs to be done with all participants, in addition to trainer preparation.





Warm up the middle 12" of the 24" long 3/4" PVC pipe, making sure it is heated evenly without scorching or blistering. After PVC is pliable bend it into a 90° angle with about a 5" to 6" radius. Allow it to cool, then cut 5" off each end. (See #3 and #8 on Attachment A.



Cut the 1¼" PVC into two pieces, one 12" long (#6) and one 2" long (#19), making certain that the ends are cut square and are de-burred.



Cut the 1¼" coupling (#13) into two cylindrical Pieces just to one side of the land. Cut of the bottom of one of the 1¼"x 3/4" reducing bushings, and sand it smooth on both sides to form a 3/8" thick PVC washer (#14), Glue the washer inside the piece of coupling without the land, flush with one end. Discard the other half of the coupling and the remainder of the bushing.



To make the valves, cut two circular pieces of rubber to the same outside diameter as the 1¼" PVC pipe. Cut out of each round a horseshoe shaped piece and a ¼" hole as shown in Attachment A#7.



Place four wraps of TFE tape around Note the 2 types of 1¼" PVC pipe. Lay on top of this one of the rubber valves you have cut out. Handout. Force this into the coupling half that has the PVC washer glued into it. Attach bolt (#12), nuts (#10) and washers (#15 & #16) as shown in Handout. Drill two 1/" holes (one on each side) through this impulse valve assembly and into of the 2" piece of 1¼" PVC. Then screw two sheet metal screws into these holes (#18).

Note the 2 types of stroke adjustment t illustrated in the handout. That labeled "alternate" is slightly more complicated to construct but provides easier adjuster. Materials required for the alternate stroke adjustment E .

¼ x 20 bolt and nut

½" wide x 2" long piece cut from PVC pipe

2½ #6 sheet metal screw


Cut ¼" off the bottom straight through leg of one of the tees (#1), making certain the cut is square and de-burred. Place four wraps of TFE tape around the male end of a 1¼" x 3/4" reducing bushing. Attach the 1" x ¼" bolt with nuts and washers to the remaining rubber valve as shown in the handout. Then place this rubber valve inside the bottom of the tee you just cut off. Force the TFE wrapped reducing bushing up to the rubber valve. Drill two 1/8" holes into this assembly and secure with 2 sheet metal screws.



Next, glue the rest of the pieces together as shown in the Attachment. Be sure to follow the instructions on the glue.



Drill a 13/64" hole through one of the flats on the reducing bushing just below the check valve, making certain that you also drill through the 3/4" pipe as well. Drill a 1/8" hole up from the bottom of this bushing, intersecting with the 13/64" hole. Tap the 13/64" hole with a ¼-20 tap then insert a 3/4" ¼-20 bolt with lock nut (#9 & #10).



After the hydram(s) have had time to dry, hook them up to a drive head and test them.