Pump Construction

Part of Water Systems

When gravity cannot deliver water to where it is needed, pumps provide the mechanical force to move water uphill, out of wells, or through pressurized distribution systems. From simple hand-operated lift pumps to self-powered hydraulic rams, pump technology makes water available regardless of terrain.

Types of Pumps

Pump Type	Power Source	Lift Capacity	Complexity
Suction (lift) pump	Hand, animal	Up to 8 meters (theoretical max)	Simple
Force pump	Hand, animal, steam	Unlimited (with enough pressure)	Moderate
Chain pump	Hand, animal, water wheel	Any depth	Simple
Hydraulic ram	Water flow (no external power)	5-50 meters above source	Moderate
Centrifugal pump	Engine, motor, water wheel	Moderate (depends on speed)	Complex

The Suction Pump (Lift Pump)

The most common hand pump for wells, and the simplest to build.

How It Works

A piston moves up and down in a cylinder positioned above the water source. When the piston rises, it creates low pressure (partial vacuum) below it, and atmospheric pressure pushes water up the suction pipe into the cylinder. When the piston descends, a valve in the piston opens, allowing water to pass above it. On the next upstroke, the piston lifts this water and discharges it through the spout.

The 8-Meter Limit

A suction pump cannot lift water more than about 8 meters (26 feet) at sea level. This is not an engineering limitation — it is a physics limitation. Atmospheric pressure can only support a water column approximately 10.3 meters tall, and practical pump losses reduce this to about 8 meters. For deeper wells, you must place the cylinder down inside the well near the water level, or use a different pump type.

Construction

Cylinder:

1. Use a section of cast iron pipe, bored copper tube, or PVC pipe (if salvageable).
2. For hand-made: bore a section of hardwood (elm or oak) to create a smooth cylinder. Alternatively, use a rolled and soldered sheet metal tube.
3. Internal diameter: 50-100 mm for a domestic hand pump.
4. Length: 300-500 mm.

Piston:

1. Turn a wooden disc or cast a metal disc to fit the cylinder with approximately 1 mm clearance per side.
2. Wrap the piston circumference with greased leather (traditional) to create a seal:
   • Cut a disc of thick leather 10 mm wider than the cylinder bore.
   • Attach to the piston body with a washer and bolt, with the leather edges cupping upward.
   • The leather flexes to seal during the upstroke and opens to pass water during the downstroke.
3. Install a foot valve (check valve) in the piston — a simple flap valve or ball valve that opens upward only.

Foot Valve (at bottom of suction pipe):

1. Install a second check valve at the bottom of the suction pipe (where it enters the water).
2. This valve opens upward when the piston creates suction, allowing water in.
3. It closes when the piston descends, preventing water from flowing back into the well.
4. Simple construction: a flat leather disc hinged on one side over the pipe opening.

Handle and Linkage:

1. Mount a lever handle (iron or hardwood) on a pivot above the pump.
2. Connect the handle to the piston rod via a linkage.
3. The handle provides mechanical advantage: a 4:1 lever ratio means the operator pushes with one-quarter the force needed to lift the water directly.

Component	Material Options
Cylinder	Bored hardwood, cast iron, copper tube
Piston	Hardwood disc with leather seal
Piston rod	Iron rod or straight hardwood dowel
Check valves	Leather flap on brass hinge, or ball and seat
Handle	Wrought iron or hardwood lever
Suction pipe	Bored log, clay pipe, or metal pipe

Priming the Pump

A dry suction pump will not create enough vacuum to pull water up. Pour water into the top of the pump before first use (priming) to fill the suction pipe and wet the piston leather. If the pump loses its prime frequently, check for air leaks in the suction pipe joints or a worn piston seal.

The Force Pump

A force pump delivers water under pressure, allowing it to push water above the pump, not just to the spout level. This is essential for pressurized distribution systems and for pumping water into elevated storage tanks.

Construction Differences from Lift Pump

1. The cylinder is sealed at the top — the piston rod passes through a packed gland (stuffing box).
2. Instead of a spout at the top, a discharge pipe exits the cylinder wall, fitted with a check valve that opens outward.
3. On the upstroke: water fills the cylinder through the foot valve (same as lift pump).
4. On the downstroke: the foot valve closes, and the piston forces water out through the discharge pipe under pressure.

Double-Acting Force Pump

For continuous flow (instead of the pulsing delivery of a single-acting pump):

1. Use a cylinder that is sealed at both ends with check valves at each end.
2. Water is admitted and discharged alternately from each end of the cylinder.
3. The result is water flow on both the push and pull strokes.
4. Adding an air chamber (a sealed dome on the discharge side, half-filled with trapped air) smooths the pulsations into a steadier stream. The trapped air compresses during the pressure pulse and expands between pulses, evening out flow.

The Chain Pump

A chain pump lifts water from any depth by pulling a continuous chain of discs through a vertical pipe.

Construction

1. Install a vertical pipe from the water source up to the discharge point. Bore diameter 75-100 mm.
2. Make the chain — a loop of rope or chain with flat wooden or leather discs attached every 20-30 cm. Each disc fits snugly inside the pipe.
3. Route the chain through the pipe from bottom to top, over a wheel at the top, back down outside the pipe, and under a wheel or roller at the bottom.
4. Turn the top wheel by hand crank, animal power, or water wheel. As the chain moves upward inside the pipe, each disc lifts a column of water between it and the disc below.

Advantage	Disadvantage
No depth limit — works at any depth	Requires continuous power input
Very simple mechanism	Discs wear and need frequent replacement
Can be powered by water wheel or animals	Lower efficiency than piston pumps
No priming needed	Chain and discs are labor-intensive to make

The Hydraulic Ram Pump

The most elegant pump design — it uses the energy of flowing water itself to pump a portion of that water to a higher elevation. No external power source needed.

How It Works

1. Water from a stream or spring flows through a drive pipe into the ram.
2. The flow accelerates through the drive pipe and slams a check valve (the waste valve) shut.
3. The sudden stop creates a water hammer pressure spike.
4. This pressure spike forces a small amount of water through a second check valve into a pressure chamber and up the delivery pipe.
5. The pressure drops, the waste valve reopens, flow resumes, and the cycle repeats automatically — typically 30-100 times per minute.

Construction

Drive pipe: The supply pipe from the water source. Length should be 5-10 times the vertical fall from source to ram. Diameter 25-75 mm depending on desired output.

Waste valve: The key component. Must slam shut quickly and reopen reliably.

1. A heavy brass or iron disc seated on a machined opening.
2. The disc is free to move vertically on a guide pin.
3. When water flow reaches sufficient velocity, drag force lifts the disc and closes the valve.
4. A spring or weight bias keeps the valve slightly open at rest so flow can restart.

Delivery valve: A simple check valve (ball and seat, or swing flap) between the ram body and the air chamber.

Air chamber: A sealed dome (3-10 liters volume) that traps air above the water. The air cushions the pressure spike and provides continuous delivery pressure between cycles.

Delivery pipe: Runs from the air chamber to the elevated destination.

Performance

Drive Pipe Fall (m)	Delivery Height (m)	Efficiency	Water Delivered (% of drive flow)
1	5	60%	~12%
2	10	60%	~12%
3	20	50%	~7.5%
5	30	45%	~7.5%

Rule of thumb: A hydraulic ram delivers about 10% of its drive water flow to a height about 10 times the drive pipe fall, running 24/7 with no fuel, no electricity, and no human attention.

Site Requirements

A hydraulic ram needs: (1) a water source with at least 1 meter of fall to the ram location, (2) minimum flow of 5-10 liters per minute through the drive pipe, and (3) a destination no more than about 15-20 times the fall height above the ram. Even small streams can power a ram — it wastes most of the water (the 90% that exits through the waste valve) but the 10% it delivers runs without any other energy input.

Installation and Testing

General Principles

1. Suction pipes must be airtight — even a small air leak on the suction side destroys pump performance. Test by pressurizing the suction pipe and checking for bubbles.
2. All valves must seat cleanly — test by pouring water into the valve and observing whether it leaks through. Lap valve seats against valve faces until watertight.
3. Lubricate leather seals with tallow or grease at installation and periodically during use.
4. Protect from freezing — insulate or drain pumps and exposed pipes before winter.

Common Mistakes

1. Placing the suction pump too far above the water — beyond 8 meters vertical, no amount of pumping will raise water by suction. Measure carefully and place the cylinder within 6-7 meters of the water surface for reliable operation.
2. Air leaks in suction pipe — the most common cause of pump failure. A single loose joint on the suction side breaks the vacuum. Test every joint under pressure.
3. Worn piston leather — leather seals dry out and crack if the pump sits unused. Re-grease or replace leather seals annually.
4. Undersized air chamber on force pumps and rams — too small an air chamber results in pulsating delivery and pipe-damaging water hammer. Size the air chamber at 10-20 times the single-stroke volume.
5. Ignoring check valve maintenance — debris lodged in a check valve prevents it from seating. Install screens at water intakes and inspect valves regularly.

Summary

Pump Construction — At a Glance

• Suction (lift) pumps are simplest but limited to 8 meters of lift — a physics constraint, not an engineering one
• Force pumps deliver water under pressure for elevated tanks and pressurized distribution
• Add an air chamber to force pumps to smooth pulsating output into steady flow
• The hydraulic ram pump uses flowing water’s energy to pump 10% of the flow to 10x the fall height — no external power needed
• Chain pumps work at any depth and are suited to animal or water-wheel power
• Leather piston seals must be greased regularly; worn seals are the most common cause of poor pump performance
• All suction-side connections must be perfectly airtight — test under pressure before operation