Leverpumps were designed to supply divers with compressed air to depths up to 20 to 25 meters / 75 feet. There are some models with only one horizontally positioned cylinder. Some models have two horizontally positioned cylinders but most lever pumps have two cylinders that stand vertical and that move over a fixed point in the middle. The pistons move "up and down" or "there and back" in the cylinders. The upper part of the cylinders was beaker-shaped with the purpose to hold cooling-water. Some companies (like Draeger) fitted the stand in between with an air-cleaning device. Compressed air was lead through the air-cleaner first to clear the air from dust, oil and leather particles before it was lead to the diver. The stand in between was also fitted with a depth-pressure gauge. 

Pump capacity

Like with a car engine, the pumps capacity depends on the content of the cylinder(s). Take the internal radius in inches of the pump piston, sqare it, and mulitly by 3.14. This gives you the cylinder bore. Multiply this times the inches the piston travels in compressing the air (stroke) giving you the total volume of air compressed per stroke of a single piston. Multiply this by the number of cylinders used in one stroke. Multiply by the number of strokes you make in one minute. This gives you the air capacity of your pump in one minute at surface pressure.

The deeper a diver goes, the more the air being delivered to him shrinks in volume. As depth is increased , the surface pump must handle greater volumes of air as well as greater pressures. Every pump has a maximum capacity in cubic feet per minute. This means that there is a certain depth for every pump beyond which it is dangerous to dive with it. Therefore, air requirements set a depth limit on all dives.

We use the following rule of thumb: a diver needs 1.5 cubic feet of free air to breath at the surface. In 10 meters/33 feet pressure has doubled, meaning that 3 cubic feet of air has to be pumped down to deliver the minimum of 1.5 cubic feet at that depth. Small pumps cannot meet this demand. The air entering the helmet has two functions:

The deeper the (shallow water) dive, the larger pump capacity is needed, the more strokes per minute have to be made. If you intend to use a shallow water pump, make sure it is in excellent working condition and you do not exceed 10 meters/33 feet. If you are not exactly sure what you are doing, contact the HDS or a Working Equipment Group near you, BEFORE you dive. 

One cylinder pumps


One of the nicest pumps we have ever seen. Morse 1 cylinder shallow water pump # 4, probably made prior to 1905. 
Photo courtesy of Bob Croot.

Two cylinder pumps

Miller Dunn

Miller Dunn from Miami, Florida produced beautiful diving equipment. Have a look at this #1 two cylinder lever pump. Also referred to as the "Wobble Pump". The one on the left badly needs attention. The one on the right is beautifully restored and acompanied by Miller Dunn style #2 (right) and style # 3 (left) helmets. Used by the US Navy for a long period of time. A reliable pump with a small capacity. Photo courtesy of Bob Croot.  


Morse #12 shallow water pump. A two cylinder single-acting pump with a somewhat larger capacity that the Miller Dunn #1. One crank-shaft moves two cylinders "there and back" after each other. Photo courtesy of Argonout Traders. 

A nicely polished Morse #15 shallow water pump. The picture on the right is taken from below and shows you the rugged and simple design of this pump. The handle operates the crank-shaft. Designed to work together with the Morse #15 shallow water helmet. The light weight made it ideal for use in small boats. The pump can be attached to the boats deck or to a board. Like with all the other pumps above, only one pumper at the time is needed. Photo courtesy of Antiques of the Sea.

A perfect team! #15 shallow water helmet and #15 shallow water pump. Photo courtesy of Bob Croot.

The E.J. Willis Co

Manufactured by the E.J. Willis Co of NEW YORK, NY, this pump was originally offered for sale with the Snead Shallow Water Cast Iron Helmet. The pump's main body and cylinder heads are cast iron. The cylinder's pistons, connecting rods, lever housing and lever handle are bronze. The lever itself is made of flat iron stock, and held in place by a brass cotter pin which is chained to the front of the pump. The handle is riveted to the lever. Each cylinder is held in place by four machine screws.

The name tag reads:




Specializing in Marine equipment

The tag also has a small banner or flag on each side of the name showing a 'W'. The tag is stamped brass and held in place by two machine screws. Snead later made their own pump for their Shallow Water Helmets which was a two stage two cylinder pump. Please scroll down the page to see the Snead Shallow Water Pump.



Photo courtesy of and thanks to Ed Fogderud


Who is able to contribute pictures of the TECO #600 (one cylinder) and TECO #805 (two cylinder) shallow water pumps? Please contact us

Let's have a look at two cylinder lever pumps with a somewhat higher capicity (remember our bore x stroke explanation?)


Korean KIM shallow water diving pump. Restored to look like a new one. No air-cleaning device, no depth-pressure gauge. The very basic design of this kind of pump. Photo courtesy of Bob Croot.

Lever pumps were only suitable for a maximum of 20 to 25 meters/75 feet of depth and demanded 2 to 4 people for operation. For longer dives, these guys had to be refreshed frequently so eight of them were needed. In greater depths two or more pumps were used parallel.

In normal operation these pumps would supply about 45 liters of air per minute at te surface. For a diver in 20 meters depth this would mean 45:3 (3 bar/atm of pressure at 20 meters instead of 1 at the surface) = 15 liters. However, to clear the helmet from carbon-dioxide at least 30 to 50 liters per minute are necessary ! Can you imagine how hard the pump operators had to work ? Rotary pumps had a much higher performance. Learn all about them in the next page.

Two stage lever pumps

In general, both cylinders supplied equal pressure. In some cases higher pressure was needed. For example to fill the high pressure reservoir when using regulator equipment. In those cases "two-stage pumps" were used. The compressed air was lead from the first cylinder to a second smaller cylinder where it would be compressed again.


2 stage lever pump made by Snead from New York.

Pump maintenance

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