A chain pump is a type of water pump that was used for centuries but has fallen out of favor in the modern age. The pump consists of a pipe connected to a water supply, a circular chain and flat platters that are the same size and shape as the pipe. These platters are connected to the chain, which is then drawn up through the pipe. Water is caught on the platter and brought up to the surface. The chain is circular, so as the platters rise on one side of the chain, they drop back into the water on the other.
Use of the chain pump was first recorded in ancient Egypt and Babylon. These early pumps were nearly identical to the ones used thousands of years later. The original chain pumps would use animal or human power to turn the chain, often through a secondary system such as a push wheel. As the wheel turned, it would activate an associated crank, which would cause the chain to move. These early wheel systems rarely provided any mechanical advantage, but they did make the process easier on the workers.
The first major innovation in the system came around the beginning of the second millennium when Islamic scholars added a flywheel to the system. This addition both smoothed out the chain’s movement and provided a small mechanical advantage to the system. A mechanical advantage allows a system to output more power than it takes in, meaning less work went in to bringing up the same amount of water.
Hundreds of years later, the pump was motorized. This style of chain pump was very uncommon, as other pump styles had taken its place. It was most common in places with little infrastructure or inside the bilge in ships. In both cases, its popularity was due to the relative simplicity of the system combined with its low power consumption.
While most chain pumps used the pipe and platter method, there were a handful of variations. The most common alteration was the bucket system. The chains in these pumps contained buckets instead of the standard platters. The water would come up and a worker would manually empty the bucket. This chain pump style typically didn’t have a pipe at all, just an open well.
In China, a wide square pallet was used as a platter. These systems would bring up enormous amounts of water, which would generally flow into irrigation ditches. The Chinese also used a modified chain pump to fill cisterns high up on cliff sides. These pumps operated similarly to a bucket pump, but would generally pull from an active water source such as a lake or river rather than an underground source.