Drafting Tip #06 - Use Dual Suctions to Increase Pump Capacity
By President Mark Davis
July 31, 2014
A very good way to increase the pump capacity of pumper (one that is rated 1500 gpm or less) is to draft using two suction inlets. Pumpers that have midship mounted pumps rated 1,500 gpm or less are usually rated using only one of their side suction inlets. By using both suction inlets, capacity can be significantly increased as long as the motor can produce sufficient torque to drive the pump. For example, a Hale Q-Max 1,500 gpm pump powered by a 500 hp motor can flow in excess of 2,200 gpm from draft using dual suctions. Once again, this reinforces the value of carrying additional suction hose and strainers on a pumper that serve rural communities.
This 1,500 gpm pumper used dual, 6-inch suctions to improve its flow capacity during a recent water supply drill in Peace River, Alberta.
The Peace River pumper used Storz style fittings on its suction hose. Note the "grey" suction gasket - which is important when drafting.
The pumper did not carry enough suction hose to start with two suction intake lines, but because it was equipped with a suction inlet control valve - the second line could be set up without shutting down the operation.
With only one pumper committed to drafting - it is very important to make the most of that pump's capability.
A suction inlet control valve is a critical tool in the rural water supply field. You do have to be careful about the size of the internal waterway so that flow is not restricted.
The driver also used a section of 3" suction hose connected to the auxiliary suction inlet on the driver side - thus, three suction lines.
