What is a self-priming pump

Some of the misconceptions about the self-priming pump are as follows:

1. Self-priming pumps need to be re-primed with water after a pumping cycle. This is not the case with “guaranteed re-primers”, like Gorman-Rupp’s Super T, Super U, and Ultra V. These pumps only need to be charged with liquid once, and they retain enough liquid in their casings to guarantee re-priming each and every time they are called upon to pump.

2. Self-priming pumps are inefficient. In most cases, the hydraulic efficiency of a self-priming pump will not be as high as that of a standard centrifugal pump or submersible pump. If engineers looked no further than this, self-priming pumps would never be used, and asset owners would pay a lot more for infrastructure costs and/or the maintenance of these pumps for the life of the asset. But as many engineers and asset owners have found, the cost savings in infrastructure and maintenance can far outweigh the savings one may achieve in selecting a slightly more hydraulically efficient pump.

3. Self-priming pumps are too expensive. It is true that self-priming pumps are more expensive than standard centrifugal pumps. This is because there is a lot more material [because of the need for an outer casing], more components and more machining. This should be weighed up against the capital cost savings [no dry well], the ease of access and the ease of maintenance offered by a self-priming pump. Also, some self-priming pumps are more expensive than others. Again the facts need to be weighed up. A pump purchased that has been engineered and produced by a company that has been manufacturing pumps for over 80 years [like Gorman-Rupp] can be considered as an investment in reliability. Pumps manufactured by companies attempting to copy market leaders will invariably not be able to meet efficiency, quality, repeatability and reliability standards of the market leaders, and purchasers can rightly consider these as costs.