A high pressure Self-priming pump is a useful pump for any applications where high volume pumping is required. Self-priming pumps are used in many different applications in which normal centrifugal pump applications are either insufficient or unsuitable. Applications from water to fuels, grey water or sewage, right up to raw sewage, chemical sludge and industrial waste can all be effectively serviced by self-priming centrifugal pumps. These pumps can also be used to serve other important purposes such as for emergency flushing, sewage treatment plants, desalination plants and industrial treatment plants.
The basic design of a self-priming pump consists of a rotor, block or housing, and a connecting rod. The rotor is placed above the housing and is spinning at a low-speed. As the rotor turns, it forces a gas such as a mixture of fuel, air or oil to be forced down into the housing. This forces the liquid mixture into a lower region of the pump’s cavity, hence reducing the pressure. The lower pressure reduces the pressure in the remaining part of the tank.
In a typical case, the housing is made out of either plastic or metal. Plastic housing is more suitable than metal as it is lighter and allows the pump to be more robust. Metal housing tends to be more expensive than plastic and may not necessarily be more efficient. It is therefore common for both the housing and the pump to be made out of the same material.
The most popular type of Self-priming pump is the Gorman-Rupp system. This type of Self-priming pump has a seating block that is installed on top of a rotary drum or cylinder assembly. As the rotor is spun around, the block pushes a plunger that opens the priming tube, forcing a stream of gas into the priming medium. The design of the Gorman-Rupp Self priming pump makes it possible to control the amount of gas produced by the pump, thus controlling the pressure.
Self priming pumps usually come in two basic types – open-ended and enclosed casing. The Closed casing Self priming pump is installed with its casing outside the pump housing. This means that the casing acts as a sort of “sewer screen” and ensures that no liquid or gas escapes from the pump. This type of Self-priming pump is commonly used for household applications. For industrial or commercial applications, the open-ended Self priming pump is preferred.
Self priming pumps also differ from centrifugal pump in that centrifugal pump primers are mounted inside the rotating drum or cylinder, whereas self-priming pumps are mounted outside the housing. When the rotor is spun around, the primer pushes on the plunger that opens the priming chamber. Self priming pumps have a clutch system that ensures that the primer does not open while the rotor is spun around. This prevents the primer from closing again once the rotor has spun off. A final advantage of Self-priming pumps is that they do not need oil for lubrication.
There are several disadvantages of Self priming pumps too. In order to operate properly, Self priming pump requires a sufficient source of water. This water could be a fresh water supply or an external source such as a river or a pond. It is also necessary to keep the Self priming pump in a circulating area. This facilitates the smooth flow of air and gas through the pump and ensures that the prime is maintained at all times.
Self-priming pumps usually have two main parts; the priming chamber and the suction line. The priming chamber is the part that is in direct contact with the liquid; hence the name. The suction line is an external suction line that is attached to the pump and carries the liquid through the pump to the suction line. Self priming pumps operate in the same fashion as standard centrifugal pump where a roller passes through the fluid and the area where the head stops is the priming area. This ensures that the same pressure is maintained across the two sections of the chamber.
