Introduction of Domestic Pumps
A Domestic pump is a device that moves fluids (liquids or gases), or sometimes slurries, by mechanical action. Domestic pumps can be classified into three major groups according to the method they use to move the fluid: direct lift, displacement, and gravity pumps.Domestic pumps operate by some mechanism (typically reciprocating or rotary), and consume energy to perform mechanical work by moving the fluid.
Efficiency of Domestic Pumps
Domestic Pump efficiency is defined as the ratio of the power imparted on the fluid by the Domestic Pump in relation to the power supplied to drive the Domestic Pump. Its value is not fixed for a given Domestic Pump, efficiency is a function of the discharge and therefore also operating head. For centrifugal Domestic Pumps, the efficiency tends to increase with flow rate up to a point midway through the operating range (peak efficiency) and then declines as flow rates rise further. Domestic Pump performance data such as this is usually supplied by the manufacturer before Domestic Pump selection. Domestic Pump efficiencies tend to decline over time due to wear(e.g. increasing clearances as impellers reduce in size).
When a system design includes a centrifugal Domestic Pump, an important issue it its design is matching the head loss-flow characteristic with the Domestic Pump so that it operates at or close to the point of its maximum efficiency.
Working Principle of Domestic Pumps:-
All Domestic Pumps use basic forces of nature to move a liquid. As the moving Domestic Pump part (impeller, vane, piston diaphragm, etc.) begins to move, air is pushed out of the way. The movement of air creates a partial vacuum (low pressure) which can be filled up by more air, or in the case of water Domestic Pumps, water. This is similar to sucking on a straw. A partial vacuum is created in your mouth when you suck on the straw. The liquid is pushed up the straw because of the pressure differences between your mouth and the atmosphere.
The Domestic Pumping action is your mouth closing around the liquid (in your mouth) and forcing it down your throat.
The Pumping process of Water
The Domestic Pumping of water is a basic and practical technique, far more practical than scooping it up with one's hands or lifting it in a hand-held bucket. This is true whether the water is drawn from a fresh source, moved to a needed location,purified, or used for irrigation, washing, or sewage treatment, or for evacuating water from an undesirable location. Regardless of the outcome, the energy required to Domestic Pump water is an extremely demanding component of water consumption. All other processes depend or benefit either from water descending from a higher elevation or some pressurized plumbing system.
The ancient concept of the aqueduct took simple and eloquent advantage of maintaining elevation of water for as long and far a distance as possible. Thus, as water moves over great distances, it retains a larger component of its kinetic energy by spending small portions of this energy flowing down a slight gradation. Granted, a useful aqueduct system ultimately depends on a fresh water source existing at a higher elevation than the location where the water can be of use. Gravity does all the work. In all other instances, Domestic Pumps are necessary.
Vane and Impeller Functions in Domestic Pumps
The radial vanes within a water casing cause the water to spin when the casing rotates or when the vanes themselves are rotated, making them crucial components in most centrifugal Domestic Pumping systems. Likewise, the impeller is an integral Domestic Pumping unit because it provides the rotational force that moves the vanes. Common types of vane and impeller designs include: