Posted on Mar 6, 2020
For liquid water transmission, pumps and valves are important units for workers in the working field. However, pumps are not like valves in many phases. Normally pumps are equipment that moves fluids-state substance such as liquids by its mechanical action. Traditionally speaking, pumps can be categorized into three major kinds based on the method those pumps exploited to move the targeted substance.
As mentioned above, the three categories are based on the methods that pumps used to transmit the targeted substance. These three types are determined by the way they move the fluids, and there are direct lift, displacement, and gravity methods that people invented in the early stage of industrial development. That is to say, there are three kinds of pumps, one is direct lift pump, and the other is displacement pump, and the last one is the gravity pump. Pumps are typically operated by either typically reciprocating or rotary mechanism, and these all consume energy to perform mechanical work moving the targeted fluid. On the one side, mechanical pumps can also be submerged in the fluid in which they are pumping, or they can also be placed external to the fluid. The mechanism may be slightly different but the idea of liquid transition shall be the concern.
Moreover, pumps can be categorized by their method of displacement into positive displacement pumps, impulse pumps, velocity pumps, gravity pumps, steam pumps and valve-less pumps. These further categorization help users to decide whether they shall choose what types of pump to deal with their utilization cases. Besides, there are two basic types of pumps, that is, positive displacement and centrifugal pumps. Generally speaking, pumps can operate through many power (energy) sources, such as manpower’s’ manual operation, electricity, engines, or even wind power. Those energy sources can be a wide variety of equipment which comes in any sizes, from microscopic for use in medical applications to large industrial pumps for waterworks, or ordinary size industrial pump for machine tool coolant transmission. Industrial pumps serve in a wide range of applications such as pumping water from conventional wells, aquarium filtering duty, pond filtering tasks, in the car industry for water-cooling and fuel injection, in the energy industry for pumping oil and natural gas or for operating cooling towers.
In the machine tool sectors, pumps are used to move cutting liquids, coolants, etc. in the medical industry, pumps are used for biochemical processes in developing and manufacturing medicine, and as artificial replacements for body parts, in particular the artificial heart and penile prosthesis. Let’s move on to the next subject. As a result, unlike centrifugal pumps, a positive displacement pump can produce the same flow at a given speed no matter what the discharge pressure. As a result, positive displacement pumps are constant flow machines. At the same time, however, a slight increase in internal leakage as the pressure increases prevents a truly constant flow rate. That is to say, a positive displacement pump must not operate against a closed valve on the discharge side of the pump, as it has no shutoff head like centrifugal pumps. Therefore, positive displacement pumps operating against a closed discharge valve continue to produce flow and the pressure in the discharge line increases until the line bursts, the pump is severely damaged and impacted.