Views: 111 Author: Site Editor Publish Time: 2022-10-11 Origin: Site
Diaphragm pumps, also known as control pumps, are the main type of actuators that operate with the aid of power to change fluid flow by accepting control signals from the modulation unit. Diaphragm pumps are generally composed of actuators and valves. The use of compressed air as a power source, for a variety of corrosive liquids, with particles of liquid, high viscosity, volatile, flammable, highly toxic liquids, can be pumped out and sucked up.
Pneumatic diaphragm pumps have four kinds of materials: plastic, aluminum, cast iron, stainless steel. Electric diaphragm pumps have four materials: plastic, aluminum, cast iron, stainless steel. Diaphragm pump according to the different liquid media are used rubber, neoprene, fluorine rubber, polyvinylidene fluoride, polytetrahexaethylene. To meet the needs. Placed in a variety of special occasions, used to pump the kind of conventional pumps can not pump the media.
Diaphragm pump according to its power with the actuator used, can be divided into pneumatic, electric, liquid three, namely, compressed air as the power source of pneumatic diaphragm pump, electric diaphragm pump with electricity as the power source, liquid medium (such as oil, etc.) pressure as the power of electro-hydraulic diaphragm pump, in addition, according to its function and characteristics, there are solenoid valve, electronic, intelligent, field bus type diaphragm pump, etc.. Diaphragm pumps have many types of products and a wide variety of structures, and are still being updated and changed. Generally speaking the valves are universal and can be matched to pneumatic actuators as well as to electric or other actuators.
The role of diaphragm pumps in process control is to accept control signals from regulators or computers, to change the flow of the regulated medium, to maintain the regulated parameters within the required range and thus to automate the production process. If the automatic adjustment system is compared with the manual adjustment process, the detection unit is the human eye, the adjustment and control unit is the human brain, then the execution unit - diaphragm pump is the human hand and foot. To achieve a certain parameter of the process such as temperature, pressure, flow, level and other regulatory control, are inseparable from the diaphragm pump. Therefore, the correct choice of diaphragm pump in the process automation is of great importance.
Diaphragm pump, also known as the control pump, is the main type of actuator, by accepting the control signal output from the regulatory control unit, with the help of power operation to change the fluid flow. Diaphragm pumps are generally composed of actuators and valves. If the actuator used by its power, diaphragm pumps can be divided into pneumatic, electric, liquid three, namely, compressed air as the power source of pneumatic diaphragm pumps, electric diaphragm pumps with electricity as the power source, liquid media (such as oil, etc.) pressure as the power of electro-hydraulic diaphragm pumps, in addition, according to its function and characteristics, there are solenoid valve, electronic, intelligent, field bus type diaphragm pumps, etc.. Diaphragm pumps have many types of products and a wide variety of structures, and are still being updated and changed. Generally speaking the valve is universal and can be matched with either a pneumatic actuator or an electric actuator or other actuators.
4.1 diaphragm pump valve body type selection valve body selection is the zui important link in the selection of diaphragm pumps. Diaphragm pump valve body types are many, commonly used are straight single-seat, straight double-seat, angle, diaphragm, small flow, three-way, eccentric rotation, butterfly, sleeve type, spherical and other 10 kinds. Before selecting a valve, the medium, process conditions and parameters of the control process should be carefully analysed, sufficient data collected to understand the requirements of the system for diaphragm pumps, and the type of valve to be used should be determined according to the data collected. In the specific selection, the following aspects can be considered:
(1) The spool shape structure is mainly considered based on factors such as the flow characteristics and unbalance forces selected.
(2) Wear resistance When the fluid medium is a suspension containing a high concentration of abrasive particles, the spool, seat joint surface will be subject to severe friction every time it is closed. Therefore the flow path of the valve should be smooth and the internal material of the valve should be hard.
(3) corrosion resistance due to the corrosive nature of the medium, in the event that the adjustment function can be met, try to choose a simple structure valve.
(4) medium temperature, pressure when the medium temperature, pressure and high change, should be selected spool and seat material by the temperature, pressure change small valve.
(5) prevent flashing and cavitation flashing and cavitation only in liquid media. In the actual production process, flash and cavitation not only affect the calculation of the flow coefficient, but also the formation of vibration and noise, so that the service life of the valve becomes shorter, so in the selection of valves should prevent the valve from flash and cavitation.