Positive Displacement Pumps are utilized to transfer fluids that have high viscosity like fuels, food ingredients or chemical. These pumps are commonly employed for applications that require precise measurement.

The piston, diaphragm, or helical-rotor, is pushed back and forth in a cycle. This cycle permits them to move a fixed volume for each shaft turn.

Positive displacement pumps that have an rotary sprayer

Positive displacement pumps draw an amount of liquid into it and pushes it out via an outlet valve. These pumps are utilized to transport liquids that range in viscosity from those thicker than water, to sludges and Emulsions. They can be operated at high pressures and are ideal for use in applications requiring precise dosage. These pumps are preferred when working with fluids that contain solid particles or abrasives. There are various types of positive displacement rotary pumps, including piston pumps, gear rotary and screw pumps.

Since these pumps don’t have impellers, they’re not as susceptible to the problems that can affect centrifugal pumps, such as cavitation and wear. Abrasive feeds can result in excessive wear to the components of certain positive displacement tu dieu khien may bom. This is especially true for rotary pumps that utilize pistons or plungers to trap and displacing fluid. Avoiding feeds with abrasive particles when it is possible.

Another issue with Rotary positive displacement pumps is that they could generate pulsed discharge. This could cause vibration and noise in the system and cavitation which can cause damage to pipes. This can be minimized through the use of multiple pump cylinders and pulsation-dampers.

Another advantage of a rotary positive displacement pump is that it will often self-prime. This is due to the tiny clearances within the pump. However, care should be taken to make sure the pump isn’t running empty for long periods of time as this can reduce the efficiency and life span of the seal.

Pumps that Reciprocate Positive Displacement

They draw and pressurize liquid using pistons in the piston. When the piston is moved between its sides, it entraps liquid between the outlet and inlet valves, which creates the possibility of a differential pressure which overcomes the valve at the inlet to allow fluid to leave. Contrary to centrifugal pumps, which are sensitive to viscosity changes and positive displacement pumps keep their flow rate independently of the pressure in the system.

These pumps are ideal for use in applications that require accurate measurement or transfer of material such as abrasive and dangerous substances. In addition, they’re self-priming, which reduces downtime and cost of labor by eliminating the need for manual re-priming.

But, one drawback to the pumps is that they may keep building pressure inside the pipework that delivers them until an event releases the pressure. It may be the pump or the liner. This can lead to a lot of noise and vibration in operation. To mitigate the effects of this, they typically require additional components such as pulsation dampeners in the discharge line and in the pipework for safety and security. Moreover, the internal design of these pumps tends to cause them to be more costly and difficult to maintain than centrifugal pumps. They are able to handle potentially hazardous or corrosive fluids as well as their ability to perform consistently even at low pressures overcomes these issues. These pumps are ideal for use in high-viscosity applications in the drilling industry, chemical processing, and pharmaceutical industries.

Gear Pumps

Gears, unlike diaphragm pumps they do not shed the fluid. They are great for moving shear sensitive liquids, such as emulsions, microbiological cultures, and food products. Gear Pumps are also good to transfer liquids that are prone to changes in viscosity.

They are compact and cost efficient. They can be constructed from stainless steel or other materials. They offer high efficiency levels of up to 85% or more. They are reversible meaning they operate in both directions to make sure that the entire contents of a hose are completely emptied. Self priming, they do not require external air. They are typically Atex rated (explosion resistant) and can handle solvents.

The shafts are housed within sleeves which are connected using a recirculating polymer to provide the lubrication. The recirculating polymer is created by the difference in pressure between the two gears. They are only able to run dry for a limited time and should be kept properly lubricated to avoid galling. This can happen when the melt of the polymer is too hard or the shear temperature is too high.

The gears rotate in opposite directions, picking the polymer before transferring it to exit around the outside of the meshed cogs. Gears are kept lubricated by using grooves for lubrication. They are double or single jacketed and fitted with different seal types – including sealing, mechanical, gland packing/stuffing, or magnetic coupling when there is no seal.

Diaphragm pumps

The most adaptable pump in the world Diaphragm Pump can be easily transported to wherever it’s needed – just connect your air and liquid lines and you’re all set to go. No matter if your task requires low viscosity spraying, massive solid handling, or chemical and physical force, these pumps can handle it.

Diaphragm Pumps contain two chambers of compressed air which contract and expand in alternating volume. This causes the effect of pumping. A hermetic seal between the diaphragm, the drive mechanism, and the chamber of compression permits the pump to transfer to, compress and expel the medium without needing the use of lubricants.

When suction is applied the air pressure is applied to the left diaphragm to transform it from a flat to a convex shape that opens the check valve for inlet and pulls fluid into the pump. Then, the pump shaft shifts to the right while the right diaphragm shifts from a concave shape to an convex form and shuts the outlet check valve, while fluid is released from the discharge valve.

A regulator in the input regulates the air pressure. The pumps will stop if the air pressure is higher than the discharge pressure. This prevents the pump from harming the system pipework or itself. This type of high-pressure, air driven pump can reach the maximum pressure of 30 psi however the actual pressure is lower as the diaphragm will break above the pressure.