A membrane pump is a pump of a volumetric type, with a diaphragm (or a membrane) used as a main operating element. The membrane may be driven pneumatically, mechanically or hydraulically; it serves also as a displacer.
Air is fed to the membrane, compressing it and moving the operating liquid towards the outlet. At the same time, the opposite membrane creates vacuum, resulting in liquid suction. Then, these operations are carried out in opposite direction.
Membrane pumps are capable to implement self-suction; therefore, they are commonly installed on the reservoir to be evacuated (or over it). These units can work with substances containing solid particles or highly viscous substances.
These pumping plants can work dry, not resulting in any damage for the main operating element; also, these pumping plants are easy for maintenance. Membrane pumps proven their excellent efficiency for pumping the media for which other centrifugal pumps are inapplicable (when the medium damage risk exists).
The membrane pumps are easy in terms of their design and commissioning procedures. Membranes move horizontally on the shaft; they are driven by the compressed air flowing to the air valve. Membranes also serve as seals between the unit’s liquid chambers and air chambers. The operating liquid enters the pumping plant through the suction pipe, driven by the vacuum generated in liquid chambers due to the membranes firmly pressed against the casing. Then, the set of ball valves is used by membranes to move the pumped liquid towards the discharge pipe. The set of ball valves in the pumping plant is capable to pass the substances with inclusions (the size of inclusions is ≤30 mm).
Membrane pumps with metering devices also exist. In these units, forced membrane movements are used to implement the pumping process; the membrane serves also as the chamber wall. Pneumatic, electromagnetic or electromechanical drives can be used to implement the membrane swinging movements in these pumps.
The most common metering pumps are solenoid pumps. In these pumps, the membrane is moved by the rod driven by the electromagnetic field created by the solenoid.
The metering process is implemented by the rod movement frequency and amplitude variation. In this design, one operating cycle includes the discharge and suction processes; their length is equal. The drive power in these pumps is not very high; therefore, they are used when there is no need for high capacity (the ultimate value is 60 litres/hour) or high head (the ultimate value is 30 bar).
Usually, the metering device in these units is made of plastic, the valves are made of ceramics or special steel, the metering head casing is made of PMMA or polypropylene, and the membrane is made of fluoroplastic. Membranes made of composites are also used; they are even more reliable and durable. The materials for key components are selected in accordance with media to be processed by the pump.
Solenoid membrane pumps can be controlled remotely. A pulse signal or a current signal (from 0.4 to 20 mA) can be used as a control signal.
Membrane pumps are simple in terms of their design: there are no rotary parts, no gearbox, no motor and no gland seals. The design free of end seals is especially important for food industry, because it is very important to prevent contamination of products by lubricants in this industry. Due to these parameters, the pumping plant is more wear-resistant and leak-safe. Also, diaphragm pumping plants have small size and weight, and they are applicable for wide range of media (water, viscous substances or substances containing the pieces as large as 10 mm). The units require minimum service (no lubrication is required for mechanisms), easy for maintenance, cost-effective, have low costs (membrane pumps are 30-40% cheaper than cam-driven or screw pumps) and environmentally-safe.
Due to their advantages, membrane pumps are widely used in several industries involving aggressive or highly-viscous media (such as chemical industry, printing, paper industry, paint and varnish industry). Also, these pumps are actively used in water treatment systems (for metering and pumping the reagents), water supply systems, agriculture, beverage industry.
We are convinced that our company ENCE GmbH will become your reliable and efficient distributor (authorized representative) of your membrane pumps in the Russian market.
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