Diaphragm Metering Pumps
Diaphragm metering pumps are a type of pump that pumps liquid (such as water,
chemicals, gas, etc) in a particular motion and therefore flow. The rate of flow can be changed at any time and as
the name suggests, diaphragm metering pumps work by compression and decompression; so the liquid can only pass
through the pump during specified motions. In this type of pump, the natural flow of fluid is maintained and the
fluid will not go back in the opposite direction.
Diaphragm Metering Pumps - Where Are They Commonly
Found
These pumps are designed to be used in the following areas:
• Water treatment plants
• Chemical processing plants - the handling of corrosive fluids
• Swimming pools
• Farming and agricultural industry - the handling of slurry
• Food processing and manufacture
• Brewing and distilleries
The main benefit of working with diaphragm metering pumps is that there is very low
possibility of product leakage and in the case of poisonous or hazardous liquids or chemicals, this is
imperative.
How do diaphragm metering pumps work? Diaphragm metering pumps can be operated on fluid power (hydraulics) or mechanically. The diaphragm itself is
made of a durable and heavy duty material which also prevents liquid from seeping through the seal. Some
diaphragm metering pumps come with an auto-detection failure system which proves to be very beneficial in
keeping the metered fluid contaminant-free.
Types Of Hydraulic Operated Diaphragm Metering Pumps
There are three main types of hydraulic operated diaphragm metering pumps:
• Single
• Double
• Sandwich
Single diaphragm metering pumps has a partition so that the hydraulic chamber is carefully
sealed away from the fluid that is being discharged.
Double diaphragm metering pumps has two diaphragms just as you might expect from its name. If a
highly corrosive fluid damages one diaphragm, the backup diaphragm will take over the job of the damaged one
which provides enough time to replace the worn out diaphragm. This ensures that the dangerous liquid does not
leak out. This type of pump is generally made to handle double the flow than that of the single. The way in
which they are designed means that there is no contact whatsoever between the power source and fluid being
pumped.
Finally, sandwich diaphragm metering pumps are essentially two of the same pumps fitted
together to work as one. The beauty of this type of metering pumps is that should one of them fail unexpectedly,
the other one can act as a backup and they are monitored internally by a pressure gauge. Next we will take a
look at electronic metering pumps.

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