Our range of mechanical diaphragm pumps are designed for process applications where the precise metering of chemical is required. The pump series all work using volumetric cavity displacement to ensure that the chemical is metered accurately into the process with a linear relationship between the stroke length and the amount of chemical dosed into the process.
The range differs from our piston dosing pump range in the method of delivery. In the piston dosing pump the piston is directly in contact with the liquid, whereas in the pump a diaphragm is attached to the piston. This results in only the PTFE face of the diaphragm and the pump head itself being in contact with the chemical, which is dosed as the reciprocating movement of the diaphragm causes a volumetric displacement inside the head of the pump.
The PTFE diaphragm is very chemically resistant and when paired with the appropriate head material for your application, should ensure compatibility with a wide range of chemical reagents including concentrated chemicals.
Mechanical Diaphragm Pump – Head Materials
To ensure compatibility with a wide range of chemicals we offer a number of different head materials which include:-
316 Stainless Steel
PolyPropylene
PVC
PVDF.
Mechanical Diaphragm Pump – Stroke Length
The PTFE diaphragm is attached to a piston which is in turn driven by the motor and gearbox assembly. Each movement of the PTFE diaphragm is driven by the piston, ensuring the amount of fluid displaced is both linear and repeatable, allowing us to accurately dose the required amount of chemical into an application.
As the length of stroke increases, the amount of fluid transferred during the positive cavity displacement increases.
Each the motor driven diaphragm pumps has a micrometer stroke adjustment dial which means that the strong-stroke length can be adjusted across a range of 0 – 100%. By reducing the stroke length, the amount of chemical delivered by the mechanical diaphragm pump can also be reduced. The relationship between the stroke length and volume delivered is linear, allowing us to continue to dose in an accurate and repeatable manner.
To ensure the chemical dosing is accurate and repeatable, we recommend that the stroke length isn’t adjusted below 20% of the rated stroke length.
In some applications where viscous solutions are dosed or where chemicals have a low vapour pressure, using a lower or higher number of strokes per minute respectively, can offer significant advantages. If you’re unsure as to the right gearbox ratio to use for your application, please don’t hesitate to contact us.