Flowrates can be varied a number of ways.

• The Grosvenor Variflow Plunger Pump has a “Lost Stroke Unit” fitted between the Gearbox and the Pump Body. This allows, through a hand operated Micro Adjuster Knob, for the length of stroke to be altered between 0% and 100% of the full stroke capacity of the pump. Pump flowrate is adjustable and constant over a period  but the continuity of flow is compromised.

• To ensure a smoother more constant flow of liquid requires constant speed input into the gearbox. This can be effected with the use of a Variable Speed Unit fitted between the motor and gearbox. Such a unit would be fitted to one of our standard fixed rate pumps and  is generally adjusted by a handwheel and depending on the type of  unit used will give an input speed and thus pump output range down to 0%.

• For an electronic solution, we now offer the Varitronic Control Unit . A versatile & capable IP66 washdown inverter drive integrated within the pump unit, providing a compact control solution with manual flow control at the pump or remotely via process control I/O. A scalable display allows the drive to be calibrated, within process, to show actual flow rate.  A broad selection of analogue/digital I/O & relay outputs provides the user with a number of process control capabilities. In addition, an on-board PID controller can be utilised for simple, stand alone flow control applications.

Driven by an electric or compressed air motor through a worm and wormwheel reduction gear, an eccentric device makes a connecting rod travel backwards and forwards and pushes and pulls a crosshead through the gearbox casing.

Connected to the crosshead is a Plunger that enters the Pump Body through a set of Gland Packings.

With the Pump Body full of liquid, the Plunger will be pushed into the Pump Body Chamber and displace the same amount of liquid as the volume of the Plunger movement. As the Inlet/Suction Valve Assembly is being held closed by the pressure within the Pump Body, this liquid will be forced out of the Outlet/Discharge Valve Assembly.

As the Plunger is pulled back out from the Pump Body the Outlet Valve will be forced closed and the liquid pulled through the Inlet Valve by vacuum, into the Pump Body Chamber ready for the next forward stroke of the gearbox.

Displacement of fluid is directly proportional to the volumetric movement of the Plunger. This makes a Plunger Pump very accurate and produces a known flow volume for each stroke of the Plunger. However, the speed of the motor will be affectd by voltage fluctuations and a flowrate should be determined over a period of time.

A Plunger Pump will operate and perform consistently with a constant motor speed and efficient valves and Gland Packings. If Valves or Gland Packings are not sealing correctly then performance will suffer.

A Plunger Pump will give constant Flowrate at the designed High Pressure if all components are in good working order.

For Variable Flow Plunger Pumps please refer to the Category of the same name.

For new customers we will issue a Proforma Invoice for the first order. If you wish you may then apply for a Credit Account, subject to references,  for future orders.

Payment may be made by BACS transfer, Credit Card, Cheque or Cash.

For High Value Special Pumps or Chemical Dosing Systems that require a large capital outlay for special purchases, we hold the right to ask for an initial deposit.

Because of the range of sizes and variations for each model of pumps, each manual covers the complete range of sizes, although most of the content applies to and is common to every pump.

Parts Lists and Maintenance/Overhaul notes may include references and numbers that are different to your own pump. It is therefore important to note that any request for Information or Spare Parts for your pump must include the Serial Number that is stamped on a plate at the gearbox end of the pump.

Manuals can be adapted to cover your own actual pump but may be charged for.

Our standard pumps are normally assembled from stock components for a quick delivery but any special requirements such as non standard materials or special electric motors will extend that time.

Our smaller Pygme Plunger and Pygme Diaphragm Pumps can normally be dispatched within 3-7 days depending on the production schedules at the time.

The S-Type Plunger and S-Type Diaphragm pumps and the M-Type Double Acting piston pumps are again generally dispatched within 3-7 days.

Our larger range of I-Type and L-Type Double Acting Piston pumps are made to order as specials and the lead times for these models are longer as components have to be manufactured. The lead time for these Double Acting pumps is typically 6-8 weeks.

To select the correct dosing pump it is important to know some basic information.

• Flowrate (Fixed or Variable).
• Output pressure required.
• Chemical to be pumped.
• Viscosity and Specific Gravity of the fluid.
• Suction type (is the chemical dosing pump fed from below or gravity fed from above.
• Electrical supply available.
• Environmental conditions.

Once the above is known, a suitable chemical dosing pump can be selected to suit your needs.

If you are unsure then contact us  and we will be pleased to assist.