Knowledge bank

How does a dosing pump work?

A dosing pump is indispensable for the precise addition of small quantities of liquids with high accuracy. Dosing pumps are used for pH adjustment or chemical injection. Lymas offers different materials such as PVC, PP, PVDF, and stainless steel. From basic on/off pumps to advanced variants that can be controlled via 4-20 mA signals or pulses from water meters.

Common types of metering pumps:

Diaphragm metering pumps are available in three different types and are always equipped with PTFE diaphragms: Magdos, which is a solenoid/magnet-driven pump, Memdos, which is an electric motor-driven pump with gearbox, Memdos smart, which has a stepper motor.
Piston dosing pumps are generally used for higher pressures (>10bar) and smaller flows, while diaphragm dosing pumps are used for slightly larger flows at lower pressures. The piston dosing pump is well suited if you need to push the liquid into, for example, a reactor under high pressure. The diaphragm pump is better suited to larger quantities for neutralisation in certain processes, such as water treatment. If you want to reduce pulsations, you can use a pulsation damper. This is to minimise stresses and pressure peaks on the piping systems. If you have a long pressure line, more than 10 metres, you must have a pulsation damper otherwise you can damage the pump.

If you want an almost completely pulse-free dosage, you should use a gear pump instead. It is more difficult to get an exact dosage with a gear pump, as piston or diaphragm pumps give an exact amount per stroke, while the gear pump can vary with temperature changes as the viscosity changes.

Motorised diaphragm metering pumps

  • ATEX approved for zones 1 and 2
  • Material: PVC, PP, PVDF or acid-proof steel
  • Capacity: Up to 8000 l/h
  • Control and monitoring via Modbus (Ethernet)
  • Stepper motor drive for adjustable pressure stroke speed

Motorised piston dosing pumps

  • Possibility to be supplied with multiple pump heads for precise mixing
  • Steam, water or electrically heated dispensing heads available
  • Material: Stainless steel and Hastelloy
  • Capacity: Up to 24 600 litres/h
  • Maximum pressure: Up to 400 bar

Pulse-free gear pumps

  • Available in shaft sealed or magnetic coupled versions
  • Capacity: Up to 13 cubic metres
  • Maximum pressure: Up to 25 bar
  • Material: PFA, stainless steel, titanium or Alloy-C
  • Helical gears for increased efficiency

How to choose the right dosing pump?

To choose the right dosing pump, you need to consider parameters such as type of media, temperature, flow and pressure. Follow these steps:

  1. Define which media and temperature the pump will work with.
  2. Determine the desired flow rate in litres per hour [l/h].
  3. Determine the back pressure in bar.
  4. Find the intersection point between the flow and pressure requirements to select the most suitable pump type.

We customise your pump in PVC, PP, PVDF or stainless steel

We offer dosing pumps with liquid-affected materials made of PVC, PP or PVDF and stainless steel. The diaphragms are made of PTFE as standard, and the pumps are customised based on the media to be pumped by the dosing pump. You can also choose between a number of different plastic qualities and also stainless steel, which means that we can optimise the choice of material according to the current application. The metering pumps are supplied with flange or thread connection.

Lyma Kemiteknik is an expert in reliable dosing pumps for harsh industrial environments

Lyma Kemiteknik delivers reliable and user-friendly dosing pumps to operations in the chemical industry, paper industry, steel/mining industry, energy and waste incineration. The operations have strict requirements for safety and operation.