How does a dosing pump work ?

Dosatron is the original inventor of the non-electric proportional dosing pump since 1974.
Dosatron technology is a passive volumetric dosing pump based on a water driven hydraulic motor piston pump activated only by pressure and flow of water without any electricity or any measuring device.
Such a pump is composed of two main elements: a passive water driven hydraulic piston and a dosing piston.

How does the hydraulic piston work?

The motor piston moves under the pressure of water. A system of valves allows the movement to be reversed. This water powered piston creates a reciprocating motion along the axis of the pump body.
Each piston cycle corresponds to a predetermined volume of water, which passes through the pump. The speed of the motor varies proportionally to the water flow.


How does the dosing piston work?

The dosing piston, driven by the hydraulic piston, mechanically displaces the volumes of fluid trapped in the system. On the suction side, the volume expands, while on the discharge side, it contracts. The volume per stroke is therefore fixed and theoretically constant, regardless of outlet pressure, inlet vacuum or fluid properties.


how does a dosing pump work

                 How does a dosing pump work ?

How is the injection rate controlled?

A non-return suction valve opens during the suction in the additive pipe and it closes during the injection and mixing phase.
The dosing seal this vacuum by sealing the dosing body and the dosing piston. The dosing seal serves as a pressure valve (when lowering).
The metering piston therefore injects a fixed volume of additive at each cycle and acts as a reciprocating piston.
The dosing piston will inject the defined volume of additive in proportion to the volume of water passing through the water-powered piston. This volume of additive is manually adjustable by adjusting the capacity of the dosing body.
The principle of operation thus ensures a constant and continuous dosage proportional to the water flow, independent of variations in water flow and pressure.


How is the additive mixed?

The injection of the additive into each volume of driving water in the mixing chamber allows a continuous and homogeneous downstream of the dosing pump.
The dosing piston therefore continuously injects a fixed volume of additive and acts as a reciprocating positive displacement piston.
The dosing piston will inject the set volume of additive in proportion to the volume of water passing through the water driven piston. This volume of additive is manually adjustable by adjusting the capacity of the dosing body.
Therefore, the operating principle ensures constant dosing, independently of the variations in flow rate and pressure of the water. The injection of the additive is proportional to the water flow rate.


Adjustable dosing without measuring device

The maximum dosing ratio is given by theoretical calculated ratio: surface of dosing piston divided by surface of water piston.
The mechanical adjustment system allows the user to reduce manually the dosing volume to obtain a lower dosage. This is obtained by adjusting the stroke length of the dosing piston.
As during the operation, there is no measuring device to control or interact with the dosing assembly.
The dosing percentage is therefore only obtained by theoretical construction, which is only based on hydraulic behaviors described above.
The dosatron technology is available in a wide range of dosing.

Dosing pump working animation

Summary

Dosatron has been a dosing pump manufacturer for almost 50 years.
The Dosatron is a passive non-electric volumetric proportional dosing pump without measuring device composed of two volumetric reciprocating pistons, the first one acting as hydraulic volumetric piston to create a linear movement, the second acting as volumetric and proportioning positive displacement reciprocating dosing pump.

Advantages of the Dosatron pump

  • Non-electric
    Unlike electric pumps, the Dosatron metering pump is activated only by pressure and flow of water.
  • Dosing accuracy
    The high precision of the constant dosing of the hydro-motor pumps eliminates any risk of overdosing, saving the concentrated additive and contributing to the respect of the environment.
  • Proportional dosing and homogeneous solution
    It has been designed to inject the precise dose of concentrated additive that is continuous, homogeneous and directly proportional to the volume of water entering the dosing pump, regardless of the variations in flow and pressure that may occur in the water system.
  • Low operating costs
    Life cycle costs are very low due to its electric-free, servo-free design and easy maintenance.

The proportional dosing unit integrates 4 functions realized by mechanical construction.

  • Measuring: hydraulic volumetric motor for water flow,
  • Dosing: continuous proportional injection of liquid or soluble concentrate,
  • Regulating: proportionality controlled by the water flow,
  • Mixing: homogenisation integrated in the pump body.
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