The definition and application of the dosing metering pump

Dosing metering pump is a machine that can measure the liquid to be transported. It is often used in various types of medicines to add complete sets of equipment, so it is also called dosing pump. Usually described as: Dosing metering pump is a special volume pump that can meet various strict process requirements, flow can be steplessly adjusted in the range of 0-100%, used to transport liquids (especially corrosive liquids) .

1. What important things should you pay attention to when running the dosing system?
Dot pressure, stroke frequency, suction height, altitude, chemical corrosiveness.

2. When the outlet of the metering pump is at atmospheric pressure, is there any way to improve the repeating measurement accuracy of the pump?
Installing the valve spring on the metering pump discharge valve improves repeatability, but the most effective improvement is to install a back pressure valve at the end of the line.

3. How to adjust the back pressure valve?
1) When the metering pump is under pressure at the suction end, the pressure at the discharge end of the pump is at least 1 bar higher than the pressure at the suction end.
2) Never exceed the maximum working pressure of the metering pump.

4. If the liquid delivered is not water, how is the suction height calculated?
Divide the rated suction lift of the metering pump by the specific gravity of the metering liquid.

5. How to set the pressure of the safety valve?
The pressure of the safety valve can be adjusted within the rated working pressure range of the metering pump and must not exceed the maximum working pressure of the metering pump. The safety valve is designed to prevent overpressure operation of the metering pump. For example, if the metering pump has a maximum working pressure of 3 bar, the safety valve pressure should be set to 3 bar, or lower to ensure proper operation of the metering pump. Overpressure work is one of the main causes of damage to the metering pump.

6. How to choose the appropriate pulse damper volume?
By multiplying the metering capacity (ml) of each stroke of the metering pump by 26, the minimum volume (ml) of the pulsation damper required to reduce the pulsation by 90% is obtained.

7. Under what circumstances do you use self-priming aspiration?
1) The metered liquid is easily volatilized;
2) The specific gravity of the metering liquid is large;
3) When a higher stroke frequency is required;
4) When the metering pump is working in high altitude areas;
5) Large tanks are required for on-site applications, and self-priming by metering pumps is not feasible.

8. Can you give some advice on the choice of pump heads for metering pumps? What problems usually arise when it comes to the corrosion of the pump head/seal of chemicals? How to avoid it?
When it comes to metering pump heads, the usual problem is when measuring acid, chlorine, fluoride and hydrogen peroxide. Due to differences in drug concentration and operating temperature, it is difficult to determine the specific pump head material. When measuring fluoride, we recommend the Viton? sealed PVC pump head. For most chlorination applications, it is best to choose an EPDM sealed NP (Plexiglas) pump head. For the metering of hydrogen peroxide mixtures, only PTFE-sealed PTFE pump heads or stainless steel pump heads can be selected. The metering of concentrated hydrochloric acid usually requires a Viton® sealed plexiglass pump head. The sulphuric acid can be metered with a PTFE sealed PTFE pump head. The manufacturer of the chemical will give advice or consult the ProMinent® chemical corrosion chart to determine the compatibility of the chemical with the contact material.

9. What factors must be considered when metering liquid at the pump head?
The main considerations are the viscosity, specific gravity, vapor pressure and temperature of the liquid.