Because of the many unique features of Depo metering pumps, its application also has the following aspects to pay attention to:

1. Energy storage device should be used

Because the Depro metering pump is a double-cylinder single-effect reciprocating pump, the pulse rate of its flow working pressure is large. In order to better clean the pulse, improve the stability of the flow working pressure, and reduce the level of pipeline vibration and harm to the performance, it is generally proposed to install an energy storage device with reduced pulse at the reciprocating pump outlet. Sometimes, in order to better absorb the suction characteristics of the inlet, an energy storage device is also installed at the inlet. The capacity of the accumulator is naturally heavier and better from the point of view of cutting the pulse level, but the larger the more uneconomic development, so it should be adjusted in the scope. The capacity selection of the metering pump accumulator generally follows: the metering verification working capacity (mL) of each one or four strokes is multiplied by 26, and the small capacity (mL) of the pneumatic control valve required to reduce 90% of the pulse can be obtained.

2. Flow regulating mechanism 

Metering pump flow regulation is completed by the driving force of the pump travel arrangement adjustment mechanism (naturally can also be completed according to frequency control to adjust the flow). The travel arrangement adjustment mechanism has two methods of electric adjustment and manual adjustment, the core content of these two methods is consistent, electric adjustment is on the basis of manual adjustment plus a set of electric regulator to replace the manual actual operation. At present, the regulating mechanism in our country generally has the following types: N-type shaft mechanism, bow type wheel mechanism, roller mechanism, camshaft mechanism and so on. The application of the flow regulating mechanism will not be limited by starting or shutting down, and it should be jammed after the adjustment, so as to avoid drifting of the mechanism parts caused by vibration and endangering the measurement verification accuracy. In general, the travel arrangement matches the large rated flow rate, and the travel arrangement matches the zero flow rate when the travel arrangement is zero, and the linear transformation is related.

3. Pneumatic diaphragm pump three valve application

The three valves of the pneumatic diaphragm pump refer to the valve, the exhaust valve and the oil supplement valve, which are the key components of the hydraulic transmission end of the metering pump. Whether the proper application of the three valves is related to the normal operation of the diaphragm metering pump and the accuracy of the metering verification. The valve is used to avoid the working pressure in the pump chamber is too high to maintain the safety of the pump and the equipment. Before leaving the factory, the pump manufacturer has already set the jumping working pressure of the valve according to the working pressure of the pump rating. The oil filling valve is used to fill the material in the work of the hydraulic press chamber, and the exhaust valve can discharge the vapor body in the material in the work. When applied, it is generally necessary to adjust to prevent too much oil or too much oil during air discharge (wechat public number: pump manager).

4. Conditions that are likely to affect the accuracy of metrological verification

The following main parameters are likely to cause harm to the accuracy of metrological verification:

(1) The flow rate of the tested liquid state.

(2) The primary characteristics of the liquid to be measured, such as organic chemical corrosion, viscosity and proportion.

(3) Back pressure of system software.

(4) The relative height of suction.

5. There are other necessary options, such as PLC control, monopulse control, flow monitoring and timer.

6. When the metering pump has working pressure at the suction pipe end, the working pressure at the discharge end of the pump is 0.1MPa higher than the working pressure at the suction end. In some special cases, such as negative pressure at the outlet, it is proposed to install a regulating blow-off valve at the outlet.

7. Be sure to ensure that the outlet working pressure does not exceed the large pressure of the pump, and it is advisable to equip the outlet pipe with maintenance equipment such as speed control valves.