Views: 0 Author: Site Editor Publish Time: 2024-06-05 Origin: Site
Metering pump in the metering medium and working pressure to determine the case, by adjusting the stroke length L and stroke frequency F can be achieved on the two-dimensional adjustment of the metering pump output. Although both stroke length and frequency can be used as adjustable variables, metering pumps generally regard stroke length as coarse adjustment variables in engineering applications, and stroke frequency as fine adjustment variables: adjust stroke length to a fixed value, and then realize fine adjustment by changing its frequency to increase the flexibility of adjustment. In relatively simple applications, it is also possible to manually set the stroke length, using only the stroke frequency as the adjustment variable, thus simplifying the system configuration.
1. metering pump regular analog/switch signal adjustment mode
In process control applications, 0/4-20mA analog current signals are used as a standard for signal exchange between sensors, controllers, and actuators. Metering pumps with external control function mainly use this method to achieve external adjustment of stroke frequency and stroke frequency. The metering pump position servo mechanism is the most common method to achieve stroke length adjustment. The integrated servo mechanism is designed to directly receive the 0/4-20mA control signal from the regulator or computer, and automatically adjust the stroke length within the range of 0-100%.
Relatively speaking, there are many ways to achieve stroke frequency adjustment, including variable frequency motor control and direct relay contact control. The variable frequency governor controlled by 0/4-20mA current signal drives the metering pump motor to run at the required speed to adjust the stroke frequency. For electromagnetically driven metering pumps and some motors, an external contact signal can also be used to adjust the stroke frequency.
2. metering pump base type control mode
In some special occasions, such as pH adjustment, the automatic metering pump acts as an actuator, adding acid or alkali under the control of the regulator. In order to simplify the system configuration and improve reliability, the embedded control system with microprocessor as the core is directly integrated into the metering pump, and only one external pH sensor can form a complete adjustment system. The basic smart metering pump concept can also be used to control other process parameters, such as oxidation reduction potential (ORP) and residual chlorine concentration regulation.
3. Program control of metering pump settings
Due to the internal integration of micro-processing computer, the adjustment and operation performance of some metering pump products have been comprehensively improved. In addition to real-time metering and flow adjustment according to external control commands, it also provides functions such as quantitative addition, time series trigger program addition, event series trigger program addition, time series trigger program addition, etc., and can also provide useful information such as the total amount of pumped fluid, the remaining stroke number of the metering pump, the amount of fluid to be delivered, the set stroke length and other related working parameters.
Real-time clock, dosing metering pump according to the pre-planned task list, metering pump can add working fluid at the specified time according to the set number of strokes or time. The time can be flexibly set according to the cycle of hours, days, working days, public holidays, one week and two weeks. The program mode triggered by the sequence of events enables the metering pump to add working fluid according to the pre-set number of strokes or time according to the pre-planned task list according to the real-time trigger event.
The above two methods can be organically mixed to complete the more complex time-event hybrid trigger mode, with a maximum of 81 events.
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