Consistent Gas-Free Metering of Liquids
Gas-emitting media in metering applications can often reduce pump output or even prevent the pumped medium from being delivered. To avoid this situation, the pumps generally need to be bled manually in such applications.
delta diaphragm metering pump with optoDrive
This procedure can be performed simply, conveniently and safely with the delta diaphragm metering pump with the new venting module from ProMinent. The module detects the formation of gas bubbles in the pump head and eliminates them in good time, ensuring processes are at no time adversely affected or disrupted by inadequate metering lines.
As the result of chemical disintegration, many chemical substances, such as sodium hypochlorite (NaOCl) or cleaning agents, form gas bubbles that collect on the intake side of the pump head. The larger the gas bubble, the less fluid can be delivered. Vacuum tanks or receiver vessels that collect the gas before it reaches the pump head are normally used to eliminate such effects.
The correspondingly adapted stroke setup of the delta metering pump makes such upstream collecting vessels superfluous. A slow intake stroke setting suppresses gas emissions without the need for additional equipment.
Nevertheless, the formation of gas bubbles in the liquid end of the pump cannot be fully avoided. Should bubbles form, they are detected by optoGuard, the integrated injection point monitoring facility, and shown with "Airlock" on the pump's LC display. As soon as this message appears, the pump can be bled manually via the coarse/fine vent valve. However, the current process can be severely disrupted by inaccurate metering quantities before manual venting takes place.
Automatic Venting Function
A new venting module for the delta diaphragm metering pump effectively ensures the metering line is not impeded by air or gas bubbles in the pump head.
Optionally, the venting function is executed periodically and/or after airlock detection. As soon as a gas inclusion is detected, the airlock function automatically starts the venting cycle. The gas collected in the pump head is directed via a separate line into an additional reservoir. Unlike a permanent bypass as used in many applications, the new venting module from ProMinent ensures that the venting procedure is carried out only when there are gas bubbles in the pump head.
This is particularly advantageous when a medium such as hydrogen peroxide (H2O2) for instance is not to be diverted via a bypass for safety reasons.
As a precautionary measure, gas bubbles in the pump head can also be removed periodically to ensure automatic venting does not interrupt running processes. Geared to the process downtimes, the delta operating software can variably set the venting intervals from 1 minute through to 1440 minutes.
Ex-Factory or Retrofit
On request, the delta pump can be equipped with the venting module already at the factory. A retrofit kit, consisting of a solenoid valve, relay module and installation material such as cables, connectors and adapters, is available for upgrading delta pumps already in use to the automatic venting function.
After installing the venting module, the operating software of the delta solenoid metering pump automatically recognises the retrofit components. The venting intervals can be set individually in a new submenu just as easily as programming the metering quantities.
Source: ProMinent GmbH
