The capacity ranges between 50-420 l/h at a max. backpressure of 4-16 bar. The output can be adjusted by a self locking rotary knob in 0.5 % steps via the stroke length (5 mm).
The reproducibility of the metering is better than ±2 % in the stroke length range of 30% - 100% given defined conditions and correct installation. (The notes in the operating instructions must be observed.)
The rugged, corrosion-resistant metal-plastic housing is combined with three gearbox ratios, two liquid end sizes and two liquid end materials. The Sigma control type (S2Ca) facilitates control via contact or analogue signals (e.g. 0/4-20 mA) which ensures a good adaptation, also to different metering tasks.
For safety-technical reasons, suitable overflow guards are to be installed in all motor metering pumps without integrated overload protections.
Sigma Basic Type (S2Ba)
The Sigma Basic type is a motor driven metering pump with no internal electronic control system. The S2Ba offers a variety of different drive options in both the three phase standard motor (standard: IP 55) or the single phase AC versions. We also supply metering pumps with ATEX-approval for use in EXe and EXde zones.
Different flanges are always available so that customers can use their own motor to drive the pump.
Sigma Control Type (S2Ca)
The Sigma microprocessor version (standard IP 65) allows rapid and reliable adjustment to fluctuating metering requirements.
The controller has the same control panel as the gamma/ L metering pump.
The microprocessor controller of the Sigma pumps, featuring the optimum combination of variable AC frequency combined with digital stroking frequency, ensures exact metering even in the lower minimum range due to individual stroke control.
The individual pump functions are simply adjusted using the five programming keys. A backlit LCD indicates the current operating status, LEDs function as operation or fault indicators and fault indicator or pacing relays monitor the pump function.
Central or decentral adjustment is possible with PROFIBUS® and/or an integrated process timer.
Diaphragm Failure Indication (A)
The liquid end may be supplied with an optional safety diaphragm.
A plastic chemical resistant end disc separates the drive housing from the liquid section, and protects the drive against corrosion in case of diaphragm rupture. The new diaphragm rupture system means that the liquid section is hermetically sealed in the event of diaphragm rupture.
This has the great advantage that the feed chemicals cannot escape from the pump. In association with the S2Ca, diaphragm rupture is simultaneously indicated via the LCD. At this point it is possible to opt for continuation of the metering, or to stop the metering pump.
Integrated Relief-/Bleed Valve (B)
A liquid end variant with integrated hydraulic relief valve is optionally available for pressure ratings 4, 7,10 and 16 bar. It protects the pump against overload and potential damage with no additional installation.
This represents a considerable saving to the operator.
The integrated pressure relief valve offers the further advantage of effective bleeding of the injection valveduring intake.