Corken Vane Positive Displacement Pump from Kelair Pumps Australia

Case Study
Sales Engineer Alex Calodoukas (NSW)

Corken solves a batching system problem

One of our customers had a requirement for a new batching system for solvents. Fortunately this customer already had existing systems that were in a sense similar, so we could use those as a guideline.

Centrifugal pumps were previously used for this batching exercise, but the pump was to have different suction conditions. This pump would have the requirement of suction lift. So centrifugals were out, and a positive displacement pump was to be used. We selected one of the Corken Vane pumps for their ideal suitability for thin, light solvents, and for their suction lift capability.

In this application (unlike the centrifugal pumps on site) the batch size for the pump would vary greatly. The duty was to fill 200L drums, and also 20L drums with the same pump - both with some level of accuracy. The immediate problem was how to select the optimal flow rate. If we selected 15 seconds to fill a 20L drum, then it would take 150 seconds (2.5 minutes) to fill a 200L drum. However that time frame would be far too long when filling large quantities of 200L drums in batches. On the other hand, selecting a speed of 15 seconds to fill the 200L drum would only allow 1.5 seconds to fill the 20L drum. That would lead to tremendous inaccuracies and overflows (and therefore hazards) with the 20L drums, due to solvent spills at high flow rates. And we couldn't use a variable speed drive for the motor because being a Class 1 Zone 1 area, the drive would need to be housed indoors elsewhere requiring extensive special cabling at a cost premium. We needed another option.

At least we could use a similar batching device to those already in place at the site. The photo shows yellow and grey batching system suitable for Class 1 Zone 1 Hazardous Areas. It has manual controls to set the batch sizes required. Attached to that would be a manually operated filling nozzle.

Kelair fabricated a trolley baseframe for mobile use around the site. The batching system was mounted up high on a heavy duty support with provision for an emergency stop button alongside. The pump was mounted underneath with associated pipework. The pump had a Class 1 Zone 1 motor to drive it (also with non-sparking coupling). Now there was just the problem of selecting the best suited flow rate.

The way the batching system is set up, is it has a manual valve within it to shutoff the flow when batch size is reached. The longer the shutoff period, and the higher the flowrate, the more recirculation through the pressure relief valve (attached to the pump head). The more recirculation, the more heat generated within the valve.

With solvents on a hot summer's day and continuous stop/ starts for the 20L drum fills, we wanted to minimise the amount of heat generated through the valve by recirculation. We opted for a gearbox with manually operated handwheel to give a six-to-one (6:1) turndown ratio. That meant that we could select an ideal flow rate for 200L drums, and by simply turning the hand-wheel, reduce the speed for accurate low flow rate batching with 20L drums. All problems solved.

The system has been operational now for some months.