Key points
When innovative processes are researched and theories are tested, often small scale equipment is designed and produced for proof of concept. This can be to test theories or for limits to be checked, or the process refined before a full scale plant is built.
Our latest project involves a dielectric coolant pump we supplied as part of a client’s test rig. They were looking to test a dielectric coolant in a controlled environment in several countries, meaning that the pump would have to work at dual frequencies.
A dielectric fluid is usually designed to prevent and reduce electric discharges by suppressing arcing in electrical equipment, as well as acting as a coolant for processors, transformers or other electrical equipment.
When looking for a cooling pump there is a number of criteria which determines the best pump – the required duty points, the daily hours of operation, the viscosity of the fluid being pumped and how friction losses may vary with pipe runs.
What’s more, different pump types will give different results. A positive displacement pump will transfer the same amount of dielectric fluid even if pressure losses change, for instance if the number of circuits needed to be cooled increases such as when valves are opened.
In contrast, a centrifugal pump flow will change according to the pump speed, with pressure reducing as speed is reduced.
The materials used for circulation pumps can vary from cast iron for use with oils, to stainless steel, duplex metals or non-ferrous metals when used with more aggressive fluids, or to prevent cross contamination with high cost fluids, and ensure cleanliness.
In short, any pump specified for cooling should be engineered to meet any duty points demanded by the application – at both peak and off-peak demand.
Why we specified a positive displacement pump
At first, our client asked for a centrifugal pump for this application. However, we recommended that the customer look at a positive displacement pump for this process.
We selected a positive displacement pump because it would ensure flow rates would be proportional to speed, and discharge pressures would be constant. This would make conclusions much easier to be drawn than a pump in which both flow rate and pressure changed during the testing process. We would make these assessments using pump performance curves.
What is a pump performance curve?
Pump performance is governed by pressure losses in the system, with pumps producing different flows and pressures depending on conditions at the inlet. A pump performance curve is simply a diagram showing the flows and differential pressures being produced by a pump.
To enable us to specify a pump for a particular application and process, we need to know the:
1. Application
2. Fluid being pumped
2. Flow and pressure required
4. Viscosity of the fluid and its specific gravity
6. Temperature
7. Power available and the power medium driving the pump
Centrifugal pump performance curve
Centrifugal pumps are used in 70% of pumping applications, and their curves are generally a half-moon shape as shown above. The highest point on the left shows highest pressure but lowest flow. The far right end of the curve shows the highest flow but lowest pressure. The duty point is marked with the efficiency indicated in percentage.
Positive displacement pump performance curve
As you can see, a positive displacement curve is actually a straight line. This is because, unlike a centrifugal pump, a positive displacement pump flow is proportional to RPM and does not decrease with pressure. In addition, a positive displacement pump curve usually has a separate axis for viscosity, where the pump will show a flow against viscosity as below.
Specific client requirements
For this particular application, the client requested that the pump be able to operate at both 50Hz and 60Hz as the test rig was being used in both the UK and the US.
They also wanted to easily control the pump’s performance. To achieve this, we specified the pump with an integrated inverter allowing operators to adjust pump speed directly on the pump, without having to pay for an external control panel. This would enable low cost trials to be carried out without affecting the validity of the results.
If you’re developing a new product or machine, are involved in the testing of a new fluid or are looking for dielectric cooling pumps for your process, speak to North Ridge Pumps to see how we can help.
North Ridge Pumps
- 01773302660
- sales@northridgepumps.com
- http://www.northridgepumps.com
- North Ridge House 3 Chrysalis Way Eastwood Nottinghamshire NG16 3RY GB
About us
North Ridge Pumps are an independent manufacturer and distributor of pumps. Having been established since 1998, we have a vast array of experience having become accustomed to supplying pumps for most processes.
We work within a range of industries both UK and Internationally, specifying pumps for a wide variety of applications from the transfer of corrosive and aggressive chemicals, to dewatered sludge, viscous grease, resin, glues, food and Seawater.
Our pumps range from standard centrifugal and multistage pumps, to immersed and process overhung solid handling pumps. We also supply a wide range of positive displacement pumps including Vane, Piston, Progressing Cavity and Peristaltic enabling us to specify more than one solution for your application, but also ensuring the majority of applications remain within our reach.
We offer the following services:
Technical support – We know at times pump selection is difficult. Pump selections are made with confidence by technical sales engineers who understand your process, ensuring equipment is engineered beyond your needs.
To select the correct technical solution for your requirement, longevity of design is prioritised. If there are existing issues you need assistance with, we work with you to solve these which could be high maintenance costs, frequent service periods, repeated equipment breakdown leading to lost revenue, inconsistent flow rates, clogging or where pumped product is inconsistent.
Application experience – Due to our 20 years of application experience we work with you to ensure our pumps operate according to your desired application. Our experience means we have most likely provided a solution for a similar process previously. With proven results, we know how to achieve your outcome sooner.
As our pumps are completely configurable, we design pumps with materials according to your requirement, and to your required duty point. Pumps are engineered specifically for your process whether they be baseplate mounted, within a mobile frame or in kit form with couplings, hoses, and dispensing nozzle.
Industry knowledge – We have a thorough understanding of a range of industries through experience from supplying the offshore oil and gas market, to paper mills, chemical plants and food manufacturers to name a few.
We not only understand the importance of downtime but also what each process requires and how small design improvements specific to the nature of your industry and application can reduce downtime, facilitate maintenance and improve longevity.
If you have a process or application you require a pump for, or a process which requires improving, get in touch to see how we can help.
What we do in a nutshell
Pump Specification & Supply
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