The world of pumps is dominated by well established designs which offer good solutions to a wide range of problems. Pumps come in many sizes and operate on numerous different principles. Some pumps flourish with more difficult applications and one of these is the air operated diaphragm pump.
Imagine a situation where there is a real need for self priming, a difficult chemical to handle perhaps including some solids and an explosive atmosphere demanding ATEX equipment. The air operated diaphragm pump is ideal, and as a well established technology, these pumps are now reliable with the added benefit that they can run dry for an extended period. The pumps might only be feeding dosing equipment from barrels, but it is still a critical duty which the pump performs well and it isn’t easy to find a satisfactory alternative.
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They have their disadvantages. We all know that compressed air is expensive. When operating at low heads, the pumps require a significant air pressure to start, typically more than one bar. A pulsation damper is sometimes required to smooth the flow and the pumps can damage shear sensitive fluids. Perhaps because they run dry well, it is easy to forget them and leave them running for longer than required. We initially focus on the pump to solve the problem, but to keep it running we have a fair amount of equipment and a potentially high running cost.
There have been claims before that a new pump has been designed which sets new standards for efficiency, but however worthwhile, these have generally been evolutions of the current technology. Now a new technology has appeared which changes the standard of AODD pumping.
Tapflo UK have developed the LEAP technology, Low Energy Air Pumps, which controls air flow through the pump with a fundamentally different principle.
This technology shows efficiency improvements at all air pressures but the improvements are most marked at low air pressures. Now instead of starting at more than one bar with a possible tendency to stall at such pressures, a pump will start at as little as 0.2 bar and operate more smoothly and more quietly as well.
Mick Barnes, Managing Director of Tapflo UK who have developed the LEAP Technology says, “Some of my customers are saying to me, ‘I have to have that Technology to achieve the energy reduction targets I have been set’”. Mick’s company has carried out three years of trials with a customer and he now feels that the technology is ready for more wider use.
When the pump is used in a factory with a compressed air supply, the saving will be in electricity for the factory air compressor. When the pump is supplied to an OEM for use in a particular self contained piece of equipment, it might be the only user of compressed air and the requirement for an air compressor is dramatically reduced. OEMs often use diaphragm pumps on the back of commercial vehicles, where any weight saving allows more payload. The technology requires a 24Vdc electrical supply, which is readily available and commonly used to control the pumps via a solenoid valve. The new technology also gives smoother operation, so there should be no requirement for a pulsation damper and some more opportunities to pump shear sensitive fluids.
The LEAP Technology has allowed the pump to develop to give smooth, effective delivery at the lowest energy consumption and be reliable. The new technology can also count the number of strokes or operations the pump has carried out, allowing the possibility of planned maintenance to reduce an incidence of failure, leaks and downtime. Downtime in an automotive paint plant comes at a high price and the pumps sometimes operate in conditions where any leak is not acceptable.
Lets take a typical worked example and consider the energy savings.
- Customer X has a duty to take a solvent from a barrel and transfer 20m to the factory blending system
- Total back pressure including frictional and head pressures are 1.5 bar
- Flow required is a nominal 25 l/min
Currently the customer is using an ATEX Steel pump model TX70 with PTFE diaphragms and valve balls
Using the same pump but with the LEAP technology the benefits can be seen immediately in control, noise and air consumption as seen in the graph below.
The Area left of 1.3 bar is the area that traditional pumps do not operate in the energy is now being utilised fully.
The Standard pump requires a minimum air pressure of 1.3 bar to start and 2.8 bar to achieve the flow rate required at the back pressure of 1.5 bar
Air consumption 220 NL/min
The same pump using the LEAP technology requires only 0.2 bar to start and 1.9 bar air pressure to achieve the flow rate required at the back pressure of 1.5 Bar
Air consumption used 160 NL/min
Air saving 60 NL/min
Cost Saving Calculations
(Cost calculation based on BCAS fact sheet No. 010)
As a rule of thumb it is generally accepted that the cost for compressed air ranges between £0.01 and £0.03 per cubic meter (m³) of air. The exact figure will depend on several factors such as unit cost of electricity, compressor type and efficiency, but those companies that have gone through the process of establishing their specific cost normally end up with a figure between these values.
Using these values with the example given above we can calculate that the cost saving for the LEAP pump per minute would be;
Volume of air (m³) x £0.01 or £0.03
0.06 x £0.01 = 0.0006p per minute
To 0.06 x £0.03 = 0.0018p per minute
If we consider that the pump would run 8 hours per day, 5 days a week and 48 weeks a year, we observe a cost saving of
0.0006p x 60 x 8 x 5 x 48 = £69.12
To 0.0018p x 60 x 8 x 5 x 48 = £207.36
Other Benefits Seen
- Almost no pulsation
- Greater control
- An immediate feedback if the diaphragm ruptures or there is a loss of air pressure.
- No requirement for a separate solenoid valve to turn the pump on or Off as this is built into the technology.
The LEAP technology is also available in a Hydraulic powered version. This is now being used in markets where a traditional double diaphragm pump is required due to gas in the liquid, solids, dry running or self priming is required but the use of an electric powered version is beneficial, by coupling the pump directly to a standard hydraulic power pack. Tapflo UK have been able to supply electricly operated double diaphragm pumps with pressures of up to 26 Bar. This unique solution offers full control and a very cost effective solution. Available in many different materials, Tapflo UK have a pump that will suit your application.
The LEAP technology has a patent and is UK designed and manufactured.
It is very easy to leave an air operated diaphragm pump running dry. These products will run dry for an unlimited period, though when running dry they will speed up wasting energy at an incredible rate, diaphragm life can also be an issue. Tapflo UK have also developed the only fully Pneumatic ATEX approved run dry protection device, branded the ‘Guardian’ which is very effective for this requirement. It is hard to calculate the efficiency saving from a dry run protection device, but if the pump ran usefully for a few minutes and was forgotten overnight, the saving is clearly substantial.
Thus we can see that a revolution is taking place. Anyone who needs to be convinced only needs to see a demonstration of two pumps, one using the new technology and one the old. The new pump starts first as air pressure is increased and is running well when the older one only just starts to pump at a much higher pressure. The demonstration is clear.
Tapflo UK Ltd
Phone: +44 (0)2380 252325 | Fax: +44 (0)2380 269016
Victory Close | Chandlers Ford | SO53 4BU | United Kingdom
www.tapflopumps.co.uk
sales@tapflopumps.co.uk
