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COMPRESSORS & COMPRESSED AIR NOW IS THE TIME TO TACKLE COSTLY LEAKS
Mik Rhodes, Technical Development Manager for Thorite, shares low-cost ways to avoid compressed air leaks and achieve long term savings
ir leaks can be extremely costly, wasting as much as 30% of a compressor’s output. They can occur at multiple points in a system, from couplings and hoses to packings and thread sealants. They cause the compressor to become overloaded, which can reduce equipment efficiency, decrease its lifespan and cause excess energy use. The inevitable extra costs in terms of downtime, maintenance and capital expenditure, not to mention excess energy use at a time of soaring prices, is a compelling incentive to tackle what is a relatively easy problem to fix.
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company paid a £200 up front deposit for the dataloggers, on the agreement it would be fully refunded if the compressor was found to be operating efficiently and no energy saving solution was required.
However, many companies choose not to identify compressed air leaks in their systems, and those who pay to have an air leak survey carried out by skilled professionals often do not act upon the repairs which are subsequently recommended. This is a ‘lose- lose’ situation which can lead to significant financial losses being accrued year on year. However, there are ways to avoid waste which won’t make a dent in company finances and will deliver long term operational improvements. They can be implemented even without an air leak audit and are therefore ideal solutions for these straitened times.
Every generator consumes energy when it is on load. Data logging is the simple process of monitoring how much energy the compressor is using, to establish how efficiently it is working.
The data logger is simply clipped onto the compressor, requiring no downtime, and a graph detailing how many KW of energy have been used is generated. Analysis usually takes around 7 to 10 days to complete and will give a clear indication of whether a compressor is operating productively, or being overworked and racking up excessive energy costs. A solution can then be suggested to save energy and improve the operational efficiency and lifespan of the compressor.
Thorite carried out data logging on a 70KW compressor on behalf of a tissue manufacturer. This was agreed on the company’s standard ‘no win no fee’ approach to data logging services. The
10 FEBRUARY 2023 | PROCESS & CONTROL
The results revealed the compressor was overworked and inefficient. Thorite recommended that the 70KW compressor was replaced with a variable speed, 90KW compressor. This required a £55,000 capital investment, spread over a three-year payment plan. However, the company saved £40,000 a year on energy costs and achieved a return on investment within 18 months, with ongoing energy savings.
Most machines experience some element of leakage, often in tiny amounts, for example at pipework connection points. This leakage becomes an issue when the airline is left blowing while a machine is not in operation, and if more serious leaks are left unrepaired. Put simply, if you don’t switch the compressor off when the machine has stopped, you are effectively running it to feed the leaks.
Detecting leaks by normal visual or audible methods can be ineffective, especially when they are small and set in the context of a noisy plant environment. A compressed air leak survey, carried out by qualified engineers using specialist thermal imaging equipment, is necessary to pinpoint where leaks are occurring.
As many leaks are small, they might not appear to present a major problem. But if there are multiple leaks on a number of machines across an entire plant, the costs in wasted energy can really start to add up. Take the example of a compressor which was running for 4,680 hours a year at 7.5 bar, and where electricity costs were 41p/kWh. A compressed air leak detection survey revealed a total of thirteen 0.5mm leaks, each resulting in an estimated loss of 0.2 litres of air per second, and three 1.5mm leaks, each losing 1.8 litres of air per second. The combined estimated cost of these leaks was £6,396 a year.
Whilst a full leak survey is the ideal solution, this potentially costly situation can in fact be partially remedied for as little as £60. The solution is a solenoid operated isolation, or shut-off, valve, wired into the compressor’s start-stop button. It controls the air supply to a machine – automatically shutting down the compressor when the machine it is powering stops. This removes the need for operatives to shut the compressor off manually and therefore removes the risk of the airline being left blowing unnecessarily. In the current financial climate, it’s important to remember solutions which can drive outgoings down without breaking the bank are available. The time has never been more right to investigate them.
Thorite
www.thorite.co.uk
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