A manufacturer of compressed air systemsturned to its customers for feedback and ideas when designing its extended vertical compressor range. Bob Cheshire and Mike Higgins report.
Two years agocompressor air systems manufacturer Hydrovane launched the Mark II’s predecessor; a verticalrotary vane air compressor in three sizes: 4kW5kW & 7kW. It incorporated the highest specification of any compressor available on the market and its innovative vertical designwhich saw the direct integration of the compressor and electric motoreliminated any drive components resulting in a high efficiency yet low maintenance unit all in a small footprint.
Since the launchfactory test compressors have been on a continuous stop/start cycle and have now clocked up over 300000 stop-starts – the equivalent to many lifetimes of normal use.
Howevertwo years and more than 3600 compressors laterthe company was keen to make sure its compressors remained at the cutting edge of technology andin direct response to customer consultation; it began creating the second generation of vertical compressors.
The introduction of the initial concept was a step-change in the compressor market. Keen to maintain the core features offered by the first generation of vertical compressors but by listening to feedback from customersdistributors and most importantly service engineersHydrovane was able to identify a number of potential enhancements.
There was a common theme in all their wish lists: performance – more air for less powercombined with higher quality air and an even lower noise level. All these comments and ideas were discussedanalysed and costed and proposed design improvements were then referred back to the customers to ensure their needs had been met.
The ABS plastic panels have been replaced with a steel enclosuremaking the system extremely robust and practical yet retaining its totally unique appearance. And within this steel enclosurethe starter box now takes up a complete side of the compressor – expanding available space so that any additional equipment that may be needed for external control can be easily integrated.
On the regulated speed (RS) versionthe inverter drive will now be totally enclosed within the starterwith a controlled flow of clean cooling air for maximum efficiency and extended operating life.
A state-of-the-art electronic controller has also been added. The controller has a continuous illuminated control panel displaying air pressure and compressor temperature for clear visual control of the main operating parameters. One of the many features of this new controller is the automatic countdown to next servicefacilitating cost-effective timing of service procedures. And with service in mindthe oil filter and oil drain tap have been repositioned to the front of the compressormaking servicing both speedy and totally accessible.
Following the success of the Mark II vertical compressor in sizes 4kW to 7kWthe range is being extended to cover 11kW to 15kW and in thefirst quarter of 200718 to 22kW models will be available.
Changing from the existing horizontal to the vertical design enabled Hydrovane to directly couple the compressor and electric motorreduce the footprint and reduce noise levels. This means the compressor can be comfortably sited right next to the point of use of the airwithout a need for ear protection.
The new range is available with reduced energy venting system (REVS) technology. In the current climate of increased energy costs and the effects of global warming on the planet saving money on energy has never been more important to a business.
From recent studies undertaken by a UK Government backed organisation*it is estimated that around 20 per cent (£12 billion) – of the UK’s £60billion energy bill is wasted each year. In the case of compressed air the scenario of fluctuating air demand coupled with compressed air delivery can result in wasted energy due to the lack of understanding of a users requirements.
It is estimated that the lifetime costs of an industrial compressor can be split into the following segments.
73 per cent energy18 per cent capitalseven per cent maintenance and two per cent Installation costs*.
A compressors performance is most efficient at full load. Part load conditions can expend more power at a reduced flow output which may result in inefficient power usage. Hydrovane has developed a solution to fluctuating air demand in the form of regulated speed units (RS) with the use of Inverter technology. Inverters are commonly used in various applications from elevators to running machines and from cranes to conveyors.
Apart from the Inverterall of the other major components in an RS compressor are exactly the same as a fixed speed unit – air endmotorcooler and base frame. The only major difference being that the air end is downsized in order to give the regulated speed performance.
For example a 7.5kW RS compressor utilises a 5kW Air Enda 15kW RS compressor utilises an 11kW Air Endand so on. The motor speed can then be regulated and the Air End can run faster than 50Hz to achieve its nominal motor power.
The company’ s conventional fixed speed units operate with a relatively low motor speed of around 1450 rpm.
Rotary Vane Technology does not lend itself to excessively high motor speeds. However our Regulated Speed units work efficiently within motor speeds of 1000 to 2200rpm dependent on the model.
A pressure transducer in the air line is constantly monitoring system pressure. The Inverter then converts this pressure reading into a voltage signal and in-turn converts it to a Hz frequency. The motor speed is then regulated by the Inverter.
If there is an increase in the the system pressure and the air flow reduces then the inverter reduces the motor speed thus saving motor power. Consequently if there is a decrease in system pressure which causes air flow demand to increase then the inverter increases the motor speed to produce more air.
The Inverter drive is integrated within the starter enclosure and cooled by a filtered air flow for maximum operating life. The Inverter is also fully-interfaced with the electronic controller for simple control and greater flexibility.
A regulated speed (RS) optionis offered on a range of models in 7kW15kW22kW37kW and 75kW.
Bob Cheshire is managing director of the Hydrovane business of CompAirRedditch U.K. www.compair.com . Mike Higginsis the far east based regional sales manager for Hydrovane.
* Source: The Carbon Trust. For more informationvisit www.thecarbontrust.co.uk
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