Airchannel variable-speed compressor fits the bill

Edited by the Engineeringtalk editorial team Oct 15, 2008

Airchannel was asked to conduct an air audit to identify weaknesses in Henry Bell and Co's (Grantham) ageing air system, eventually supplying a Worthington Rollair variable-speed compressor.

Henry Bell and Co is supplier of flaked cereals, pulses and seeds to the animal and pet food industry.

Its compressors were at least 20 years old and Airchannel believed they were inefficient and uneconomic, with no automatic control functionality.

The audit of the compressed air system was carried out using data-logging equipment.

An intelligent data-logging device was attached to the system to monitor the quantity, as well as the pattern of usage of compressed air over a working period.

The data was analysed to produce a pattern of actual site demand.

The results of the audit were so conclusive that Henry Bell was determined to restructure its compressed air supply completely.

Airchannel was awarded the turnkey contract to provide the best equipment in terms of low energy consumption and air availability.

For a system to operate energy efficiently, the supply of air from the compressor has to match demand, which will rise and fall over different shift patterns, and so Airchannel promoted the advantages of introducing a variable speed compressor, as the major single cause of energy wastage in compressed air systems comes down to air being generated but not used.

A conventional fixed-speed compressor producing zero compressed air can still be using 20 to 70 per cent of full load power.

Airchannel proposed a Worthington Rollair compressor from their V range of variable-speed compressors.

These can reduce compressed air production.

Whatever the pressure requirement the Rollair V will precisely match load to demand by constantly varying the motor speed to ensure the most efficient use of energy - no offload running.

The system balances air supply to meet fluctuations in plant demand and provides the appropriate volume of air across the entire plant.

The Worthington compressor is much simpler with fewer moving parts for easier maintenance and electronic controls reduce stress on the components, for even longer life.

One of the advantages of the Rollair compressor is that the motor is placed directly under the cooling air turbine.

This means the motor has a constant flow of cooling air across it, resulting in low motor temperature even at low speed.

It contributes to a longer motor life.

Moreover, air cooling turbine gives low rotational speed, superior air flow, 30 per cent lower energy to a conventional motor driven fan, and a very low noise level.

Being small, the inverter is vertically integrated into the cubicle of a standard Rollair canopy.

Thus it has one of the smallest prints in the market today.

Innovations in the field of electronics has lead to frequent improvement of components.

In addition to supplying the compressed air function, Airchannel also installed a Maxigas nitrogen generator, manufactured by Domnick Hunter, allowing Henry Bell to make their own gas on site, cost effectively satisfying their nitrogen gas requirements.

All associated pipework was also provided under the contract.

There are financial incentives available and Airchannel maintains that the resulting energy cost savings means the new equipment is self-funding over a very short period.

For Henry Bell and Co there was also the possibility of obtaining an interest-free loan under the Carbon Trust's energy efficiency programme.

Airchannel researched this funding option and obtained a four-year interest free loan from the Trust.

Henry Bell is already benefiting from reduced down-time associated with changing Nitrogen gas cylinders through an on-demand high purity food grade supply.

It is also safer than high-pressure containers as man-handling is eliminated, offering exceptional food grade nitrogen at a controlled flow, pressure and purity.