Air Compressor, Air Lines, Air tools -

Choosing the Right Compressor for a workshop

The humble air compressor is a critical component in any workshop. Down time or inefficient running of this workhorse will undoubtedly lead to delays and a significant impact in the shops profitability. Proper maintenance of this valuable piece of equipment is critical, but selecting the right one to begin with can help to minimise problems in the future.

There is a fair bit to consider when replacing an old compressor or opening a new facility. You need to carefully weigh up 3 major factors. 1. Current requirements, 2. Future shop expansion 3. Budget.

Estimating your current and Future needs:

When selecting the right size compressor you need to accurately calculate your current needs and estimate any expansion you expect to experience within the working life of the compressor. The service life of the compressor will vary depending upon the type and quality you choose. The dealer of the compressor will help you identify expected service life.

In order to estimate current and future needs it is necessary to find out the actual air consumption of the equipment required to run off the compressor. The supplier of your air tools can help you get this information, but a word of warning, make sure you get the “Actual” air consumption and not the “Average”. There is a significant difference in these numbers and if you base your requirements on the “Average” figures you will find you have underestimated your requirements by as much as 50%.

Once you have, as accurately as possible, identified you’re current and future needs add a factor of 30% to this figure. By doing this you will ensure the compressor is never overworked when under maximum expected load. This will result in a longer service life and lower maintenance cost.

This additional factor of 30% will allow the compressor to cycle, which dramatically aids in the cooling process of the pump and minimises oil bypass through the piston ring into the air line. It will also minimise the heat generated from the compressor and reduce moisture contamination.

 Choosing the Right Compressor Type.

Once the size of the compressor is determined a decision can be made, based on efficiency and budget, as to what type of compressor to install.

Most workshops will need 3 phase power to drive a suitable compressor. Compressor sizes from about 20 to 30 cfm are normally standard piston powered, however a screw compressor is most likely be the best option for larger output.

A standard piston compressor is normally powered by a motor connected to the pump by means of V belts. The pump can consist of one, two or three cylinders that will compress air and store in it a receiver tank. This system can be quite noisy and a suitable insulted position, in a dust free environment should be identified. Sound insulated cages are available to minimise noise pollution.

If you budget allows, the more practical choice for larger air requirements is a screw compressor. The most common size for the average panel shop would be an 11kw (15HP) unit supplying approx 58cfm free air delivery.

Screw compressors are extremely quite and offer longer service life provided standard prescribed maintenance schedules are adhered to. Like a piston type, screw compressors are supplied with a suitable storage receiver.

Regardless of Compressor types it is highly recommended that a quality refrigerated drier system as well as pre filters and after filters are installed to eliminate contamination in the airlines. It will cost you a little more at installation but it will pay dividends over time by reducing wear and tear on air tools and contamination of job

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