A finger on the pulse
28 October 2013
Status-based maintenance can cut costs and improve investment security and, with modern diagnostic tools, the need for rigidly fixed maintenance intervals and precautionary replacement of compressor parts can be avoided, explains Andy Westwood, service manager at BOGE Compressed air Systems
When making investment decisions, it has long been standard practice to take into account not only the purchase price, but also the costs incurred during the service life of the machine, for maintenance and replacement parts, for example. What if there was a way to reduce these lifetime costs by extending maintenance intervals – while not only maintaining but also increasing operational reliability? Innovative diagnostic tools are the key.
In the past, maintenance intervals were usually fixed in advance and components were replaced as a preventative measure after a specified running time. This approach comes at a price, however. When calculating replacement intervals, the manufacturer usually incorporates a safety factor. To reduce the risk of damage, the figure is based, at best, on the average life expectancy of the parts. As a rule, the following applies: the more expensive and important the component, the higher the safety factor. This means that important components tend to be replaced before they are worn, which often results in premature maintenance and substantial costs.
There is huge, previously untapped potential for increasing efficiency – flexible, status-based maintenance. Modern diagnostic methods mean that it is no longer necessary to replace high-value components, such as compressor stages and motors, at previously defined intervals. This results in cost savings for the customer, since replacement intervals are increased.
BOGE believes this method offers the best of both worlds: even greater reliability at a lower price. Making maintenance intervals more flexible is the latest advance in a long-term trend to improve efficiency. This trend also included the increased use of electronics in compressors, aimed at optimising switching behaviour and reducing costs and energy consumption by using intelligent control systems. The data already available in the compressor or in a master control system can be collected and – after correct interpretation – can be used to provide information regarding wear on the machinery and its components. This is the case if this data is linked to additional information, such as information provided by the vibration sensors of BOGE’s newly developed 'effilence' compressor stage. By monitoring vibration, the status of the rolling bearings is determined on a continuous basis. These are then replaced or renewed only when the diagnostic data indicates that this is necessary. The expensive, preventative replacement of parts is dispensed with – without increasing the risk of an unscheduled shut-down of the plant.”
Local or remote control
Monitoring can take place in two different ways. One method involves checking the individual compressor to determine its status or to record events that indicate a borderline state of wear and the imminent failure of a component. BOGE service technicians carry out these checks using a mobile diagnostic device. The other method allows remote monitoring. In this case, several compressors can be integrated into a monitoring system and additional early warning values can be defined. The advantages: an overview of the statuses of all the operational compressors and treatment components allows optimal scheduling of servicing appointments; also, corrections can be made, even during normal operation, to ensure that the plant continues to run as efficiently as possible. Unexpected stoppages and shut-downs are minimised.
The combination of status checks and remote monitoring enables BOGE to offer service and contractual arrangements that are tailored to the customer’s needs. With the BOGE bestcair service contract, customers have a five-year, no quibble warranty on all components of the compressor. New products are constantly being added to the range of service contracts – an all-inclusive, worry-free package will soon be available for all dryers in the DS range. In future, BOGE service contracts will be based on a more modular concept. Customers can select the modules that are most important to them, such as remote maintenance and fault diagnostics via airstatus, and add these to their service contract as additional modules without immediately having to sign a full service contract.