Spare parts
When buying fans, it is important to check the manufacturer’s ability to maintain a stock of spare parts. The supplier should be able to provide a quotation for
• commissioning spares,
• spares for 1 year,
• spares for 2 years,
• insurance spares.
Spares quotations will include delivery times. The spares quoted will be the parts which the supplier knows from experience will wear or become damaged. Insurance spares may be required if the fan is on a critical service and space is not available for stand-bys. Spares are costly. Some manufacturers may offer a discount if the spares are purchased with the complete fan. If the quotation does not mention discounts, ask.
The assessment of spares requirement is dependent upon many factors; the process gas, the operating conditions, the number of hours of operation per year, delivery times for spare parts from the manufacturer, storage costs, etc. Table 18.7 shows suggested spares which should be held according to the number of identical fans.
|
Spare parts |
Number of fans |
|||||
|
2 |
3 |
4 |
5 |
6 |
8 |
|
|
Number of spare parts |
||||||
|
Impellers |
1 |
2 |
2 |
3 |
||
|
Shafts |
2 |
2 |
2 |
3 |
||
|
Seals |
2 |
2 |
2 |
3 |
3 |
4 |
|
Inlet cones |
1 |
1 |
2 |
2 |
3 |
|
|
Vee belts (set) |
2 |
2 |
3 |
3 |
4 |
|
|
Bearing races (set) |
2 |
2 |
3 |
4 |
||
|
Gaskets |
1 |
2 |
2 |
3 |
|
Table 18.7 Proposal for stocking spare parts for industrial fans |
The fan supplier should also be asked about the supply of spare parts if a fan model is made obsolete and current production ceases.
When failure of the fan involves risk of damage, for example the possibilities of flooding or vital cooling systems being put out of action, a stand-by unit with an automatic starting system should always be installed if space allows. When a number of fans of the same size share a service, it is a prudent to have one complete unit in reserve for change-over in the event of a breakdown or in the case of a planned overhaul. Naturally the duct connections, electrical installation, etc. should permit really rapid change-over with the minimum of inconvenience and effort.
If overhauls and repairs are to be performed by the user’s staff, it is also important that the tools required for the purpose should be obtained. Fan suppliers can make the necessary recommendations. If special tools are necessary, the fan supplier should quote costs for the tools when quoting for the fan. The use of unsuitable tools frequently results in more serious damage than that for which measures were to be taken.
Machinery Directive 89/392/EEC (Amended 98/37/EEC). This Directive is fully implemented into UK law by means of the Supply of Machinery (Safety) Regulations 1992 (SI 1992/3073) as amended by The Supply of Machinery Safety) (Amendment) Regulations 1994 (SI 1994/2063).
ATEX Directive 94/9/EC, Equipment intended for use in Potentially Explosive Atmospheres.
PrEN 14986:2005, Design of fans working in potentially explosive atmospheres.
ISO 12499:1999 BS 848-5:1999, Fans for general purposes. Special for mechanical safety (guarding).
BS 1440:1971, Endless Vee belt drive sections (withdrawn replaced by BS 3790
BS 3790:1981, Specification for endless wedge belt drive sections and endless Vee belt drives (technically equivalent to ISO 155, 254, 1813, 4183, 4184, 5292).
AMCA 202-98, Troubleshooting.
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