1.6.3 Stock of spare parts
Stock of spare parts for pumps
When buying pumps it is necessary to inquire fully into the supplier’s resources with respect to spare parts management. The delivery should include a list of spare parts with position numbers. The purchase of a certain amount of spare parts, which are usually expensive, can be advantageous in connection with the purchase of the pump unit itself, but the difficulties of knowing in advance what will be required are self evident. An assessment of this kind is dependent on many factors:
- the pump medium
- the number of hours of operation per year
- whether or not overhauls are to be carried out by the company’s own staff
- delivery times for spare parts from the manufacturer
- storage costs etc.
Figure 1.6.3 shows a proposal for storage of spare parts for centrifugal pumps based on the German VDMA Standard
Figure 1.6.3 Proposal for storage of spare parts for centrifugal pumps.
When purchasing and planning pump installations and their maintenance it is important that the pump supplier provide information concerning the retention of stocks of spare parts for pumps in various branches of industry. The following points can be used as the basis for a check list:
- Normal delivery times for different types of spare parts
- Length of time spare parts are stocked after the particular model of pump has gone out of production
- Spare parts to be regarded as subject to wear or to be regarded as subject to maintenance and which components are replaceable
When non-operation of the pump involves risk of damage for example the possibilities of flooding or vital cooling systems being put out of action a back-up unit with an automatic starting system must always be installed. When a number of pumps of the same size and with the same function are used, it is a rational policy to have one complete unit in reserve for switchover in the event of a breakdown or in the case of a planned overhaul. Naturally the pipe connections, electrical installations, etc. should permit really rapid switchover with the minimum of inconvenience and effort.
If overhauls and repairs are to be performed by company staff, it is also important that the instruments and tools required for the purpose should be obtained. Pump suppliers can make the necessary recommendations. The use
of unsuitable tools frequently results in more serious damage than that for which measures were to be taken.