ISO 9908:1993 pdf download – Technical specifications for centrifugalpumps -Class III.
4.9 Running clearance
When estabhshing running clearances between stationary and moving parts, consideration shall be given to operating conditions arid properties of the material (such as hardness and gall resistance) used for these parts. Clearances shall be sized to prevent contact under operating conditions, and material combinations selected to minimize the risk of seizure and erosion.
4.10 Shafts and shaft sleeves
4.10.1 General
Shafts shall be of ample size and stiffness to:
a) transmit the prime mover rated power;
b) minimize unsatisfactory packing or seal performance;
c minimize wear and the risk of seizure;
ci) take due consideration of the method of starling
arid nertLa loading involved.
4.10.2 Surface roughness
Surface roughness in the gland sealing area shall be suitable for the satisfactory operation of either mechanical seal or gland packing
4.10.3 Shaft deflection
The calculated shaft deflection at the radial plane through the outer face of the stuffing box caused by radial loads exerted during operation of the pump shall not exceed 50 m, within the allowable operating range, as verified by prototype testing.
4.10.4 Diameter
The diameter of the portions of the shaft or shaft sleeves in the seal area shall be in accordance with ISO 3069 where practicable.
4.10.5 Shaft runout
Manufacture and assembly of the shaft arid sleeve, if fitted, should ensure that the runout at a radial plane through the outer face of the stuffing box is not greater than 50 im for nominal outside diameters smaller than 50 mm, not greater than 80 urn for nominal oLtside diameters 50 mm to 100 mm, and not greater than 100 m for nominal outside diameters greater than 100 mm.
4.10.6 Axial movement
Axial movement of the rotor permitted by the bearings shall not adversely affect the performance of the mechanical seal.
4.11 Bearings
4.11.1 General
Rolling bearings of standard design are normally to be used.
4.11.2 RoIling b.arlng life
Rolling bearings shall be selected and rated in accordance with ISO 76 and ISO 281; the basic rating life (L) shall be at least 10 000 h when operating within the allowable operating range
4.11.3 lubrication
The operating instructions shall incluae information on the type and amount of lubricant to be used and the frequency of applcation.
4.11.4 Bearing housing d.slgn
The bearing housing shall be designed to prevent the ingress of contaminants and the escape of the Iubdcarit under normal operating conditions.
4.12 Shaft sealing
4.12.1 General
The pump design shaft permit the use of either mechanical seal(s) or soft packing (with the exception of giandless pumps).
The seal cavity dimensions shall be in accordance with ISO 3069 except where the operating Conditions dictate otherwise.
4.122 Stuffing box
Ample sace shall be provided for repacking, including compression of packing material, without removing or dismantling any part other than gland components and guards.
The gland shall withstand forces necessary for compressing the packing materal.
4.12.3 Mechanical seals
The mechanical seal shall be suitable to withstand the given operating conditions.
Appropriate material for the seal components shall be chosen to withstand corrosion, erosion, temperature and mechanical stress, etc.
A mechanical seal shaU not be subjected to a hydrostatic test pressure exceeding the seal pressure limit.
4.13 Nameplate
Nameplates shall be securery attachea to me pump.
The minimum information required on the nameplate shall be name (or trademark) and address of the manufacturerjsupplier. identification number of the pump (for example, serial number or product number), type and size.
Further space may be provided for additional information on rate of flow, pump total head and pump speed.
4.14 Dir.ction of rotation
The direction of rotation shall be indicated by a prominently located arrow of durable construction. For portable close-coupled pumps the direction of the starttng reaction may be indicated as afternative.
4.15 CouplIngs
If the driver is not integral with the pump design, the pump shall normally be coupled to the driver by a flexible coupling.
Coupling hatves shall be effectively secured against circumferential end axial movement relative to the shafts.
If coupling components are balanced together, the correct assembly position shall be shown by permanent and visible marks.