Mechanical Installation
Pump Location
The pump must be sited in a well-ventilated, but frost-free location.
When pumping hot or cold liquids, take care to ensure that persons cannot accidentally come into contact with hot or cold surfaces.
For inspection and repair, allow suitable clearances for pump or motor removal.
Vertical installation
- Pumps fitted with motors up to and including 4 kW require a 0.3 m clearance above the motor.
- Pumps fitted with motors of 5.5 kW and up require at least a 1 m clearance above the motor to allow the use of lifting equipment.
Horizontal installation
- Pumps fitted with motors up to and including 4 kW require a 0.3 m clearance behind the motor.
- Pumps fitted with motors of 5.5 kW and up require a 0.3 m clearance behind the motor and at least a 1 m clearance above the motor to allow the use of lifting equipment.
- NB pumps with base frame must have the same clearance as pumps with motors from 5.5 to 200 kW.
Installation Positions
Arrows on the pump housing show the direction of flow of liquid through the pump.
The pumps can be installed with the motor/pump shaft in all positions between vertical and horizontal, but the motor must never fall below the horizontal plane.
Horizontal motors with feet must always be supported.
Fit isolating valves on either side of the pump as this makes it unnecessary to drain the system if the pump needs to be cleaned or repaired.
Foundation of NB, NBG Pump without Base Frame
Carry out the foundation/installation in accordance with the following instructions. Non-compliance may result in functional faults which will damage the pump components.
We recommend that you install the pump on a plane and rigid concrete foundation which is heavy enough to provide permanent support for the entire pump. The foundation must be capable of absorbing any vibration, normal strain or shock. As a rule of thumb, the weight of the concrete foundation must be at least 1.5 times the weight of the pump. The concrete foundation must have an absolutely level and even surface.
Place the pump on the foundation, and fasten it.
Foundation of NB, NBG Pump with Base Frame
This section applies only to 50 Hz pumps as base frames are not supplied for 60 Hz pumps.
We recommend that you install the pump on a plane and rigid concrete foundation which is heavy enough to provide permanent support for the entire pump. The foundation must be capable of absorbing any vibration, normal strain or shock. As a rule of thumb, the weight of the concrete foundation must be 1.5 times the weight of the pump.
The foundation must be 100 mm larger than the base frame on all four sides.
Pipework
Piping
When installing the pipes, make sure that the pump housing is not stressed by the pipes.
The inlet and outlet pipes must be of an adequate size, taking the pump inlet pressure into account.
Install the pipes so that air locks are avoided, especially on the inlet side of the pump.
Direct mounting in pipes
Pumps fitted with motors up to and including frame size 132 are suitable for direct mounting in supported pipes.
To ensure quiet operation, suspend the pipes from suitable pipe hangers.
Fit isolating valves on either side of the pump to avoid having to drain the system if the pump needs to be cleaned or repaired.
Make sure the pipes are adequately supported as close to the pump as possible, both on the inlet and the outlet side. The counter-flanges must lie true against the pump flanges without being stressed as stress would cause damage to the pump.
Bypass
The pump must not run against a closed valve as this will cause an increase in temperature/formation of steam in the pump which may cause damage to the pump.
If there is any danger of the pump running against a closed valve, ensure a minimum liquid flow through the pump by connecting a bypass or drain to the outlet pipe. The minimum flow rate must be at least 10 % of the maximum flow rate. The flow rate and head are stated on the pump nameplate.
Vibration Dampening
Elimination of noise and vibrations
In order to achieve optimum operation and minimum noise and vibration, consider vibration damping of the pump. Generally, always consider this for pumps with motors of 11 kW and up. Vibration damping is mandatory for motors of 90 kW and up. Smaller motor sizes, however, may also cause undesirable noise and vibration.
Noise and vibration are generated by the revolutions of the motor and pump and by the flow in pipes and fittings. The effect on the environment is subjective and depends on correct installation and the state of the rest of the system.
Elimination of noise and vibrations is best achieved by means of a concrete foundation, vibration dampers and expansion joints. See fig. 18.
Vibration dampers
To prevent the transmission of vibrations to buildings, we recommend that you isolate the pump foundation from building parts by means of vibration dampers.
The selection of the right vibration damper requires the following data:
- forces transmitted through the damper
- motor speed, taking speed control, if any, into consideration
- Required damping in % - suggested value is 70 %. The selection of vibration damper will differ from installation to installation. In certain cases, a wrong damper may increase the vibration level. Vibration dampers must therefore be sized by the supplier of the vibration dampers.
- If you install the pump on a foundation with vibration dampers, always fit expansion joints on the pump flanges. This is important to prevent the pump from "hanging" in the flanges.
Expansion Joints
Expansion joints provide these advantages:
- absorption of thermal expansion and contraction of pipes caused by variations in liquid temperature
- reduction of mechanical influences in connection with pressure surges in the pipes
- isolation of structure-borne noise in the pipes; this applies only to rubber bellows expansion joints.
Do not install expansion joints to make up for inaccuracies in the pipes, such as centre displacement or misalignment of flanges.
Fit the expansion joints at a minimum distance of 1 to 1 1/2 pipe diameters away from the pump on the inlet and the outlet side. This will prevent turbulence in the expansion joints, thus ensuring optimum inlet conditions and minimum pressure loss on the outlet side. At flow velocities greater than 5 m/s, we recommend that you fit larger expansion joints matching the pipes.
Use expansion joints with limiting rods to reduce the effects of the expansion or contraction forces on the pipes. We always recommend that you use expansion joints with limiting rods for flanges larger than DN 100.
Anchor the pipes in such a way that they do not stress the expansion joints and the pump. Follow the supplier’s instructions and pass them on to advisers or pipe installers
Due to the risk of rupture of the rubber bellows, we recommend that you use metal bellows expansion joints at temperatures above +100 °C combined with high pressure.
Measuring Instruments
Pressure gauge and mano-vacuum gauge
To ensure continuous monitoring of the operation, we recommend that you install a pressure gauge on the outlet side and a mano-vacuum gauge on the inlet side. Open the pressure gauge tappings only for test purposes. The measuring range of the gauges must be 20 % above the maximum pump pressure.
When measuring with pressure gauge on the pump flanges, note that a pressure gauge does not register dynamic pressure. On all NB, NBG pumps, the diameters of the inlet and outlet flanges are different which results in different flow velocities at the two flanges. Consequently, the pressure gauge on the outlet flange will not show the pressure stated in the technical documentation, but a value which may be up to 1.5 bar or approx. 15 m lower.
Ammeter
To check the motor load, we recommend that you connect an ammeter.