The object of these instructions is to summarise the principal points which must be observed when installing Bran+Luebbe metering pumps. They are not intended as a substitute for our operating instructions but should be handed to the design engineers so that the most common errors made in installing these metering pumps are avoided. On multiple machines we strongly advise a pipework diagram is forwarded to us for our comments and recommendations.

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Section I: Ideal Installations

Pump suction lines

1. Suction lines should be as short as possible
2. Unrestricted flow
3. Pipe diameters must not be less than the B + L recommendations
4. Filters are essential on capacities less than 100 litres/hour and desirable on large capacities.
5. Where accuracies of + or - 0.5% or better are required, level controls should be fitted to the suction vessel to maintain the liquid level as constant as possible
6. Flooded suction is desirable for normal liquids but for liquids having high viscosities, a good positive suction is essential.
   

Pump discharge lines

1. Discharge lines should be as short as possible
2. Pipe diameters must not be less than the B+L recommendation.
3. The pumps are of the positive displacement type and relief valves or bursting discs should be fitted if the pressure line can be positively shut off. The motor starters should also be fitted with overload protection to further reduce the possibility of damage to the pump.
4. Discharge pressure must be atleast 2m (W.G.) greater than the suction pressure.
5. When fitting a manifold to a multi-head unit, care must be taken to avoid one liquid interfering with another and producing an injector effect.

Section II: Alternate Arrangements

1. Recommended conditions. (Fig. 'a')
2. If the suction pressure is unavoidably higher than the discharge pressure, an auxiliary tank should be fitted at a lower level near the pump suction (Fig 'b') or alternatively, a spring loaded valve fitted in the discharge line (Fig 'c')
3. Injection into a pipeline without the pressure sustaining valve shown can produce an injector effect causing overdosage.
   (Fig. 'd')
4. A pulsation dampener or break tank fitted near to the pump suction will reduce a pulsing flow.
5. A pulsation dampener fitted immediately after the pump discharge will also reduce a pulsing flow.
   

1. Major temperature changes in the liquid being pumped will naturally affect the gravity and although the volume delivered will remain constant, the weight delivered will vary in proportion to the temperature.
2. As previously mentioned, high viscosity liquids require special attention and when handling liquids with a viscosity of 500 centipoise or more it is essential that we are given details in order to recommend a suitable pump.
3. If slurries are being handled, the pipework should be arranged so that the setting out of the slurry in the valve and pipework is kept to a minimum.
4. The "running in" of the pump is important if the capacity is smaller than 35 litres/hour. We would recommend that the pump is not calibrated until this has been done.
5. For ease of maintenance we would recommend the connections are positioned in such a manner that the pumphead may be withdrawn without having to disconnect any other pipework apart from the pumphead flanges, i.e. flanges should face front or rear of the machine.

Should the conditions of your installation not comply with the above recommendations, do not hesitate to contact the Technical Support Department who will be pleased to study the problem and advise on suitable solutions.