Janus P30 Axial Piston Pump

Inlet Conditions

The pumps are available in 2 designs; either 2 port un-boosted or 3 port boosted configuration.

2 Port Design

Predominantly used in power pack applications where the supply water is fed to the pump from a low pressure source i.e. local tank or water mains with very low supply pressure. This design of pump can not lift water and the inlet pressure must be positive at all times. The pipe-work must be sized to ensure that even under minimum head conditions, the water pressure is still positive at the inlet. Failure to ensure this can result in premature pump failure. A simple check is to remove the pump inlet hose and measure the flow. The inlet flow rate must be 20% over the maximum delivery flow when the tank is at it’s lowest level. This ensures the inlet has positive pressures under dynamic conditions.

Unboosted

Do not place a filter between the tank and pump unless a pressure switch protecting against negative pressure is fitted. Filter all water upon entry to the tank. All supply pipe work to be a maximum diameter and minimum length.

The ports are clearly marked P (pressure) and T (tank) do not reverse or turn the shaft in the wrong direction or failure will result.

3 Port Design

When water is fed to the pump at a minimum of 2.5 bar by either a very high pressure water main, a head or column of water in excess of 25m in height or by an external boost pump, then the 3 port design unit should be incorporated. It separates the inlet water of the pump from the internal leakage water which must be piped away to a low pressure sump or drain if possible. Low casing   pressure will prolong the shaft seals life and prevent low pressure cavitation issues. The minimum case pressure and maximum inlet pressure is desired, a minimum positive inlet pressure of 2.0 bar above T pressure is required at all times.

Boosted

Boosted pumps can rotate in either direction. Inlet and outlet ports change according to shaft rotation. Maximum casing pressure 2.5 bar.

Motor Pump Assemblies

A standard range of bell housings and couplings are available for connecting the pumps to the B5 electric motor flange. See our Pick-A-Pack datasheet for further information on potential combinations. The pumps are not capable of operating with induced axial or radial loads on the output shaft; always adopt the use of a 3 part gear style coupling where possible. If the drive shaft/spigot location is within 0.05mm concentricity, direct inline drive assemblies are permissible.

 

Temperature

The units will generate full performance from 2°C to 50°C. For temperatures below freezing, an environmentally friendly antifreeze is available; ask for the Monopropylene Glycol datasheet. Operation above 50°C is possible however, the volumetric efficiency of the unit will be affected. Consult TWHC and specify the maximum operating temperature.

 

Filters

All incoming water to the pumps must be pre-filtered to a nominal rating of 10µm (25µm absolute) with a filter element rating of β10 = 75 or better. Return line filtration is advisable on closed loop systems. High pressure filtration may also be considered but as these are manufactured in stainless steel, we consider this an expensive option.

 

Fluid

Drinking water quality conforming to the EEC-directive 98/83/EC should be used as standard. Consult TWHC if you are unsure of the water quality. The standard product will operate happily on technical water i.e. distilled, RO water or demineralised. Changes may need to be made to the seal material or construction depending on the operating environment.

The pumps also operate on non-flammable fluids such as Glycol 95/5 mixtures; internal clearances must be adjusted when functioning on such fluids.

It is imperative the exact operating fluid is specified on all enquiries and orders. The standard construction will operate on sea water  however, due to the increased corrosion potential of the fluid, a more noble material construction may be required for long term   operation.