There are a number of important advantages to take into consideration when choosing between a traditional triplex plunger pump and a Danfoss Axial Piston Pump, which are as follows:

Weight & Space

The weight/space ratio between a conventioanl plunger pump and a Danfoss APP pump both giving 30m³/h is approx 10:1, i.e. for an APP pump weighing 100kg a corresponding plunger pump will weigh approximately 1000kg, it may also require a gearbox and bedplate which will add additional weight and increase the area the pumping system occupies.

Danfoss APP pumps are direct coupled to the electric motor, thus there is no need for a gearbox or intermediate drive other than a conventional coupling, the overall width of the pump and motor unit will be governed by the motor, and the overall length will be approximately 1.5 times the motor length, this results in a compact arrangement and uses a smaller space envelope than a reciprocating pump system.

Space and weight are important considerations in the design of marine and offshore installations; for an offshore installation the cost per square metre of production area can be as high as $10,000 and so space must be used economically and any weight reductions allow savings to be made on the structural elements of the installation.

Lubrication

Plunger pumps have oil lubrication which needs to be changed at defined intervals in order to maintain the pump drive components, if the pump has a gearbox this will also have an oil lubrication system which requires regular maintenance.  The weight of the lubricants on larger systems will probably exceeed 100kg which is the total weight of an APP30 series pump.

Danfoss APP pumps are lubricated by the fluid that they are pumping, censequently there is no downtime or costs to change lubricants and dispose of spent lubricants.

Service Intervals

Danfoss pumps are guaranteed to have a life of 8000 hours between service intervals.

Fluid Pulsation

Triplex plunger pumps have 3 pistons, this results in a pulsation ripple of +/- 20% and thus the need for a pulsation dampener.  Pulsation dampeners are considered to be a hazard as they contain a high pressure gas charge which requires a routine check of the charge pressure and recharging.

Pulsation dampers are required to meed the PED regulations and spare parts and service is not a routine matter.

Danfoss APP pumps have 9 pistons (on the larger models) and produce a low pulsation pressure variation, typically only +/-1.5% and so do not need a pulsation dampener.