Аксиальная и КШМ помпа

Pros and cons about
axial & crankshaft pumps
PCH-stv-hp PCH/ Präsentationen 2012/ Axial vs crankshaft 1
Today there are a lot of controversial discussed pros and cons about
axial vs crankshaft pumps
in the market
The following overview should give you a neutral prospect in this object.
PCH-stv-hp PCH/ Präsentationen 2012/ Axial vs crankshaft 2
Claim: Crankshaft pumps have a much higher efficiency than axial pumps.
(in some cases up to 10%)
Fact: Mainly all standard crankshaft pumps have a slightly higher efficiency of
1-2 % in comparison to axial pumps.
Reason for this is higher friction force between pistons, springs, swash
plate on a axial pump.
PCH-stv-hp PCH/ Präsentationen 2012/ Axial vs crankshaft 3
Claim: Crankshaft pumps have lower vibrations (often compared with V8 motor).
Fact: The vibrations on the pump itself is exactly the same.
Main influence on the overall vibrations has the electrical motor.
Info:
Pumps with a pair number of pistons creating a higher pulsation, and
therefore more vibrations.
PCH-stv-hp PCH/ Präsentationen 2012/ Axial vs crankshaft 4
Claim: The noise level on crankshaft pumps is lower.
Fact: Both types of pumps reach similar noise levels.
Noise level on a water-cooled motor is generally lower.
Info:
Main influencing factor has the electrical motor.
4-pole versions (app. 1400 rpm) have a 5-7 % lower noise level.
PCH-stv-hp PCH/ Präsentationen 2012/ Axial vs crankshaft 5
Claim: Crankshaft pumps are easier for service/ maintenance.
Fact: Mostly axial pumps use less parts than crankshaft pumps.
BUT
The principle of a plunger pump (similar to engine) is well-know and
common worldwide.
Info:
Please consider that crankshaft pumps mainly use taper roller bearings
 Tolerance has to be adjusted.
Axial pumps adjusted itself automatically.
- Pump disassembly from the shaft could be sometimes difficult.
- Change of pistons more complex  disassembly from con-rod.
PCH-stv-hp PCH/ Präsentationen 2012/ Axial vs crankshaft 6
Claim: Crankshaft pumps are more compact than axial pumps
Fact: Up to water flow rates of appr. 1500 l/h axial pumps could be
engineered smaller, more compact and lighter.
For higher flow rates this advantage turns towards crankshaft pumps.
 Select the most cost-effective typ for different models.
PCH-stv-hp PCH/ Präsentationen 2012/ Axial vs crankshaft 7
Claim: Crankshaft pumps have a lower strain on the pistons
(transmission via con-rod).
Fact: Depending on the load the contact surface has to be adjusted on
both pump types.
Low strain = direct contact between piston + swash plate
Higher strain = additional piston shoes
PCH-stv-hp PCH/ Präsentationen 2012/ Axial vs crankshaft 8
Claim: Max. water supply temperature on axial pumps is 30° C.
Fact: - On water-cooled motors max. temperature is 60° C.
- On air-cooled motors max. temperature is 85° C (-H versions).
Info:
The most critical components by using hot water are the sealings
not the motor.
Does it make sence to supply a HDS with hot water?
PCH-stv-hp PCH/ Präsentationen 2012/ Axial vs crankshaft 9
Claim: A crankshaft pump has a higher wear resistance than axial pumps.
Fact: The wear resistance is influenced by the quality level of every single
component.
A crankshaft pump includes more parts than a axial pump.
Axial: swash plate, piston, spring.
Crankshaft: crankshaft, con-rod (2 parts) pistons (2 parts).
PCH-stv-hp PCH/ Präsentationen 2012/ Axial vs crankshaft 10