PUMP DIFFERENCES -
CRANKSHAFT TYPE PUMPS
These types of pumps are known as triplex ceramic pumps meaning they are of a crankshaft design with the crank being supported at either end with large taper roller bearings in a sturdy aluminium crankcase.
Oversized connecting rods connected to stainless steel piston rods with solid ceramic sleeve pistons all being driven by a large steel crankshaft guaranteeing a very long service life.
Solid brass pump head with externally accessible pump check valves makes servicing or repair a breeze, inlet and outlet ports on either side of the pump head mean it can be set up to the customers requirements.
8 large head bolts locate and secure the pump head in place.
This type of pump runs a regular type of engine oil such as a 20w / 50 due to the pump's low friction meaning it doesn't require a special type of oil to operate.
WOBBLE PLATE ( SWASH PLATE) TYPE PUMPS
Generally a cheaper way to manufacture pumps due to having no support bearings at all, this design features an angled plate which is driven by the motor and the pistons have swivel feet which run on this plate generating a lot of friction which turns in to heat meaning the pump requires specialised oil to operate.
Pistons are usually constructed of Stainless steel which wear by pitting causing the seals to also fail early.
Pump heads are mostly lower grade aluminium which corrodes easily with the chemicals used these days, pump head removal is required to access the pump's check valves.
The check valves are much smaller and less robust due to design of the pump.
Most of these types of pumps operate at RPM's completely unsuitable for commercial work (2800rpm upwards) and suffer a lot of cavitation problems when run from a water reservoir.