Knocking Hydraulic Pump

The N pump is unique in the world of hydraulics. Harry Ferguson was no doubt a world class genius to have come up with this system. It is unique in the fact that it has an intake valve that limits the stroke of the pump by limiting the amount of oil that can enter the pumps at any given position of the intake valve. There are four cam driven pistons in the pump. Two on each side. Each piston pump has it’s own intake and exhaust valve and these valves are spring loaded to open and close when oil is allowed to enter by the main “intake” valve. When a light load is held there is very little oil allowed to enter the valve chamber pumps. When a heavy load is held up more oil is allowed into the chambers but there is still an air gap produced in each of the pump chambers. This air causes a partial vacuum at each cycle of the pump and this is what pulls the mechanical parts apart slightly causing the metal parts to hammer against each other when they get old and begin to have excess loose motion. This normally causes no problem with the operation or safety of the pump. This will not happen when the lift is coming up or going down because this partial vacuum is not produced at these times because the intake valve is either all the way out or all the way in. The pump was designed like this so that when the touch control handle is moved to it's lowest position the intake valve closes off the flow of oil into the pump. This is done so that the lift arms will be able to come down completely with little or no load. If the pump didn't have the ability to limit the flow of the pump on the downward flow of oil out of the ram cylinder and through the exhaust valve the exhaust valve would not be able to exhaust enough oil for the lift arms to come down without a load on them and the lift arms would stay up all the time there was no load on them. The same thing is true when the lift has a very heavy load on the lift arms. Therefore the flow through the exhaust valve is very small so that the exhaust valve can only allow enough volume to exhaust to allow the lift under load to move slowly down and not let it just fall.

How in the world did the man come up with this efficient system of hydraulics when hydraulics themselves were in there infancy???? A genius! Zane

John A