Pump
A pump including a plurality of spaced apart generally mutually parallel plates, which are mounted for rotation in a housing about an axis which extends generally normal to the plates, to effect pumping of a fluid, wherein the separation of the plates varies depending on the temperature of fluid within the housing.
1 . A pump including a plurality of spaced apart generally mutually parallel plates, which are mounted for rotation in a housing about an axis which extends generally normal to the plates to effect pumping of a fluid, wherein the separation of the plates varies depending on the temperature of fluid within the housing.
2 . A pump according to claim 1 wherein the separation of the plates decreases with increasing temperature.
3 . A pump according to claim 2 wherein the pump further includes a plurality of resilient biasing elements, a resilient biasing element being located between at least two parts of adjacent plates, and an actuator part which bears on the plates and pushes the plates closer together as the temperature of the actuator part increases.
4 . A pump according to claim 3 wherein the actuator part includes a bimetallic element.
5 . A pump according to claim 3 wherein the actuator part includes a fluid filled cylinder and piston.
6 . A lubricating system for an engine, the lubricating system including a pump for pumping liquid lubricant around the engine, the pump including a plurality of spaced apart generally mutually parallel plates, which are mounted for rotation in a housing about an axis which extends generally normal to the plates to effect pumping of the lubricant, wherein the separation of the plates decreases with increasing lubricant temperature.
7 . A lubricating system for an engine, the lubricating system including a main pump and an auxiliary pump both for pumping liquid lubricant around the engine, the auxiliary pump including a plurality of spaced apart generally mutually parallel plates, which are mounted for rotation in a housing about an axis which extends generally normal to the plates, to effect pumping of the lubricant, wherein the separation of the plates decreases with increasing lubricant temperature.
8 . A lubricating system according to claim 7 wherein the auxiliary pump is configured such that when the lubricant is relatively cold, the separation of the plates is greater than necessary to achieve optimum pumping efficiency, whereas as the temperature of the lubricant approaches an optimum operating temperature, the separation of the plates is at or around the separation necessary to achieve optimum pumping efficiency.
9 . A lubricating system according to claim 7 wherein the auxiliary pump is configured adapted such that the plate separation is as close to the plate separation necessary for optimum pumping efficiency over a range of lubricant temperatures.
10 . A method of operating a lubricating system for an engine, the lubricating system including a main pump and an auxiliary pump both for pumping liquid lubricant around the engine, the auxiliary pump including a plurality of spaced apart generally mutually parallel plates, which are mounted for rotation in a housing about an axis which extends generally normal to the plates, to effect pumping of the lubricant, wherein the separation of the plates decreases with increasing lubricant temperature, the method including the steps of operating the auxiliary pump to pump lubricant around the engine prior to engine start up, operating the main pump during normal engine operation, and ceasing operation of the auxiliary pump after the engine has reached a predetermined operating temperature.
11 . A method of operating a lubrication system according to claim 10 wherein the method further includes the steps of ceasing operation of the main pump and recommencing operation of the auxiliary pump on engine shut down.