Apparatus for and method of filtering a fluid
AssigneeROLLS-ROYCE plc
InventorAndrew Clarke
Life of this patent
Estimating the term…
Abstract
A fuel system (10) comprises a tank (12), a pump (14), heat exchangers (16 & 18) and a filter (20) in series fluid flow relationship. A fuel metering unit (24) returns a proportion of the filtered fuel to the tank (12) and is controlled by the engine electronic control (30). The system (10) operates so that fluid is not returned to the tank (12) when a pressure differential of the order of 5 psi is detected across the fluid filter (20) and the temperature of the fluid is below 0° C. The fluid is not returned to the tank (12) for a period of time to reduce the flow of fluid passing through the heat exchangers (16 & 18). The reduced flow of fluid passing through the heat exchangers (16 & 18) is heated to a temperature sufficient to melt any solidified impurities blocking the fluid filter (20).
Claims26
A fluid filter assembly comprising a fluid tank, a pump, at least one heater and a filter in series fluid flow relationship, a temperature sensor configured and arranged to detect a temperature of the fluid, a pressure sensor configured and arranged to detect a pressure differential across the filter, means for returning a proportion of the filtered fluid to the fluid tank being provided and incorporating means to control the amount of fluid being returned to the tank, the control means operating to prevent the fluid being returned to the tank when a pressure differential is detected across the fluid filter and the temperature of the fluid is below a predetermined value.
A method of melting solidified impurities blocking a fluid filter in a fluid filter assembly, which comprises a fluid tank, a pump, at least one heater and a filter in series flow relationship, means being provided for returning a proportion of the filtered fluid to the fluid tank and which incorporates means to control the amount of the fluid passing therethrough, the method comprising the steps of, operating the control means to allow a proportion of the fluid to be returned to the fluid tank, detecting the pressure differential across the fluid filter and the temperature of the fluid, operating the control means when the pressure differential and the temperature reach a predetermined value to prevent the fluid returning to the tank, preventing the fluid returning to the tank for a predetermined period of time so that the flow of fluid passing through at least one heater is reduced, heating the reduced flow of fluid passing through at least one heater to a temperature sufficient to melt any solidified impurities in the fluid filter.
A fluid filter assembly comprising:
- a tank configured and arranged to hold a fluid;
- a pump configured and arranged to pump the fluid;
- at least one heater configured and arranged to heat the fluid;
- a filter configured and arranged to filter the fluid;
- a temperature sensor configured and arranged to detect a temperature of the fluid;
- a pressure sensor configured and arranged to detect a pressure differential across the filter;
- a conduit and metering unit configured and arranged to return a proportion of the filtered fluid to the tank;
- and
- a controller configured and arranged to control the proportion of the filtered fluid returned to the tank,
- wherein the fluid tank, the pump, the at least one heater and the filter are connected in a series fluid flow relationship, and
- wherein the controller is further configured and arranged to control the proportion of the filtered fluid returned to the tank based on the detected temperature and the detected pressure differential.
A fluid filter assembly comprising:
- a fluid tank;
- a filter in a downstream fluid flow relationship to the fluid tank;
- a temperature sensor to detect a temperature of the fluid;
- a pressure sensor to detect a pressure differential across the filter;
- a metering unit having a return path to return a proportion of the filtered fluid to the fluid tank;
- an ice blockage determining mechanism to signal when the filter is blocked with ice when both a pressure differential is detected across the fluid filter and the temperature of the fluid is below a predetermined value;
- and
- a corrective action mechanism to take a corrective action when the ice blockage determining mechanism signals that the filter is blocked with ice.
A fluid filter assembly comprising:
- a fluid tank;
- a filter in a downstream fluid flow relationship to the fluid tank;
- a temperature sensor to detect a temperature of the fluid;
- a pressure sensor to detect a pressure differential across the filter;
- a metering unit having a return path to return a proportion of the filtered fluid to the fluid tank;
- a blockage determining mechanism to determine a type of blockage of the filter, the blockage being because of ice blockage when both a pressure differential is detected across the fluid filter and the temperature of the fluid is below a predetermined value, the blockage being for reasons other than ice blockage when the pressure differential is detected and the temperature of the fluid is at a predetermined level above the predetermined value.
Dependencies are inferred from the claim text.