Liquid purification or separation – Flow – fluid pressure or material level – responsive – Discharge of treated material
Reexamination Certificate
1999-04-15
2001-06-26
Hruskocki, Peter A. (Department: 1724)
Liquid purification or separation
Flow, fluid pressure or material level, responsive
Discharge of treated material
C165S119000, C210S137000, C210S429000, C210S448000, C210S450000
Reexamination Certificate
active
06251265
ABSTRACT:
TECHNICAL FIELD
The present invention relates generally to automobile engines and more particularly to the filtering of coolant circulating through automobile engines to remove casting sand, rust particles, and other sludge entrained within the coolant flow. The invention further relates to regulating coolant pressure to the heater coils of an automobile during rapid acceleration to prevent heater coil blowout.
BACKGROUND OF THE INVENTION
Water cooled cast iron or cast aluminum engines are used throughout the automotive industry to power modern cars and trucks. During fabrication, the engine blocks of such engines are formed by pouring molten metal into a mold formed in casting sand. When the molten metal cools and solidifies to form the metal block, the casting sand is removed from around and through the block, which is further machined to form the finished part. The process of removing the casting sand, particularly from inside the engine coolant passageways of a cast engine block, is not trivial. Typically, the blocks are tumbled to dislodge the casting sand and their coolant passageways are thoroughly flushed with a cleaning solution.
While the cleaning and flushing process cleans most of the casting sand from the coolant passageways of an engine block, there nevertheless remains a small amount of sand that is not removed because it is trapped in crevices or partially imbedded in the walls of the passageways. This sand becomes a problem during normal operation of a vehicle in which the engine block is installed because the grains of casting sand are slowly dislodged by the circulating engine coolant and entrained in the flow of coolant through the water pump and coolant passageways of the engine. The abrasive effect of this sand tends to erode rotors and seals within the water pump and can collect at certain locations within the coolant passageways creating partial blockages and “hot spots” that can eventually destroy an engine. In addition to casting sand, other contaminates such as rust flakes and calcified minerals can become entrained in the coolant flow over time.
Another common problem related to vehicle coolant systems is the rupturing or blowout of a vehicle's heater core as a result of unusually high coolant pressures. Such pressures typically occur during extreme acceleration or other high engine revolution when the water pump is operating at high speeds. While the problem is more common in high performance high revolution engines, it nevertheless can also occur in common passenger vehicles. A heater core blowout is particularly expensive to repair because the heating system of the vehicle must be disassembled, which usually entails disassembly of the dash and other major components of the vehicle. In addition, a go heater core blowout can quickly drain a vehicle of its coolant, resulting in overheating and ruination of the vehicle's engine.
Some attempts to filter or remove casting sand and other sludge entrained within a vehicle's coolant flow have been made. For example, U.S. Pat. No. 3,773,107 of Bener discloses a sump trap located at the inlet of a vehicle's radiator to collect entrained sludge. U.S. Pat. No. 5,662,791 of Hurst et al. discloses an in-line filter connected in the return hose of the cooling system to filter entrained sludge particles from the flow. Other general purpose filters and valves are illustrated in U.S. Pat. No. 4,166,792 of Offer et al., U.S. Pat. No. 4,183,812 of Rosaen et al., U.S. Pat. No. 4,697,617 of Bourke et al., U.S. Pat. No. 4,743,365 of Noland, and U.S. Pat. No. 5,181,534 of Hashida et al. While the devices disclosed in these patents can be effective in removing or filtering entrained sludge particles from engine coolant, none of them addresses the problems caused by heater core overpressure. Furthermore, applicant is aware of no device that simultaneously removes entrained sediments from the coolant and provides pressure regulation for a heater coil under conditions of extreme coolant pressure to prevent heater core blowout.
Accordingly, there exists a need for an effective and efficient method and apparatus for removing entrained casting sand and sludge from the coolant flow within a vehicle engine while at the same time automatically regulating coolant pressure to the coils of a vehicle's heater core. It is to the provision of such a method and apparatus that the present invention is primarily directed.
SUMMARY OF THE INVENTION
Briefly described, the present invention, in one preferred embodiment thereof, comprises a combination sludge filter and pressure regulator valve or filter valve for an automotive coolant system. The filter valve comprises a cylindrical outer sleeve that carries an elongated cylindrical filter element. The filter element is capped at its upstream end by an upstream filter cap provided with a central opening communicating with the interior of the filter element and is closed at its downstream end by a downstream filter cap. The cylindrical hollow body of the filter element between the filter caps is formed by a porous filter medium. With this configuration, coolant entering the opening in the upstream filter cap moves into the interior of the filter element and passes through the filter medium to the outside of the filter element.
The cylindrical outer sleeve of the filter valve is capped at its ends by an upstream and a downstream end cap respectively, which capture the filter element within the outer sleeve. The upstream and downstream end caps are provided with coupling nipples for coupling the filter valve in line with the coolant hose supplying coolant to the heater coils from the water pump. An annular seal is provided around the periphery of the upstream filter cap of the filter element and the seal is sized for sliding movement against the interior surface of the valve body. The downstream filter cap is not sealed but, instead, coolant is free to flow around the downstream filter cap and through the coupling nipple on the downstream end cap of the filter valve. In this way, coolant entering the filter valve through the upstream end cap is confined by the annular seal to enter the interior of the filter element through the opening in the upstream filter cap. Since the downstream filter cap is closed, the coolant is then forced through the filter medium to the outside of the filter element, from where it flows around the downstream filter cap and through the coupling nipple of the downstream end cap of the filter valve. Thus, the invention provides an in line filter for removing casting sand and other sludge entrained in the coolant flow to the heater coils.
The filter element is shorter than the cylindrical outer sleeve of the filter valve. A coiled compression spring is disposed between the downstream filter cap of the filter element and the downstream end cap of the filter valve. The compression spring yieldably biases the filter element toward the upstream end of the filter valve with a force determined by the spring constant. Under normal coolant flow pressures, the compression spring is not compressed or is compressed only slightly by the force of coolant on the filter element and coolant flows freely through the filter valve and is filtered as it passes through the filter element. Thus, most of the time, the filter valve functions as an efficient in line coolant filter.
However, when the coolant pressure rises under conditions of extreme acceleration or other high rev condition to levels that could damage the heater core, the increased force on the filter element moves the filter element in a downstream direction against the bias of the compression spring thereby compressing the spring. This, in turn, causes coolant flow through the filter valve to be substantially restricted or shut off for the duration of the high pressure condition. The heater coil is thus protected from damage resulting from coolant pressure surges. When coolant pressure returns to normal, the compression spring urges the filter element back toward the upstream end of the filter valve, the
Hruskocki Peter A.
Womble Carlyle Sandridge & Rice
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