Fluid purification level control apparatuses and methods

Apparatuses and methods for level control in a fluid purification apparatus. The apparatuses and methods include a fluid purification apparatus and a level sensor that regulates operation of the fluid purification apparatus. The level sensor may further operate a bypass valve or a heater.

CROSS-REFERENCE TO RELATED APPLICATIONS

FIELD OF THE INVENTION

The present invention is directed to operation of a fluid purification system, including operational control systems and methods, safety systems and methods, temperature control systems and methods, power control systems and methods, fluid pumping systems and methods, and air filtration and fluid removal systems and methods. In particular, the fluid purification operational systems and methods are directed to systems and methods that control and provide safe operation of a fluid purification system in various environments.

BACKGROUND OF THE INVENTION

Fluid purification apparatuses, systems and methods with which the present fluid purification operational apparatuses, systems and methods may be used are disclosed in U.S. patent application Ser. Nos. 11/948,210 and 11/948,256. It is believed that certain of those fluid purification apparatuses, systems and methods would benefit from improved operational and control systems and methods.

Fluid purification apparatuses, systems and methods sometimes operate in extreme conditions or under varying circumstances. For example, certain fluid purification apparatuses and systems operate in vehicles and are subject to extreme cold temperatures. Thus, it is believed that there is a need for apparatuses, systems and methods of maintaining fluid purification operation in cold temperatures.

Other fluid purification apparatuses and systems operate in vehicles that would be better served by fluid purification apparatuses and systems that include circuitry for safe operation. Thus, it is believed that there is a need for devices, systems and methods that provide for safe operation of fluid purification apparatuses in various applications.

Pressure restricting devices are sometimes used in fluid purification apparatuses and systems. For example, in fluid purification apparatuses that separate and remove water from the fluid, pressure is frequently reduced to introduce the fluid into an evaporator chamber through which air is circulated. Such pressure restricting devices may reduce pressure at the outlet of the fluid purification apparatus to an undesirable extent. Thus, it is believed that there is a need for apparatuses, systems and methods of pumping fluid from a fluid purification apparatus and for applying energy acquired from a pressurized fluid entering a fluid purification apparatus to fluid leaving the fluid purification apparatus.

Fluid purification apparatuses, systems and methods also sometimes operate in systems using fluid storage tanks, such as hydraulic fluid tanks, and those fluid storage tanks are sometimes vented to the atmosphere. Accordingly, it is believed that there is a need for improved devices, systems and methods for treating atmospheric gases entering or leaving such a fluid storage tank.

SUMMARY OF THE INVENTION

The present invention is directed to systems, methods and apparatuses for purifying fluids. In accordance with one embodiment of the present fluid purification invention, there is provided a fluid purification apparatus, having a filter chamber, an evaporator chamber, a bypass valve, and a level sensor. The evaporation chamber is positioned adjacent the filter chamber, and has a cavity to receive fluid. The bypass valve has a first port coupled to one of the fluid purification apparatus filter chamber and the evaporator chamber, a second port for coupling to a fluid inlet line to the fluid purification apparatus, and a third port for coupling to a fluid outlet line from the fluid purification apparatus. The level sensor is disposed in the evaporator chamber cavity and coupled to actuate the bypass valve so as to position the bypass valve to prevent fluid flow through the evaporator chamber when the level of fluid in the evaporator chamber is not appropriate for operation of the evaporator chamber and to position the bypass valve for flow through the evaporator chamber when the level of fluid in the evaporator chamber is appropriate for operation of the evaporator chamber.

In another embodiment, a fluid purification apparatus includes a filter chamber, an evaporator chamber positioned adjacent the filter chamber, the evaporator chamber having a cavity to receive fluid, a pre-heater disposed on one of the filter chamber, the evaporator chamber, and a fluid inlet line conducting fluid to the fluid purification apparatus, and a level sensor disposed in the evaporator chamber cavity and coupled to energize the pre-heater when the level of fluid in the evaporator chamber is not appropriate for operation of the evaporator chamber and de-energize the pre-heater when the level of fluid in the evaporator chamber is appropriate for operation of the evaporator chamber.

In yet another embodiment, a method of preventing an evaporator chamber of a fluid purification apparatus from flooding with fluid is provided. The method includes sensing a level of a fluid in the evaporator chamber and actuating at least one of a pre-heater and a bypass valve if the level of the fluid in the evaporator chamber is above a desired level.

The present filtration apparatuses and methods provide advantages that may include improved fluid flow from a pressure reducing filtration apparatus in a pressurized fluid system.

Accordingly, the present invention provides solutions to the shortcomings of prior filtration apparatuses, systems, and methods. Those of ordinary skill in fluid purification will readily appreciate that those details described above and other details, features, and advantages of the present invention will become further apparent in the following detailed description of the preferred embodiments of the invention.

DETAILED DESCRIPTION OF THE INVENTION

Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. It is to be understood that the figures and descriptions of the present invention included herein illustrate and describe elements that are of particular relevance to the present invention, while eliminating, for purposes of clarity, other elements found in typical systems with which fluid filtration apparatuses, systems, and methods are employed.

Any reference in the specification to “one embodiment” or “an embodiment” means that a particular feature, structure or characteristic described in connection with the embodiment is included in at least one embodiment of the invention. The appearances of phrases such as “in one embodiment” in various places in the specification are not necessarily all referring to the same embodiment. References to “or” are furthermore intended as inclusive so “or” may indicate one or another of the ored terms or more than one ored term.

FIG. 1illustrates a cross-sectional view of an embodiment of a fluid purification apparatus100. The fluid purification apparatus100includes a filter chamber102, an evaporator chamber104, and a filter base105.

The filter chamber102includes a filter cavity110and a filter canister112. A filter or filter media156may be placed in the filter cavity, for example, by unscrewing the filter canister112from the base105, placing the filter media156in the filter canister112, and screwing the filter canister112back in place on the base105. The filter chamber102ofFIG. 1further includes a perforated tube114, having perforations115. The perforated tube114is situated to pass through a central cylindrical opening in the filter media156, such that fluid may flow into the filter chamber102, through the filter media156, into the perforated tube114and pass from the perforated tube114into the evaporator chamber104through an inner-chamber opening111. In one embodiment, the filter chamber102is a particulate filter chamber and functions to remove particulates from the fluid.

The evaporator chamber104includes a heater wiring inlet134, a heater130, an evaporation tube132, an evaporator gas inlet129, and an evaporator gas outlet126. A level sensor210, such as a float switch or other level sensor, and a temperature sensor214, such as a high temperature switch or other temperature sensor, may be disposed in a cavity103of the evaporator chamber104or positioned near the evaporator chamber104.

In the embodiment illustrated inFIG. 1, the evaporation tube132is fitted around the heater130and fluid passes from the filter chamber102into the evaporator chamber104through a fluid heating channel136formed between the heater130and an inner surface138of the evaporation tube132. The heated fluid flows out from the evaporator end147of the evaporation tube132after it passes through the fluid heating channel136. The heated fluid then passes over an outer surface140of the evaporation tube132and into the evaporation chamber104where certain volatiles of the heated fluid, such as water and uncombusted fuel, turn to a gas and are vented from the evaporator chamber104through the evaporator gas outlet126.

The evaporation tube132may be in contact with the divider116and may furthermore be attached to the divider116or formed with the divider116. The evaporation tube132may also be shaped with a conically shaped outer surface140that is pinched141near where the evaporation tube132meets the divider116. Fluid passing out of the fluid heating channel136may flow along the outer surface140of the evaporation tube132into a fluid reservoir152in the evaporator chamber104.

The base105includes the divider116that at least partially separates the filter chamber102from the evaporator chamber104. The base105may also include a circular wall118that extends from the divider116to at least partially enclose the evaporator chamber104. An evaporator chamber cap120may be attached to the base105to cover and provide access to the evaporator chamber104. The evaporator chamber cap120may be attached to the base105as desired and may, for example, be attached by way of screws extending through holes119in the evaporator chamber cap120and threaded into threaded holes121formed in the circular wall118.

A threaded circular portion122may also extend from the divider116portion of the base105, opposite the circular wall118, for attachment of the filter canister112.

In the embodiment illustrated inFIG. 1, a high temperature switch214is located on the base105of the fluid purification apparatus100. The high temperature switch214may alternately be located in the evaporator chamber104or elsewhere so as to sense the temperature of the fluid in the evaporator chamber104or the temperature in the vicinity of the evaporator chamber104. The high temperature switch214may be wired directly to the heater130power to de-energize the heater130when the temperature sensed by the high temperature switch214rises above the set point of the high temperature switch214. Alternately, any type of temperature sensor coupled to a controller or relay to control operation of the heater130may comprise or be included with the high temperature switch214.

Also in the embodiment illustrated inFIG. 1, a pre-heater204is wrapped around the base105or the filter canister112to warm the fluid in cold conditions. The pre-heater204may alternately or in addition be located so as to warm fluid prior to the fluid entering the fluid purification apparatus100.

The fluid purification apparatus100ofFIG. 1includes an inlet106leading to the filter chamber102and an outlet108leading from the evaporator chamber104. A pump206, a bypass valve208, and a pressure sensor212are shown adjacent to the fluid purification apparatus100near the inlet106and outlet108. One or more of those components206,208, and212may alternately be incorporated into the fluid purification apparatus100or installed in a fluid inlet line146or an fluid outlet line148.

The fluid purification apparatus100may be used in various applications including filtration of lubricants in engines of various types and in pressurized fluid applications such as hydraulic fluid system. Oil, hydraulic fluid, or another fluid may pass through the filter chamber102and the evaporator chamber104in series and in either order or may pass through the filter chamber102or the evaporator chamber104individually or in parallel.

FIG. 2illustrates a control circuit200for an embodiment of a fluid purification apparatus control system. The control circuit200shows the evaporator chamber heater130, the pre-heater204, the pump206, and the bypass valve208controlled by the level sensor210, the pressure sensor212, the temperature switch214, a pump relay216, an evaporator relay218, and a filter heater relay220.

In the embodiment ofFIG. 2, power is provided to the control circuit200when the system to which the fluid purification apparatus100is coupled is in operation. For example, if the fluid purification system is coupled to a vehicle started by a key, power that is energized when the key is turned to the on position may also power the control circuit200. Alternately, the control circuit200may be energized by power from a desired circuit of the system to which the fluid purification apparatus100is coupled or through a sensor, such as a system pressure sensor213, which may be a pressure switch or sensor/controller arrangement that indicates the fluid is under pressure and, from that, the system using the fluid is in operation.

Where the control circuit200is energized by a system pressure sensor213, that system pressure sensor213may be located anywhere pressure is applied to the fluid under normal system operation, such as for example, in a fluid line near a system fluid pump (not shown) or near the inlet106of the fluid purification apparatus100.

In one embodiment, a fluid purification apparatus or system includes a fluid purification apparatus, such as the fluid purification apparatus100illustrated inFIG. 1, and an electrical circuit, such as the control circuit200ofFIG. 2. In such an embodiment, it may be desirable to energize the control circuit200only when a system served by the fluid purification apparatus100is in operation. For example, when the fluid purification apparatus100is operating on oil in an engine, it may be desirable to operate the fluid purification apparatus100only when the engine is running. Alternately, when the fluid purification apparatus100is serving a hydraulic fluid system, it may be desirable to operate the fluid purification apparatus100only when the hydraulic fluid system is operating. To accomplish fluid purification apparatus100operation only when the system served by the fluid purification apparatus100is operating, system power that is on only when the system served by the fluid purification apparatus100is operating may be used to power the fluid purification apparatus100. Alternately, a sensor that senses operation of the system served by the fluid purification apparatus100may be used to energize the fluid purification apparatus100through its control circuit200.

In an embodiment, the system pressure sensor213is used to sense operation of the system served by the fluid purification apparatus100and energize and de-energize the fluid purification apparatus100through its control circuit200. The system pressure sensor213in the embodiment illustrated inFIG. 1is disposed to sense pressure of fluid adjacent the inlet106of the fluid purification apparatus100and is coupled, by wiring for example, to de-energize the control circuit200when pressure of the fluid is below a desired level and to energize the control circuit200when pressure of the fluid is above the desired level. The system pressure sensor213may have a switch to control operation of the control circuit200or may be of the sensor controller type and may operate one or more relays, such as relays216,218, and220where appropriate. The system pressure sensor213may furthermore operate using hysteresis and may have a fixed or adjustable set point.

In the embodiment ofFIG. 2, the heater130warms fluid in an evaporator chamber of a fluid purification apparatus, such as the evaporator chamber104of the fluid purification apparatus100illustrated inFIG. 1. The heater130warms the fluid so as to cause volatiles such as water in the fluid to evaporate so that, once separated, the volatiles may be removed from the fluid. If overheating occurs, however, the fluid may be damaged or degraded. Therefore, the temperature switch214is incorporated into the control system circuit200ofFIG. 2to de-energize the heater130if the temperature in the evaporator chamber104exceeds the set point of the temperature switch214.

In an embodiment, a bi-metal temperature controller, such as a thermostatic temperature controller, is used as the temperature switch214to de-energize the heater130if the fluid becomes too warm. The temperature controller type temperature switch214may have a temperature sensitive element, such as the bi-metal element, placed near the heated fluid and may have a contact that controls operation of the heater130directly or through a relay such as the evaporator relay218shown inFIG. 2. In an embodiment where the temperature switch214includes an electrical contact rated for the voltage and current powering the heater130, the contact may be actuated by the temperature sensitive element dependent on the temperature of the element and wired in series with the heater130. In an embodiment, the temperature switch214includes a set point adjustment to adjust the temperature at which the contact opens and closes. In another embodiment, the temperature controller type temperature switch214has a fixed set point at which the contact opens and closes.

The temperature switch214may operate using hysteresis such that the temperature switch214contact opens at one temperature and closes at a lower temperature. For example, in an embodiment, the temperature switch214contact opens when the temperature exceeds 980 Celsius and closes when the temperature drops back below 950 Celsius.

The element of the temperature switch214may be placed in direct contact with the fluid, for example in the evaporator chamber104. Alternately, the element of the temperature switch214may be placed proximate to the fluid, such as by use of a well (not shown), or by gluing or otherwise securing the temperature switch214adjacent the fluid purification apparatus100in a position that is indicative of the temperature of the fluid. The element may furthermore be incorporated into the temperature switch214or may be attached thereto rigidly or flexibly.

It may be desirable, in some embodiments, to have fluid flowing through a fluid purification system, such as the fluid purification apparatus100ofFIG. 1, when an evaporator heater, such as the heater130ofFIG. 1, is energized. An indication that fluid is flowing through the fluid purification apparatus100may be sensed in various ways, including use of a flow sensor or switch in fluid communication with the fluid flowing through the fluid purification system. alternately, a pressure sensor or switch in fluid communication with the fluid flowing through the fluid purification system may be used to indicate fluid is flowing through the fluid purification apparatus100. In the embodiment illustrated inFIG. 2, a pressure sensor212, which may be a pressure switch or another device, is used to sense fluid flow through the fluid purification apparatus100. The pressure sensor212may be located at the inlet106of the fluid purification apparatus100, at the outlet108of the fluid purification apparatus100, inside the fluid purification apparatus100, or otherwise in fluid communication with fluid flowing through the fluid purification apparatus100. The pressure sensor212may be set such that a contact in the pressure sensor212is open when fluid pressure is below a set point, which may be a desired level, and the contact is closed when fluid pressure is above the set point. In that way, the heater130is de-energized when the pressure sensor212contact is open, and the heater130is energized when the pressure sensor212contact is closed.

Either pressure sensor212or213may operate using hysteresis such that the pressure sensor212or213contact opens at one pressure and closes at a slightly different pressure. For example, in an embodiment, the contact of one of the pressure sensors212or213closes when the pressure exceeds 5 psi and opens when the pressure drops back below 4.5 psi.

In an embodiment illustrated inFIGS. 1 and 2, the pressure sensor212or other pressure sensor controller arrangement is disposed in fluid communication with fluid flowing through the filter chamber102and the evaporator chamber104. The pressure sensor212is in that fluid communication such that the pressure sensor senses the pressure of the fluid at some location within or adjacent to the filter chamber102or evaporator chamber104, such as in the inlet106of the fluid purification apparatus100. For example, in an embodiment as seen inFIG. 1, the pressure sensor212senses pressure in the inlet106of the fluid purification apparatus100, where the fluid flows from the inlet106, through the filter chamber102, through the evaporator chamber104, and out of the fluid purification apparatus100at the outlet108. That pressure sensor212is wired to the heater130through the filter heater relay220to energize the heater130when the fluid pressure at the inlet106is above a desired level and de-energize the heater130when the fluid pressure at the inlet is below the desired level. It may be noted that other devices, which may be referred to as safety devices, such as the temperature switch214, may be wired with the pressure sensor212to prevent operation of the heater130when operating conditions are not appropriate for operation of the heater130. Such operating conditions may include low flow or high temperature conditions, and/or other undesirable operating conditions.

In one embodiment, the pressure sensor is further wired to de-energize all electrical components of the fluid purification apparatus. The pressure sensor may de-energize all the electrical components when fluid is not fluid is not flowing through the fluid purification apparatus100.

As may be seen in the embodiment ofFIG. 2, the pressure sensor212and temperature switch214may be wired in series to energize the evaporator relay218when unit operational power is applied, the pressure is above the set point of the pressure sensor212, and the temperature is lower than the set point of the temperature switch214. When the evaporator relay218is energized, a contact on the evaporator relay218is closed and the heater130is energized. Thus, the heater130in this embodiment is energized when the unit is powered on, the temperature in or near the evaporator chamber104is below a temperature whereby the fluid may be damaged or degraded, and fluid is flowing through the fluid purification apparatus100.

The level sensor210, such as a float switch or other level sensor/controller, may be situated in the evaporator chamber104, as illustrated inFIG. 1. The level sensor210may be actuated to permit fluid flow into the evaporator chamber104when fluid level in the evaporator chamber104is appropriate for operation. For example, in an embodiment, when the fluid level is at or below a high level limit, the level sensor210may be actuated to permit fluid flow through the evaporator chamber104. Alternately, the level sensor may actuate the bypass valve208when the fluid level in the evaporator chamber is not appropriate for operation of the evaporator chamber104. For example, in an embodiment, it may not be appropriate to operate the evaporator chamber104when the fluid level in the evaporator chamber104rises above the high level limit of the level sensor210and, thus, the level sensor210may actuate the bypass valve208to bypass fluid flow around the evaporator chamber104.

In an embodiment of a large scale hydraulic fluid application, the level sensor210may permit flow into the evaporator chamber104when the fluid level in the evaporator chamber104is not more than half full and stop fluid flow into the evaporator chamber104when the fluid level in the evaporator chamber104is more than half full.

It has been discovered that when the fluid temperature is particularly low, for example, when hydraulic fluid is less than 25° Celsius, the fluid tends not to flow out of the evaporator chamber104well and, therefore, to accumulate in the evaporator chamber104. In the embodiment shown inFIG. 2, actuation of the level sensor210when the fluid level is below the high limit level closes an electrical contact associated with the level sensor210, thereby energizing the filter heater relay220using power supplied only when the system using the fluid is in operation. The filter heater relay220, in turn, controls operation of the pre-heater204and the bypass valve208.

The pre-heater204may be used to warm fluid being purified before the fluid enters the evaporator chamber104. In the embodiments shown inFIGS. 1 and 2, the pre-heater204includes a wrappable heating element such as a flexible heat tape type heater for wrapping around an object. Such a flexible heat tape type heater may be wrapped around the filter canister112, the inlet line leading to the filter chamber102, or elsewhere as desired. Alternately, another type of heater may be provided to warm the fluid before it enters the evaporator chamber104.

When the fluid level in the evaporator chamber rises above the level that actuates the level sensor210, the pre-heater204is energized to warm fluid in the filter chamber102. It should be noted that the pre-heater204may alternately be placed on the evaporation chamber104, the fluid inlet line146, or elsewhere to heat the fluid at any desired location.

An embodiment of the fluid purification apparatus100includes a filter chamber102and an evaporator chamber104positioned adjacent the filter chamber102. The evaporator chamber104further includes a cavity103to receive fluid in which the level sensor210is disposed. The pre-heater204is disposed on the filter chamber102, the evaporator chamber104, or the fluid inlet line146conducting fluid to the fluid purification apparatus100. The level sensor210is disposed in the evaporator chamber cavity103and coupled to energize the pre-heater204when the level of fluid in the evaporator chamber104is not appropriate for operation of the evaporator chamber104and de-energize the pre-heater204when the level of fluid in the evaporator chamber104is appropriate for operation of the evaporator chamber104. In one embodiment, the fluid level in the evaporator chamber104is appropriate for operation of the evaporator chamber104, and the level sensor210will therefore energize the pre-heater204, when the fluid level is above a predetermined level.

The bypass valve208may be located in the fluid outlet line148as shown inFIG. 1or in the fluid inlet line146as desired. The bypass valve208may have three ports, a common port241, a normally open port242, and a normally closed port243. The bypass valve208may furthermore be normally open to the fluid purification apparatus100in its de-energized state or normally open to the fluid inlet line146in its de-energized state, as desired for failsafe operation or another reason.

The bypass valve208depicted inFIGS. 1 and 2is open to the fluid inlet line146when de-energized so that fluid flows from the fluid inlet line146to the fluid outlet line148directly. The bypass valve208depicted inFIGS. 1 and 2is open to the fluid purification apparatus100when energized so that fluid flows from the fluid inlet line146through the fluid purification apparatus100and then to the fluid outlet line148. The bypass valve208is energized by the filter heater relay220when the fluid system being served by the fluid purification apparatus100is operating and when the level sensor210senses a fluid level in the evaporator chamber104below the high limit level.

Other bypass arrangements are also possible, including a bypass valve208that receives fluid from the filter chamber102and bypasses the evaporator chamber104, directing fluid from the filter chamber102directly into the system, rather than from the filter chamber102into the evaporator chamber104and then into the system. In the embodiment illustrated inFIG. 2, the fluid is furthermore pumped into the system by the pump206regardless of whether the fluid passes through the bypass valve208, although embodiments where the pump206is de-energized and the bypass valve208bypasses the pump206as well are also contemplated.

In an embodiment, a fluid purification apparatus100includes a bypass valve208having a first port243coupled to one of the filter chamber102and the evaporator chamber104, a second port242for coupling to the fluid inlet line146, and a third port241for coupling to a fluid outlet line148. That fluid purification apparatus100also includes a level sensor210disposed in the evaporator chamber104cavity103and coupled to actuate the bypass valve208so as to position the bypass valve208to prevent fluid flow through the evaporator chamber104when the level of fluid in the evaporator chamber104is not appropriate for operation of the evaporator chamber104and to position the bypass valve208for flow through the evaporator chamber104when the level of fluid in the evaporator chamber104is appropriate for operation of the evaporator chamber104.

The bypass valve208may be actuated electrically, pneumatically, or as desired. The bypass valve208may be a solenoid type valve that moves to two distinct positions or may be modulated to permit fluid flow to be mixed from two different sources or diverted to two different destinations.

The ports of the bypass valve208may be arranged as desired. For example, in one embodiment, the first port243of the bypass valve208is the common port and is coupled to the fluid inlet line146of the fluid purification apparatus100. In another embodiment, the first port243of the bypass valve208is the common port and is coupled to the fluid outlet line148of the fluid purification apparatus100.

The bypass valve208may bypass fluid flow so that there is no fluid flowing through either the evaporator chamber104or the filter chamber102of the fluid purification apparatus100when the fluid level in the evaporator chamber104is not appropriate for operation of the evaporator chamber104. The bypass valve208may further conduct fluid flow from the fluid inlet line146to the fluid outlet line148when the fluid level in the evaporator chamber104is not appropriate for operation of the evaporator chamber104. Conversely, the bypass valve208may conduct fluid flow from the fluid inlet line146, through both chambers102and104of the fluid purification apparatus100and then to the fluid outlet line148when the fluid level in the evaporator chamber104is appropriate for operation of the evaporator chamber104.

In embodiments, the bypass valve208conducts fluid flow from the filter chamber102to the fluid outlet line148when the fluid level in the evaporator chamber104is not appropriate for operation of the evaporator chamber104. In embodiments, the bypass valve208conducts fluid flow from the filter chamber102through the evaporator chamber104and then to the fluid outlet line148when the fluid level in the evaporator chamber104is appropriate for operation of the evaporator chamber104.

A method of preventing an evaporator chamber from flooding with fluid is also contemplated. An embodiment of the method includes sensing a level of a fluid in the evaporator chamber104and actuating at least one of a pre-heater204and a bypass valve208if the level of the fluid in the evaporator chamber104is above a desired level.

A method of controlling the pressure of fluid in a fluid purification apparatus100is also contemplated. An embodiment of the method includes sensing the pressure of the fluid, such as with the pressure sensor212, de-energizing the heater130disposed in the filter chamber102of the fluid purification apparatus100when the pressure of the fluid is below a desired level and energizing the heater130when the pressure of the fluid is above the desired level. In embodiments of that method, the pressure of the fluid may be sensed in the filter chamber102or in the inlet106, which is in fluid communication with the filter chamber102. The method may further include de-energizing one or more electrical components of the fluid purification apparatus100, such as all the electrical components, when no fluid is flowing through the fluid purification apparatus100. The method may further include increasing the temperature of the fluid in the evaporator chamber104of the fluid purification apparatus100when the temperature of the fluid in the evaporator chamber104is lower than a set point and possibly also when the pressure of the fluid in the filter chamber102is above the desired pressure level.

The pump206may be a fluid return pump in one embodiment as illustrated inFIGS. 1 and 2, and may be used to pressurize the fluid leaving the fluid purification apparatus100. The pump206is energized in the control circuit200ofFIG. 2when the fluid system is energized to maintain flow in the fluid system.

In certain filtration apparatuses, pressurizing fluid leaving the filtration apparatus may be unnecessary. For example, where the fluid purification apparatus100is situated above the system into which the fluid is being discharged, the fluid may flow from the fluid purification apparatus100into the fluid system by way of gravity feed. In other embodiments, however, it may be desirable to increase fluid pressure leaving the fluid purification apparatus100when, for example, fluid flow through the fluid purification apparatus100is restricted.

In the embodiment illustrated inFIG. 1, a pump206is used to propel fluid from the fluid purification apparatus100. The pump206may, for example, be an electrically powered centrifugal impeller pump. In certain embodiments, an intake pump (not shown) may be used to impel fluid into the fluid purification apparatus100. The intake pump may also be electrically powered centrifugal impeller pump, for example, or may be a pulse pump or other desired type of pump.

FIG. 2illustrates an embodiment in which the pump206is energized when the system power is turned on. In certain embodiments, such as the one shown inFIG. 2, a relay, such as the pump relay216, may be used to provide power to the pump206.

FIG. 3illustrates a top cross-sectional view of an embodiment of a fluid driven pump300andFIG. 4illustrates a side cross-sectional view of the fluid driven pump300ofFIG. 3. The fluid driven pump300may be mounted such that fluid entering the fluid purification apparatus100at or near the inlet106is propelled through a fluid driven rotating inlet device310and fluid leaving the fluid purification apparatus100is propelled by an outlet impeller320coupled to the fluid driven rotating inlet device310.

The fluid driven pump300ofFIGS. 3 and 4is provided to pressurize fluid leaving the fluid purification apparatus100using pressure from the fluid entering the fluid purification apparatus100. The fluid driven pump300includes a fluid driven rotating inlet device310in fluid communication with the inlet106of the fluid purification apparatus100and an outlet impeller320in fluid communication with the outlet108of the fluid purification apparatus100. The outlet impeller320is driven by the fluid driven rotating inlet device310such that the pressure of the fluid entering the fluid purification apparatus100is applied to fluid leaving the fluid purification apparatus100, thereby pumping the fluid out of the fluid purification apparatus100.

The fluid driven pump300ofFIGS. 3 and 4includes a housing311, the fluid driven rotating inlet device310which may include a pair of intermeshing inlet gears312and314, and the output impeller320which may include a pair of intermeshing outlet gears322and324. The pair of intermeshing inlet gears312and314are situated in fluid communication with the inlet106of the fluid purification apparatus100and the pair of intermeshing outlet gears322and324are situated in fluid communication with the outlet108of the fluid purification apparatus100. The outlet gears322and324are driven by the inlet gears312and314, thereby using the pressure of the fluid entering the fluid purification apparatus100to pump the fluid out of the fluid purification apparatus100.

In that embodiment, pressurized fluid entering the fluid purification apparatus100is directed through an inlet channel316in which teeth of the first inlet gear312and the second inlet gear314are meshed. Thus, the inlet gears312and314are driven or rotated by the pressure of the pressurized fluid entering the fluid purification apparatus100.

The first outlet gear322may be situated on a common shaft330with the first inlet gear312and the second outlet gear324may be situated on a common shaft332with the second inlet gear314. In that way, the outlet gears322and324are driven by the inlet gears312and314. The inlet106may furthermore be axially aligned with the outlet108to permit the inlet gears312and314to be stacked on the outlet gears322and324for ease of coupling of the gears by common shafts330and332. Because the outlet gears322and324are located at the outlet108of the fluid purification apparatus100, the outlet gears322and324, in turn, pump fluid out of the fluid purification apparatus100.

The first outlet gear322may be coupled to the first inlet gear312or the second outlet gear324may be coupled to the second inlet gear314by a mechanical connection other than the common shaft330or332where the common shaft330or332is undesirable.

Alternate embodiments where an inlet gear is driven by pressurized fluid entering the fluid purification apparatus100and where the inlet gear drives an outlet gear or impeller to pressurize fluid leaving the fluid purification apparatus100are further contemplated. For example, in an embodiment, a single gear may be driven by the pressurized fluid or a single gear or impeller may be driven by the inlet gear.

FIG. 5illustrates an embodiment of a hydraulic tank arrangement400for use in connection with the fluid purification apparatus100illustrated inFIG. 1. Hydraulic systems frequently incorporate a hydraulic tank402to hold excess hydraulic fluid not currently in use in the hydraulic system404. Typically, hydraulic fluid is drawn from the hydraulic tank402by a hydraulic system404when the hydraulic system404requires additional fluid and excess hydraulic fluid is returned to the hydraulic tank402when not in use in the hydraulic system404. The hydraulic tank402includes a breather406to permit air to enter the hydraulic tank402to fill space left empty when hydraulic fluid is removed from the hydraulic tank402and to permit air to escape from the hydraulic tank402when it is displaced by hydraulic fluid returning to the hydraulic tank402. It is believed, however, that air carries undesirable particles and materials into the hydraulic tank402each time air enters the hydraulic tank402. Accordingly, a filter is provided at the breather406of the hydraulic tank402ofFIG. 5.

In the embodiment depicted inFIG. 5, the filter is a desiccant type filter420that dries air entering the hydraulic tank402by removing water from that air. Any of the various types of desiccant filters known may be used in this application, including multiple cartridge desiccant dryers and self-drying desiccant filters. It has been discovered that hydraulic fluid damages certain types of commercially available desiccant material and it is recognized that only the air entering the hydraulic tank402need be dried to protect the hydraulic fluid in the hydraulic tank402. Therefore, a system of check valves has been devised to direct air leaving the hydraulic tank402directly to the atmosphere and to direct air entering the hydraulic tank through the desiccant filter420.

The check valve system includes a tee410with a first branch412coupled to the breather406of the hydraulic tank402, a second branch414coupled to a desiccant filter420, and a third branch416venting to the atmosphere. A first check valve422is coupled between the second branch414of the tee410and the desiccant filter420such that the first check valve422permits air flow from the desiccant filter420to the hydraulic tank402. A second check valve424is coupled to the third branch416of the tee410such that the second check valve424permits air flow from the hydraulic tank402to the atmosphere. In that way, air is drawn into the hydraulic tank402through the desiccant filter420, thereby drying air entering the hydraulic tank402, and air is discharged from the hydraulic tank402directly to the atmosphere, thereby preventing air discharged from the hydraulic tank402from contacting the desiccant filter420.

Numerous specific details have been set forth to provide a thorough understanding of the embodiments. It will be understood, however, that the embodiments may be practiced without these specific details. In other instances, well-known operations, components and circuits have not been described in detail so as not to obscure the embodiments. It can be appreciated that the specific structural and functional details are representative and do not necessarily limit the scope of the embodiments. Thus, while certain features of the embodiments have been illustrated as described above, many modifications, substitutions, changes and equivalents will now occur to those skilled in the art. It is therefore to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of the embodiments.