WO2013071105A1

WO2013071105A1 - Vacuum chamber with integrated heater and circuit

Info

Publication number: WO2013071105A1
Application number: PCT/US2012/064448
Authority: WO
Inventors: John Trott; Jos LENTFERT
Original assignee: Parker-Hannifin Corporation
Priority date: 2011-11-10
Filing date: 2012-11-09
Publication date: 2013-05-16

Abstract

The present invention provides a system, apparatus and method for filtering fluid in a vacuum chamber assembly and providing uncontaminated fluid to a reservoir. A chamber includes an inlet having an inlet valve for moving a fluid into the chamber, a first outlet having an outlet valve for moving the fluid out of the chamber, and a vent line for controlling a vacuum level in the chamber. A diffuser is arranged in the chamber to dehydrate the fluid, and a moisture sensor detects a moisture level of fluid entering the inlet. When the inlet valve is open and the outlet valve is closed fluid enters the chamber through the inlet and fills the chamber until a maximum fluid setpoint is reached, at which point the inlet valve is closed and the fluid is circulated through the chamber until a moisture setpoint as determined by the moisture sensor is reached. The outlet valve then is opened and fluid is directed out through the first outlet until a minimum fluid setpoint is reached.

Description

VACUUM CHAMBER WITH INTEGRATED HEATER AND CIRCUIT

Field of Invention

The present invention relates generally to fluid dehydration, and more particularly to a vacuum chamber assembly and system for removing water from hydraulic fluid.

Background

Certain hydraulic systems include a tank or reservoir that receives and stores hydraulic fluid. These hydraulic systems often create pressures and vacuums within the tank or reservoir during use. Breather vents are typically provided in the tank to ensure that uncontaminated air is provided into the system and that the proper pressures are maintained for efficient and safe operation of the system.

For various reasons, water may find its way into the hydraulic fluid. For example, rain may leak into externally located reservoirs or seep through reservoir covers, access panels, breathers or worn seals. Additionally, condensation from air in reservoirs and other system areas can be a source for water contamination. Water can also enter the fluid system from the process side, from leaky heat exchangers or coolers, or direct ingression of process water, such as cooling water, washdown water or steam.

Water in hydraulic fluid is undesirable for a number of reasons. For example, water contamination can deplete some additives and react with others to form corrosive by-products which attack some metals. In addition, water contamination can reduce lubricant film-strength, which leaves critical surfaces vulnerable to wear and corrosion, as well as reduce filterability, increase air entrainment ability and increase the likelihood of cavitation.

Various methods exist for removing water from hydraulic fluid. One such method is vacuum dehydration, which uses purifiers to dry hydraulic fluids and lubricants by exposing them to a partial vacuum. Exemplary vacuum dehydration methods include flash distillation vacuum dehydration and mass transfer vacuum dehydration. While both processes utilize the concentration gradient between the fluid and the evacuated air to evaporate the water from the fluid, the flash distillation technology also applies heat to further boil off more water and operates at a higher vacuum. This makes flash distillation more rapid, as it removes more water from the fluid than a mass transfer device.

A problem with conventional vacuum dehydration methods is that they are relatively inefficient. More specifically, the amount of power required to remove a unit of water is high, thus increasing operation costs of such systems.

Summary of Invention

The present invention provides an apparatus, system and method for dehydrating hydraulic fluid. More particularly, hydraulic fluid is processed in a vacuum chamber so as to expose the hydraulic fluid to a partial vacuum, thereby removing water from the fluid. A heater is arranged in the vacuum chamber to heat the fluid in the chamber. By placing the heater in the chamber, the efficiency of the dehydration system is significantly increased compared to conventional systems, resulting in lower costs for removing water from hydraulic fluid.

According to one aspect of the invention, a fluid circulatory system for dehydrating a hydraulic fluid includes: a chamber including an inlet having an inlet valve for moving the fluid into the chamber, a first outlet having an outlet valve for moving the fluid out of the chamber, and a vent line for controlling a vacuum level in the chamber; a dehydration device arranged in the chamber and operative to facilitate dehydration of the fluid; a heater arranged in the chamber, the heater operative to heat the fluid to a predetermined temperature; and a moisture sensor operative to detect a moisture level of fluid entering the inlet, wherein when the inlet valve is open and the outlet valve is closed fluid enters the chamber through the inlet and fills the chamber until a maximum fluid setpoint is reached, at which point the inlet valve is closed and the fluid is circulated through the chamber until a moisture level as determined by the moisture sensor corresponds to a target moisture level, at which point the outlet valve is opened and fluid is directed out through the first outlet until a minimum fluid setpoint is reached.

In one embodiment, the dehydration device increases a surface area of the fluid that is exposed to the vacuum. In one embodiment, the dehydration device comprises a diffuser.

In one embodiment, the system includes a fluid level sensor assembly configured to determine the maximum fluid level and the minimum fluid level in the chamber.

In one embodiment, when the moisture level corresponds to the target moisture level, the vent line is opened to remove vacuum from the chamber.

In one embodiment, the chamber comprises a second outlet for recirculating the fluid through the chamber.

In one embodiment, the system includes the chamber includes a vacuum line for receiving a vacuum signal to create a vacuum in the chamber.

In one embodiment, the system includes a vacuum source coupled to the vacuum line and operative to create a vacuum in the chamber.

In one embodiment, the vacuum source comprises one of a vacuum pump or a venture.

In one embodiment, when the inlet valve is open and the outlet valve is closed the fluid is drawn into the chamber via vacuum.

In one embodiment, the system includes a fluid pump, wherein when the inlet valve and the outlet valve are closed the fluid pump recirculates the fluid between the moisture sensor, inlet, the diffusor, and the second outlet to form a closed recirculation path.

In one embodiment, when the fluid pump is recirculating the fluid, the chamber is under vacuum.

In one embodiment, the system includes a fluid pump, wherein when the inlet valve is closed and the outlet valve is open the vent line is open and the fluid pump pumps the fluid out of the chamber to the outlet valve via the first outlet.

In one embodiment, the system includes a controller operatively coupled to the moisture sensor, inlet valve and outlet valve, the controller configured to independently open and close the vent line, inlet and outlet valves based on the measured moisture level of the fluid.

According to another aspect of the invention, a vacuum device for dehydrating a fluid includes: a chamber for receiving the fluid; a dehydration device arranged in the chamber, the dehydration device operative to facilitate water removal from the fluid; and a heater arranged in the chamber, the heater operable to heat the fluid to a predetermined temperature.

In one embodiment, the device includes a fluid level sensor assembly configured to determine a maximum fluid level and a minimum fluid level in the chamber.

In one embodiment, the chamber includes: an inlet for drawing the fluid into the chamber, the inlet part of a first flow path; a first outlet for removing the fluid from the chamber, the first outlet part of a second flow path; a second outlet for recirculating the fluid through the chamber, the second outlet part of a third flow path; a vacuum line for receiving a vacuum signal; and a vent line for controlling an amount of vacuum in the chamber.

In one embodiment, the device includes a check valve arranged in the first flow path, the check valve operative to enable forward fluid flow in the first flow path through the diffusor and inhibit reverse fluid flow from the diffusor to the first flow path.

In one embodiment, the dehydration device comprises a diffusor.

In one embodiment, the device includes an inlet valve coupled to the inlet, and outlet valve coupled to the outlet.

According to another aspect of the invention, a method for dehydrating a fluid includes: moving fluid from an external source through a moisture sensor and into a vacuum chamber until the fluid fills the vacuum chamber to a predetermined level, the moisture sensor measuring an amount of water in the fluid; heating the fluid via a heating device arranged inside the chamber;

recirculating the fluid in the chamber through a dehydration device and the moisture detector until a water level in the fluid as measured by the moisture detector is below a predetermined value; and moving the fluid out of the vacuum chamber to the external source.

In one embodiment, the method includes heating the fluid in the vacuum chamber.

In one embodiment, moving the fluid into the vacuum chamber and recirculating the fluid though the vacuum chamber is performed under vacuum.

In one embodiment, moving the fluid out of the vacuum chamber is performed with the vacuum chamber vented. The foregoing and other features of the invention are hereinafter described in greater detail with reference to the accompanying drawings.

Brief Description of the Drawings

Fig. 1 illustrates an exemplary hydraulic system including a dehydration system in accordance with the invention.

Fig. 2 is a schematic diagram illustrating an exemplary vacuum chamber assembly in accordance with the invention.

Fig. 3 is a schematic diagram illustrating an exemplary heater that may be used in the vacuum chamber assembly in accordance with the invention.

Fig. 4 is a schematic diagram illustrating an exemplary dehydration system in accordance with the invention.

Fig. 5 is a schematic diagram illustrating another exemplary dehydration system in accordance with the invention.

Fig. 6 is a schematic diagram illustrating yet another exemplary dehydration system in accordance with the invention.

Detailed Description

Referring now to the drawings in detail, and initially to Fig. 1 , an exemplary hydraulic system is indicated generally by reference numeral 10. The hydraulic system 10 includes a hydraulic reservoir 12, which stores hydraulic fluid that is used to power hydraulic devices. As is known, hydraulic reservoirs hold excess hydraulic fluid to accommodate volume changes due to, for example, cylinder extension and contraction, temperature driven expansion and contraction, and leaks. As will be appreciated by one having ordinary skill in the art, the reservoir 12 may be sized to meet the requirements of the specific application.

The reservoir 12 includes a system outlet 12a, which provides the hydraulic fluid to a pump 14 for pressurization, a system inlet 12b for return of the hydraulic fluid to the reservoir, a dehydration system outlet 12c for providing hydraulic fluid to a dehydration system, and a dehydration system inlet 12d for receiving dehydrated fluid from the dehydration system. A pump 14, which is coupled to the system outlet 12a, pressurizes the hydraulic fluid as is conventional. In the exemplary hydraulic system 10, the pump 14 is a gear pump, although other types of pumps (e.g., piston pumps, vane pumps, etc.) may be used depending on the requirements of the specific application.

The pressurized fluid then is provided to control valve 16, which includes a plurality of hydraulic connections. For example, the control valve 16 can include a high pressure inlet 16a for receiving pressurized fluid from the pump 14, an outlet for returning the fluid to the reservoir 12, and first and second control ports 16c and 16d for coupling to a hydraulic device 20, e.g., a hydraulic cylinder, a hydraulic motor, etc. In the system shown in Fig. 1 , the control port 16c is coupled to a front side 20a of hydraulic cylinder 20, and control port 16d is coupled to a backside 20b of hydraulic cylinder 20. By varying the pressurized fluid between the front side 20a and back side 20b of the cylinder 20, linear motion can be achieved.

For example, the control valve 16 may be a spool (not shown) inside a cast iron or steel housing. The spool slides to different positions in the housing such that intersecting grooves and channels route the fluid based on the spool's position. Operation of the spool may be accomplished, for example, via manual operation of a lever 18 coupled to the spool, or via an automatic or

semiautomatic actuator (e.g., a motor, solenoids, etc., not shown).

In the exemplary system 10 shown in Fig. 1 , when the lever 18 is placed in a first position (e.g., to the left), the high-pressure fluid provided by the pump 14 is routed to control port 16c (which is coupled to the front side 20a of the cylinder 20), and the system inlet 12b of the reservoir 12 is coupled to the control port 16d (which is coupled to the back side 20b of the cylinder 20). In this manner, the front side 20a of hydraulic cylinder 20 will fill with pressurized fluid, while the backside 20b of hydraulic cylinder 20 (which is not under pressure) will expel fluid from the cylinder and back to the reservoir 12 via control port 16d. The net result of the process is movement of the cylinder arm 20c toward the left in Fig. 1 (i.e., the length between ends of the cylinder decreases). Conversely, when the lever 18 is placed in a second position (e.g., to the right) the pump 14 is coupled to control port 16d and the system inlet 12b is coupled to the control port 16c. This results in the back side 20b of hydraulic cylinder 20 filling with pressurized fluid via control port 16d, while the front side 20a of hydraulic cylinder 20 will expel the fluid back to the reservoir 12 via control port 16c. The net result is the cylinder arm 20c will move to the right in Fig. 1 (i.e., the length between ends of the cylinder increases).

While only a single pump, control valve and actuator are shown in Fig. 1 , it should be appreciated that there could be any number of pumps, control valves and actuators in the hydraulic system 10. Illustration of only a single pump, control valve and actuator is for sake of clarity.

Through normal use, environmental issues, maintenance, etc., the hydraulic fluid within the system 10 may become contaminated with water. To remove the water from the fluid, a dehydration system 30 is coupled to the reservoir 12. As will be described in more detail below, a portion of the hydraulic fluid in the reservoir 12 is provided to the dehydration system 30 for dehydration via the dehydration system outlet 12c, the portion of hydraulic fluid is dehydrated by the dehydration system 30, and the dehydrated portion is returned to the reservoir 12 via the dehydration system inlet 12d. Such process repeats until the water level in the hydraulic fluid reaches a desired setpoint.

Referring now to Fig. 2, an exemplary vacuum chamber assembly, which is referenced generally by the numeral 32, is illustrated. The vacuum chamber assembly 32 can be used in the dehydration system 30 in accordance with the present invention, and generally includes a housing 34 that defines a vacuum chamber 36. Within the vacuum chamber 36 is a heater 38 and a dehydration device 40. As used herein, the term dehydration device is a device that increases the surface area of the fluid that is exposed to the vacuum. Exemplary dehydration devices include a diffuser, coalesce, nozzle, fins, or the like. As will be described in more detail below, the housing 34 includes and inlet 34a for providing hydraulic fluid into the vacuum chamber 36, a first outlet 34b for returning the dehydrated fluid to the reservoir 12, a second outlet 34c for recirculating the fluid through the chamber 36, a vent line 34d for controlling the vacuum within the chamber 36, and a vacuum line 34e for receiving a vacuum signal to create a vacuum in the chamber 36. Also included in the vacuum chamber 36 is a temperature sensor 42, which measures a temperature of the fluid within the chamber 36. A first flow path 44a within the chamber includes the inlet 34a, surrounds at least a portion of the heater 38, and passes through the dehydration device 40. In one embodiment, a tubular structure surrounds the heater 38 and forms part of the first flow path. As fluid enters the chamber 36 via the first flow path 44a, the fluid passes through the tubular structure, is heated by the heater 38 and then is provided to the dehydration device 40, which removes water from the fluid. After passing through the dehydration device 40, the fluid accumulates in a bottom region of the chamber 36. A second flow path 44b in the chamber includes the inlet 34a, the heater 38 and the first outlet 34b. The second flow path 44b is utilized when the dehydrated fluid is pumped back to the reservoir. Finally, a third flow path 44c in the chamber includes the second outlet 34c, which provides a path by which the fluid is removed from the chamber and recirculated back into the chamber.

Preferably, the heater 38 is configured to prevent the generation of hot spots on a surface that contacts the fluid. Briefly referring to Fig. 3, in one embodiment the heater 38 is a finned structure formed from a core 38a having a defined inner volume with a plurality of fins 38b extending from an outer surface 38c of the core. The core and fins can be formed from a heat-conductive material, such as aluminum, copper or the like. Arranged within the core 38a is a heating element 38d, such as an electric heating element or the like, and a packing material 38e, such as sand, fibers or other granular material, occupies the volume in the core between an inner wall of the core and an outer surface of the heating element. By packing the heating element within a packing material, hot spots on a surface of the heater 38 can be minimized or even eliminated.

A check valve 46 may be arranged within the first flow path 44a prior to the dehydration device 40. As will be described in more detail below, the check valve 46 prevents a fluid flow through the dehydration device 40 when vacuum is removed from the chamber 36 (i.e., during return of the fluid to the reservoir 12).

Arranged within the chamber 36 is a fluid level sensor assembly 48 for measuring the fluid level within the chamber. The fluid level sensor assembly includes a low level sensor 48a for detecting when the fluid level is at or near a minimum level in the chamber 36, and a high level sensor 48b for detecting when the fluid level is at or near a maximum level in the chamber 36. As will be discussed in more detail below, the fluid level sensor assembly 48 is used in the sequencing of the dehydration system 30.

By heating the fluid within the vacuum chamber 36, the efficiency of the dehydration process is significantly increased compared to systems that do not use heat or systems that externally heat the fluid. Energy efficiency gains have been found to be significant, with results showing that at 50 percent power input the vacuum chamber assembly 32 provides only a 5-10% reduction in water removal relative to conventional systems operating at 100 percent power. Such reduction in power provides a significant reduction in operating cost of the dehydration system.

Turning now to Fig. 4, an exemplary dehydration system 30 in accordance with the present invention is illustrated. The system includes a vacuum chamber assembly, and in one embodiment the system 30 includes the vacuum chamber assembly 32 discussed above with respect to Fig. 2. A vacuum source 50 creates a vacuum signal, which is coupled to the vacuum line 34e of the vacuum chamber assembly 32. Further, a vent 52 having a variable opening is coupled to the vent line 34d of the vacuum chamber assembly 32. By controlling the variable opening of the vent 52 in conjunction with the vacuum provided at the vacuum line 34e, a vacuum is created in the vacuum chamber 36.

In one embodiment, the vacuum source 50 is a vacuum pump. In another embodiment, the vacuum source is a compressor and venturi system, where compressed air is expelled through a venturi coupled to the vacuum line 34e. An advantage of the compressor/venturi system is that it tends to be more reliable than a vacuum pump. However, the vacuum pump tends to be more efficient that a venturi system.

An inlet valve 54 receives fluid from the reservoir 12 for dehydration. More specifically, a first end of the inlet valve 54 is coupled to the dehydration system outlet 12c of the reservoir 12, and a second end of the inlet valve 54 is coupled to an inlet of a pump 56, which is driven by a motor (not shown), and to the second outlet 34c of the vacuum chamber assembly 32. Pump 56, for example, may be a gear pump, a piston pump, a vane pump, or any other pump that may be used to move hydraulic fluid. The output of the pump 56 is provided to a filter 58, which removes contaminants from the fluid as is conventional, and then to a moisture detector 60 which determines an amount of moisture in the fluid. The moisture detector 60 may be a conventional moisture detector that, for example, detects relative humidity. An output of the moisture detector 60 is coupled to the inlet 34a of the vacuum chamber assembly 32, while a pressure sensor 62 monitors a pressure of the fluid provided to the vacuum chamber assembly 32.

An outlet valve 64 provides the fluid back to the reservoir 12. More specifically, a first end of the outlet valve 64 is coupled to the dehydration system inlet 12d of the reservoir 12, and a second end of the outlet valve 64 is coupled to the first outlet 34b of the vacuum chamber assembly 32. In addition, a pressure relief valve 66 is coupled between the second end of the outlet valve 64 and the second end of the inlet valve 54. The pressure relief valve 64 is a safety device that detects when a pressure in the system exceeds a predetermined level, and opens to relieve the pressure.

A controller 68, such as a programmable logic controller (PLC), computer system including a processor and memory, or the like, is operatively coupled to the respective components of the system. For sake of clarity, connections to the individual components are not shown. It is to be understood, however, that the controller 68 receives pressure data from the pressure sensor 62, moisture data from the moisture sensor 60, temperature data from the temperature sensor 42, and/or fluid level data from the fluid level assembly 48. Such data may be in analog or digital form, discrete data, etc. as is conventional. In addition, the controller 68 provides control signals to the inlet and outlet valves 54 and 64 to independently open and close the respective valves, turn on and off the pump 56, turn on and off the vacuum source 50, control the vent 52, and control the heater 38.

With continued reference to Fig. 4, operation of the dehydration system 30 will now be described. Initially, the controller 68 places the vacuum source to the ON state, and changes the flow through the vent 52 (e.g., by changing the size of an orifice in the vent 52) to provide a desired vacuum level within the chamber 36. As a result, a vacuum is created in the chamber 36. In addition, the controller 68 places the outlet valve 64 in the CLOSED state, the inlet valve 54 in the OPEN state, and the pump 56 in the ON state. Due to the vacuum created in the chamber 36, the hydraulic fluid in the reservoir 12 is drawn through the inlet valve 54, the pump 56, filter 58, and through the moisture detector 60. The moisture detector 60 detects an initial reading of the moisture content within the hydraulic fluid, and provides the reading to the controller 68.

The fluid continues past the moisture detector 60 and enters the vacuum chamber assembly 32 via inlet 34a, where the fluid is heated by heater 38. The heat energy provided by the heater 38 is regulated by the controller 68 based on a temperature reading as obtained from the temperature sensor 42. Such regulation may be performed, for example, using a "proportional-integral- derivative" (PID) controller as is conventional.

The heated fluid then passes through the check valve 46 and through the dehydration device 40, where the fluid is exposed to the vacuum within the chamber 36. By exposing the hydraulic fluid to the vacuum, water within the fluid evaporates and is carried out of the chamber 36, thereby leaving the "dried" fluid behind. The dried fluid accumulates in the chamber until a high fluid level is detected by the high level switch 48b.

Upon the fluid reaching a high level in the chamber 36, a recirculation step begins. More specifically, the controller 68 places the inlet valve 54 in the CLOSED state, and places the pump in the ON state. The outlet valve remains in the CLOSED state, vacuum is maintained in the chamber 36 and heat is applied to the fluid. The pump 56 pulls the fluid from the chamber 36 via the second outlet 34, and moves the fluid back through the filter 58, moisture detector 60, heater 38 and dehydration device 40 to remove additional water from the fluid. Pressure in the system is monitored by the controller 68 via pressure sensor 62 to ensure fluid pressure is within an expected range and, if an out of range condition is present, appropriate action is taken. The

recirculation process continues until the moisture level in the fluid as detected by the moisture detector 60 reaches a predetermined target level.

In determining the target level for the moisture in the fluid, a step approach can be implemented. More specifically, each batch of fluid provided to the system 30 is dehydrated by a predetermined amount (i.e., a step), and then returned to the reservoir 12. For example, if it is desired to reduce the water content in the fluid by X percent, then each batch process may reduce the water content by X/10. More specifically, if fluid entering the dehydration system is at 100 percent saturation and the end goal is to have 1 percent saturation, the fluid is not recirculated through the chamber 36 until the 1 percent saturation target is reached. Instead, the fluid may be recirculated until it is at 90 percent saturation, and then returned to the reservoir 12. The next batch then is processed in a similar manner, and the process continues until the saturation level in the fluid reaches the 1 percent target level.

In determining the "step" for each batch, the controller 68 analyzes the moisture content in the fluid relative to a moisture curve, which approaches an asymptote, and determines the most efficient step. For example, the step may be a balance between the time it takes to heat the process fluid volume and the water removal efficiency. For optimum water removal efficiency it is preferable to stay as close to the moisture curve as possible. However, for optimum energy efficiency it is preferable to have a larger step (which results in not being as close to the curve as possible). In one embodiment, the step is programmed to be a 15% drop in relative humidity on the y axis of the moisture curve.

In order to more precisely determine the optimum step, the step can be based on the inlet temperature of the fluid, the system volume of fluid, and mode setting, where the mode setting is temporary use or continuous use. When the unit is in temporary mode the step level is disregarded the system follows the water removal curve as closely as possible.

Upon the moisture level in the fluid reaching the target value, the controller places the vacuum source in the OFF state, opens the vent 52 thereby venting the chamber 36 (i.e., vacuum is removed or at least minimized, thereby closing the check valve 46), and opens the outlet valve 64. The pump remains in the ON state, and due to the closed check valve 46 in combination with the open outlet valve 64, the fluid in the chamber 36 is pumped back into the reservoir 12.

By venting the vacuum (e.g., opening the vent 52 to minimize or remove any vacuum in the chamber 36) before discharge, the fluid can be pumped out of the chamber 36 without the pump 56 "fighting" the vacuum. This enables the pump 56 to operate as both a recirculation pump and a discharge pump.

Moreover, the size of the pump can be reduced, as the pump does not need to overcome the vacuum in the chamber. In contrast, if the vacuum remained in the chamber 36 during discharge of the fluid, the pump and motor would need to be sized not only to pump the fluid out of the chamber and back to the reservoir 12, but also to overcome the vacuum in the chamber 36.

Moving to Fig. 5, another embodiment of the dehydration system 30' in accordance with the invention is illustrated. The embodiment shown in Fig. 5 has many features in common with the embodiment shown in Fig. 4, which was discussed above. Therefore, only the differences between the two embodiments are discussed below.

Addressing first the vacuum chamber assembly 32', the check valve between the heater 38 and the dehydration device 40 in the embodiment of Fig. 4 has been removed in the embodiment of Fig. 5, and a direct connection between the heater and dehydration device 40 has been inserted in place of the check valve. In addition, the first outlet 34a in the embodiment of Fig. 4 and corresponding connection to the outlet valve 64 has been removed from the embodiment of Fig. 5. Removal of the check valve and first outlet from the vacuum chamber assembly 32 simplifies construction of the assembly and reduces costs.

Moving now to the circuit feeding fluid to the vacuum chamber assembly 32, the outlet valve 64 is arranged between the moisture detector 60 and the inlet 34a of the vacuum chamber assembly 32. More particularly, a first end of the outlet valve 64 is coupled to the moisture detector 60, a second end of the outlet valve 64 is coupled to the inlet 34a, and a third end of the outlet valve 64 is coupled to the dehydration system inlet 12d of the reservoir 12.

Operation of the outlet valve is as follows. In the CLOSED state, the first end of the outlet valve 64 is coupled to the second end of the outlet valve, and the third end of the outlet valve is isolated form the first and second end. Thus, in the CLOSED state fluid is provided to the vacuum chamber assembly 32. In the OPEN state, the first end of the outlet valve 64 is coupled to the third end of the outlet valve, and the second end of the outlet valve is isolated form the first and third end. Thus, in the OPEN state fluid is provided to the reservoir 12. Control of the embodiment shown in Fig. 5 is the same as the

embodiment shown in Fig. 4 and thus will not be discussed.

Moving now to Fig. 6, another embodiment of the dehydration system 30 in accordance with the invention is illustrated. Other than the means by which the vacuum is generated in the vacuum chamber 34, the embodiment of Fig. 6 is the same as the embodiment of Fig. 4, and control of the system is essentially the same between the respective embodiments. Therefore, only the differences between the two embodiments are discussed below.

In the embodiments shown in Figs. 3 and 4, the vacuum is created via a vacuum pump or the like. In the embodiment shown in Fig. 6, however, the vacuum is generated using venturi system. More specifically, the vacuum line 34e is connected to an oil-air separator 70, the vent line 34d is connected to a dryer 72, and a reservoir 74 may be provided to collect oil and/or water removed by the oil-air separator 70 and dryer 72. In addition, a compressor 76 provides a compressed air source that is expelled through a venturi 78, thereby creating a pressure differential. Respective ends of the dryers 70, 72 are coupled to the venturi, and the pressure differential creates a vacuum as the air is discharged from the compressor through the venture 78. As noted above, the venturi system is advantageous in that it requires less maintenance when compared to a vacuum pump system.

Although the invention has been shown and described with respect to a certain embodiment or embodiments, it is obvious that equivalent alterations and modifications will occur to others skilled in the art upon the reading and understanding of this specification and the annexed drawings. In particular regard to the various functions performed by the above described elements (components, assemblies, devices, compositions, etc.), the terms (including a reference to a "means") used to describe such elements are intended to correspond, unless otherwise indicated, to any element which performs the specified function of the described element (i.e., that is functionally equivalent), even though not structurally equivalent to the disclosed structure which performs the function in the herein illustrated exemplary embodiment or embodiments of the invention. In addition, while a particular feature of the invention may have been described above with respect to only one or more of several illustrated embodiments, such feature may be combined with one or more other features of the other embodiments, as may be desired and advantageous for any given or particular application.

Claims

Claims What is claimed is:

1 . A fluid circulatory system for dehydrating a fluid, comprising:

a chamber including an inlet having an inlet valve for moving the fluid into the chamber, a first outlet having an outlet valve for moving the fluid out of the chamber, and a vent line for controlling a vacuum level in the chamber;

a dehydration device arranged in the chamber and operative to facilitate dehydration of the fluid;

a heater arranged in the chamber, the heater operative to heat the fluid to a predetermined temperature; and

a moisture sensor operative to detect a moisture level of fluid entering the inlet,

wherein when the inlet valve is open and the outlet valve is closed fluid enters the chamber through the inlet and fills the chamber until a maximum fluid setpoint is reached, at which point the inlet valve is closed and the fluid is circulated through the chamber until a moisture level in the fluid as determined by the moisture sensor corresponds to a target moisture level, at which point the outlet valve is opened and fluid is directed out through the first outlet until a minimum fluid setpoint is reached.

2. The system according to claim 1 , wherein the dehydration device increases a surface area of the fluid that is exposed to the vacuum.

3. The system according to any one of claims 1 -2, wherein the dehydration device comprises a diffuser.

4. The system according to claims 1 -3, further comprising a fluid level sensor assembly configured to determine the maximum fluid level and the minimum fluid level in the chamber.

5. The system according to any one of claims 1 -4, wherein when the moisture level corresponds to the target moisture level, the vent line is opened to remove vacuum from the chamber.

6. The system according to any one of claims 1 -5, wherein the chamber comprises a second outlet for recirculating the fluid through the chamber.

7. The system according to any one of claims 1 -6, wherein the chamber further comprises a vacuum line for receiving a vacuum signal to create a vacuum in the chamber.

8. The system according to claim 7, further comprising a vacuum source coupled to the vacuum line and operative to create a vacuum in the chamber.

9. The system according to claim 8, wherein the vacuum source comprises one of a vacuum pump or a venturi.

10. The system according to any one of claims 1 -9, wherein when the inlet valve is open and the outlet valve is closed the fluid is drawn into the chamber via vacuum.

1 1 . The system according to any one of claims 1 -10, further comprising a fluid pump, wherein when the inlet valve and the outlet valve are closed the fluid pump recirculates the fluid between the moisture sensor, inlet, the diffusor, and the second outlet to form a closed recirculation path.

12. The system according to any one of claims 9-1 1 , wherein when the fluid pump is recirculating the fluid, the chamber is under vacuum.

13. The system according to claim 1 -12, further comprising a fluid pump, wherein when the inlet valve is closed and the outlet valve is open the vent line is open and the fluid pump pumps the fluid out of the chamber to the outlet valve via the first outlet.

14. The system according to any one of claims 1 -13, further comprising a controller operatively coupled to the moisture sensor, inlet valve and outlet valve, the controller configured to independently open and close the vent line, inlet and outlet valves based on the measured moisture level of the fluid.

15. A vacuum device for dehydrating a fluid, comprising:

a chamber for receiving the fluid;

a dehydration device arranged in the chamber, the dehydration device operative to facilitate water removal from the fluid; and

a heater arranged in the chamber, the heater operable to heat the fluid to a predetermined temperature.

16. The vacuum device according to claim 15 further comprising a fluid level sensor assembly configured to determine a maximum fluid level and a minimum fluid level in the chamber.

17. The vacuum device according to any one of claims 15-16, wherein the chamber comprises:

an inlet for drawing the fluid into the chamber, the inlet part of a first flow path;

a first outlet for removing the fluid from the chamber, the first outlet part of a second flow path;

a second outlet for recirculating the fluid through the chamber, the second outlet part of a third flow path;

a vacuum line for receiving a vacuum signal; and

a vent line for controlling an amount of vacuum in the chamber.

18. The vacuum device according to claim 17, further comprising: a check valve arranged in the first flow path, the check valve operative to enable forward fluid flow in the first flow path through the diffusor and inhibit reverse fluid flow from the diffusor to the first flow path.

19. The vacuum device according to any one of claims 15-18, wherein the dehydration device comprises a diffusor.

20. The vacuum device according to any one of claims 15-19, further comprising an inlet valve coupled to the inlet, and outlet valve coupled to the outlet.

21 . A method for dehydrating a fluid, comprising:

moving fluid from an external source through a moisture sensor and into a vacuum chamber until the fluid fills the vacuum chamber to a predetermined level, the moisture sensor measuring an amount of water in the fluid;

heating the fluid via a heating device arranged inside the chamber;

recirculating the fluid in the chamber through a dehydration device and the moisture detector until a water level in the fluid as measured by the moisture detector is below a predetermined value; and

moving the fluid out of the vacuum chamber to the external source.

22. The method according to claim 21 , further comprising heating the fluid in the vacuum chamber.

23. The method according to any one of claims 21 -22, wherein moving the fluid into the vacuum chamber and recirculating the fluid though the vacuum chamber is performed under vacuum.

24. The method according to any one of claims 21 -23, wherein moving the fluid out of the vacuum chamber is performed with the vacuum chamber vented.