VACUUM SYSTEM APPARATUS AND METHOD

Aspects of the present invention relate to a vacuum system. The vacuum system includes a vacuum pump; and a heat exchanger for receiving a heat transfer fluid. The heat transfer fluid comprising a gas. The heat exchanger is thermally coupled to the vacuum pump and is operable to absorb thermal energy from the vacuum pump. Aspects of the present invention also relate to a method of operating a vacuum system; and a controller for controlling operation of a vacuum system.

FIELD

The present disclosure relates to a vacuum system apparatus and method. Aspects of the invention relate to a vacuum system; a heat exchange apparatus; a method of operating a vacuum system and a controller for controlling operation of a vacuum system.

BACKGROUND

It is known to provide industrial vacuum systems with cooling blocks to maintain a target operating temperature for a vacuum pump. The target operating temperature is typically set to suit a particular industrial process. The target operating temperatures of vacuum pumps continue to increase in order to reduce process-related pump failures.

High power compression stages or active heating is required to achieve the target operating temperatures. The gas temperature in the exhaust conduit has to maintained similar to the pump outlet temperature to prevent or reduce condensation of the process gases. It is known to introduce a purge gas, such as nitrogen (N), into the vacuum pump or into an exhaust conduit of the vacuum pump to minimise condensation failures. As the process flow to the pump increases, there is an increase in the pump power while the pump operates under high load. There is a corresponding increase in the operating temperature of the vacuum pump. The vacuum pumps are equipped with cooling blocks to maintain the pump temperature during such an event. However, when the vacuum pump is operating at low loads, for example during idle operating conditions, the cooling block functions as a heat sink which absorbs thermal energy. The cooling block delays the vacuum pump reaching the target operating temperature. Thus, additional power is consumed to achieve the target operating temperature.

It is an aim of the present invention to address one or more of the disadvantages associated with the prior art.

SUMMARY

Aspects and embodiments of the invention provide a vacuum system, a method of operating a vacuum system and a controller as claimed in the appended claims.

According to a first aspect of the present invention there is provided a vacuum system comprising:

a vacuum pump; and

a heat exchanger for receiving a heat transfer fluid, the heat transfer fluid comprising a gas;

wherein the heat exchanger is thermally coupled to the vacuum pump and is operable to absorb thermal energy from the vacuum pump.

The heat transfer fluid promotes heat rejection from the vacuum pump. At least in certain embodiments, the supply of heat transfer fluid to the heat exchanger can be controlled. Thus, the transfer of thermal energy from the vacuum pump can be controlled, for example in dependence on one or more operating parameters of the vacuum pump. At least in certain embodiments, the footprint of the vacuum system may be smaller than that of prior art systems. The power consumption of the vacuum system may be reduced; and/or emissions associated with operation of the vacuum system may be reduced.

The heat exchanger may comprise an inlet and an outlet. A flow path may be defined between the inlet and the outlet. In use, the heat transfer fluid introduced through the inlet follows the flow path and is discharged through the outlet. The flow path may, for example, comprise or consist of a serpentine path or a convoluted path to increase the heat exchange surface area. The heat exchanger may have one or more internal fins for promoting heat exchange with the heat transfer fluid.

The heat exchanger may be mounted to the vacuum pump. The vacuum pump may comprise a pump housing. The heat exchanger may be thermally coupled to the pump housing. The heat exchanger may be mounted to the pump housing. A thermal coupler may be provided between the heat exchanger and the heat exchanger to promote thermal conduction.

The heat transfer fluid may comprise a purge gas for introduction into the vacuum pump.

The vacuum system may comprise at last one port. The heat exchanger may be connected to the at least one port. For example, a heat exchanger outline line may be connected to the or each port. In use, the heat transfer fluid from the heat exchanger may be introduced into the at least one port. The port may be provided in the vacuum pump to enable introduction of the heat transfer fluid into the vacuum pump. The port may, for example, be configured to introduce the heat exchange fluid into an intermediate stage of the vacuum pump. The port may, for example, comprise an inter-stage port of the vacuum pump. Alternatively, or in addition, the port may be provided in an exhaust (or final stage) of the vacuum pump to enable introduction of the heat transfer fluid into the exhaust.

The vacuum system may comprise a gas heater for heating the heat transfer fluid. The gas heater may, for example, be disposed between the heat exchanger and the port. The heat transfer fluid discharged from the heat exchanger may be supplied to the gas heater. The gas heater may perform additional heating prior to introducing the purge gas into the vacuum pump.

The vacuum system may comprise means for controlling the supply of the heat transfer fluid to the heat exchanger. The control means may comprise a pump, for example. Alternatively, the control means may comprise at least one control valve. The control valve(s) may be suitable for controlling the supply of the heat transfer fluid to the heat exchanger. The control valve(s) may, for example, comprise one or more three-way valve. Other types of valve are contemplated.

The at least one control valve may optionally control a supply rate of the heat transfer fluid. Alternatively, or in addition, a flow restrictor may be provided for controlling the supply rate. The flow restrictor may be fixed or variable.

The at least one control valve may be operable selectively to bypass the heat exchanger. The heat exchanger may, for example, be bypassed to supply the gas directly to the gas heater.

The vacuum system may comprise a valve controller for controlling operation of the at least one control valve. The valve controller may comprise at least one electronic processor having at least one input for receiving a signal indicating an operating state of the vacuum pump.

The valve controller may be configured selectively to actuate the control valve to decrease or inhibit the supply of the heat transfer fluid to the heat exchanger to reduce the absorption of thermal energy from the vacuum pump. The valve controller may be configured to control the control valve to reduce heat rejection during idle operation of the vacuum pump, for example during a start-up procedure. The heat exchanger may be configured to reduce heat rejection in dependence on a decreased load or a low load on the vacuum pump. The valve controller may be configured selectively to actuate the control valve to decrease the supply of the heat transfer fluid to the heat exchanger in dependence on the signal indicating that the vacuum pump is operating in a low load condition.

The valve controller may be configured selectively to actuate the control valve to increase the supply of the heat transfer fluid to the heat exchanger to increase the absorption of thermal energy from the vacuum pump. The valve controller may be configured to control the control valve to increase heat rejection during high load operating conditions. The heat exchanger may be configured to increase heat rejection in dependence on an increased load or a high load on the vacuum pump. The valve controller may be configured selectively to actuate the control valve to increase the supply of the heat transfer fluid to the heat exchanger in dependence on the signal indicating that the vacuum pump is operating in a high load condition.

The gas may be pre-heated before being supplied to the gas heater. The vacuum system may be configured to reduce heating performed by the gas heater while the heat exchanger is active.

The vacuum system may comprise a cooling block thermally coupled to the heat exchanger. The cooling block may be operable selectively to absorb thermal energy from the heat exchanger. The cooling block may be configured to receive a coolant. The coolant may comprise or consist of a liquid. The liquid may comprise water, for example.

The cooling block may have an inlet and an outlet for conveyance of the coolant. The liquid coolant may be introduced into the cooling block through the inlet and discharged through the outlet.

The vacuum system may comprise a cooling block controller for controlling a supply of the coolant to the cooling block. A coolant control valve may be provided to control the supply of the coolant to the cooling block. The cooling block controller may control operation of the coolant control valve. The cooling block controller may be configured to supply coolant in dependence on a determination that the temperature of the heat exchanger is greater than or equal to a predefined temperature threshold.

The heat exchanger and the cooling block may be operable independently of each other. For example, the vacuum system may be configured to activate the heat exchanger when the cooling block is inactive. The vacuum system may be configured to activate the heat exchanger and the cooling block concurrently.

According to a further aspect of the present invention there is provided a heat exchange apparatus for mounting to a vacuum pump, the heat exchange assembly comprising:

a gas heat exchanger having a first side for thermal coupling to the vacuum pump; and

a cooling block for receiving a liquid coolant, the cooling block being thermally coupled to a second side of the gas heat exchanger. The first and second sides may be opposing sides of the gas heat exchanger. In use, the gas heat exchanger is disposed between the vacuum pump and the cooling block. At least in certain embodiments, the cooling block is spaced apart from the vacuum pump. In use, the cooling block may be at least partially thermally isolated from the vacuum pump. The gas heat exchanger may be operated to promote rejection of thermal energy from the vacuum pump. The cooling block may be operated to promote rejection of thermal energy from the gas heat exchanger. The gas heat exchanger and the cooling block may be operable independently of each other. In use, one or both of the gas heat exchanger and the cooling block may be active. For example, the gas heat exchanger may operate on its own or in conjunction with the cooling block.

The gas heat exchanger may comprise a gas inlet and a gas outlet. The gas inlet and the gas outlet may be connected by an internal conduit. The internal conduit may, for example, comprise a serpentine pathway. The cooling block comprises a liquid coolant inlet and a liquid coolant outlet. The gas inlet and the gas outlet are connected by an internal conduit. The internal conduit may, for example, comprise a serpentine pathway.

According to a further aspect of the present invention there is provided a method of operating a vacuum system, the vacuum system comprising a vacuum pump and a heat exchanger for absorbing thermal energy from the vacuum pump, the heat exchanger being configured to receive a heat transfer fluid;

wherein the heat transfer fluid comprises a purge gas and the method comprises selectively supplying the heat transfer fluid from the heat exchanger to the vacuum pump or into an exhaust of the vacuum pump.

The method may comprise controlling the supply of the heat transfer fluid to the heat exchanger in dependence on one or more operating parameters of the vacuum pump.

The method may comprise supplying the heat transfer fluid to the heat exchanger in dependence on a determination that the vacuum pump has an operating temperature greater than or equal to a predetermined threshold.

The method may comprise actuating a control valve to control the supply of the heat transfer fluid to the heat exchanger.

The method may comprise selectively actuating the control valve to bypass the supply of the heat transfer fluid to the heat exchanger.

According to a further aspect of the present invention there is provided a controller for controlling operation of a vacuum system, the controller comprising at least one electronic processor and a memory, wherein a set of instructions is stored in the memory; and, when executed, the instructions cause the controller to implement the method as described herein.

DETAILED DESCRIPTION

A vacuum system1in accordance with an embodiment of the present invention is described herein with reference to the accompanying Figures.

The vacuum system1comprises a vacuum pump3. The vacuum pump3is operable to create a vacuum in a vacuum chamber (not shown). The vacuum chamber is suitable for performing an industrial process. In use, process gases are introduced into the vacuum chamber. The vacuum pump3comprises a pump housing5which supports a rotor shaft (not shown). The vacuum pump3may, for example, be used in industrial and high vacuum processes. The vacuum pump3is a multi-stage pump comprising a plurality of stages. The vacuum pump3may, for example, having five (5), six (6) or seven (7) stages. The process gases are introduced into a first one of the stages through a process gas inlet; and exhausted through from a final one of the stages through a process gas outlet.

As shown inFIG.1, the vacuum system1comprises the vacuum pump3, a heat exchanger7, a control valve9and a gas heater11. The heat exchanger7is thermally coupled to the pump housing5of the vacuum pump3. As described herein, the heat exchanger7is operative to cool the vacuum pump3. The control valve9in the present embodiment comprises a three-way valve. The control valve9controls the supply of a heat transfer fluid to the heat exchanger7. The heat transfer fluid transfers thermal energy from the heat exchanger7, thereby aiding heat rejection from the vacuum pump3and providing a cooling function. In the present embodiment, the heat exchanger comprises a gas heat exchanger and the heat transfer fluid consists of a gas. The gas is supplied from a main gas supply13. A heat transfer fluid control valve14is provided for selectively controlling the supply of gas from the main gas supply13. In the present embodiment, the heat transfer fluid is a purge gas suitable for introduction into the vacuum pump3to purge contaminants. The purge gas in the present embodiment is nitrogen (N), but it will be understood that different purge gases may be used for other industrial processes. It is not essential that the heat transfer fluid is also used as a purge gas.

A perspective view of the heat exchanger7is shown inFIG.2. The heat exchanger7comprises a body portion15, a first inlet17for introduction of the heat transfer fluid; and a first outlet19for discharging the heat transfer fluid. The heat exchanger7is thermally coupled to the pump housing5. In the present embodiment, the heat exchanger7is fastened to the pump housing5in a face-to-face arrangement. Mechanical fasteners (not shown) which locate in respective mounting apertures21formed in the body portion15. The body portion15of the heat exchanger7and the pump housing5may have complementary profiles. For example, the pump housing5may comprise a planar section for contacting a sidewall of the body portion15of the heat exchanger7. A thermal conductor, such as a thermal conductive gel, may optionally be provided at the interface between the pump housing5and the heat exchanger7. In a variant, the heat exchanger7could be integrated into the pump housing5. For example, the heat exchanger7could be formed in the pump housing5.

The vacuum system1comprises an inlet line23; an outlet line25and a bypass line27. The inlet line23connects the first inlet17of the heat exchanger7to the control valve9. The outlet line25connects the first outlet19of the heat exchanger7to the gas heater11. In use, the inlet line23supplies the heat transfer fluid from the gas supply13to the heat exchanger7; and the outlet line25conveys the heat transfer fluid from the heat exchanger7to the gas heater11. At least one internal conduit is formed in the body portion15of the heat exchanger7to establish a flow path between the first inlet17and the first outlet19. The at least one internal conduit forms a convoluted flow path for the heat transfer fluid to increase the internal heat exchange surface area of the heat exchanger7. The at least one internal conduit may, for example, define a serpentine flow path within the heat exchanger7. Alternatively, or in addition, one or more fins or projections may be provided inside the heat exchanger7to increase the internal heat exchange surface area. The heat exchanger7is composed of a thermally conductive material such as aluminium or a metal alloy. In the present embodiment, the heat exchanger7is formed using an additive manufacturing process, such as three-dimensional (3D) printing. Alternatively, or in addition, the heat exchanger7may be formed using casting and/or machining processes.

The gas heater11is provided to heat the purge gas prior to introduction into the vacuum pump3. The gas heater11may comprise an inline heater. In the present embodiment, the gas heater11is a positive temperature coefficient (PTC) heater. The heat transfer fluid discharged from the heat exchanger7is conveyed to the gas heater11through the outlet line23. As outlined above, the heat transfer fluid is a purge gas for introduction into the vacuum pump3(or another pump). This gas heater11heats the heat transfer fluid to a predetermined target temperature before mixing with the process gas. The heat transfer fluid is supplied to an inter-stage port29provided in the vacuum pump3. The inter-stage port29introduces the heat transfer fluid to an intermediate stage, or a final (exhaust) stage of the vacuum pump3. As described herein, the heat exchanger7can pre-heat the heat transfer fluid prior to introduction into the gas heater11. The pre-heating of the heat transfer fluid may reduce energy consumption by the gas heater11. Alternatively, the control valve9can be actuated to bypass the heat exchanger7and supply the heat transfer fluid directly to the gas heater11. The introduction of the heat transfer fluid into the vacuum pump3(or another pump) after heating by the gas heater11is unchanged in this variant.

The vacuum system1comprises a valve controller31for controlling operation of the control valve9. The valve controller31comprises at least one electronic processor33and a memory35. A set of computational instructions is stored in the memory35. When executed, the computational instructions cause the at least one electronic processor33to perform the method(s) described herein. The valve controller31is configured to receive one or more input signal S1from a vacuum pump controller37; and to output one or more control signal S2to the control valve9. The input signal S1is configured to provide an indication of an operating state of the vacuum pump3. The input signal S1may indicate a load of the vacuum pump3. The valve controller31may determine that the vacuum pump3is operating under a low load (for example, an idle state). The valve controller31may determine that the vacuum pump3is operating under a high load, for example when a process gas inlet valve is in an open state to supply process gases to the vacuum pump3. The valve controller31is configured to actuate the control valve9in dependence on the determined operating state of the vacuum pump3. Alternatively, or in addition, the input signal S1may indicate a load condition of the vacuum pump3. The operation of the vacuum pump3is controlled by the vacuum pump controller37in a conventional manner. It will be understood that the valve controller31and the vacuum pump controller37may be combined into a single controller. A single controller could control both the vacuum pump3and the control valve9. For example, the vacuum pump controller37could be configured also to control the control valve9in accordance with the method(s) described herein.

Thermal energy generated by operation of the vacuum pump3conducts to the heat exchanger7. The valve controller31controls the control valve9to control the supply of the heat transfer fluid to the heat exchanger7, thereby controlling cooling of the vacuum pump3and the pump housing5. The valve controller31outputs the control signal S2to the control valve9and the heat transfer fluid control valve14. The control valve9and the heat transfer fluid control valve14are actuated in dependence on the control signal S2. The valve controller31is configured to actuate the heat transfer fluid control valve14to a closed state when the input signal S1indicates that the vacuum pump3is not operating. The valve controller31is configured to actuate the heat transfer fluid control valve14to an open state when the input signal S1indicates that the vacuum pump3is operating either in a low load or a high load condition. The heat transfer fluid passes through the at last one internal conduit23(shown schematically inFIG.2) formed in the heat exchanger7. The heat transfer fluid absorbs thermal energy from the heat exchanger7and is subsequently discharged from the heat exchanger7. As described herein, the control valve9comprises a three-way valve in the present embodiment. To control operation of the heat exchanger7, the control valve9can be configured selectively to operate in the following states:(i) HEAT EXCHANGER SUPPLY—The inlet line23is placed in fluid communication with the main gas supply13such that the heat transfer fluid is supplied to the heat exchanger7. The bypass line27is closed, thereby inhibiting (or reducing) the direct supply of the heat transfer fluid to the gas heater11.(ii) HEAT EXCHANGER BYPASS—The bypass line27is placed in fluid communication with the main gas supply13such that the heat transfer fluid is supplied directly to the gas heater11. The inlet line23is closed, thereby inhibiting (or reducing) the supply of the heat transfer fluid to the heat exchanger7.

The valve controller31is configured to actuate the control valve9to the HEAT EXCHANGER BYPASS state when the input signal S1indicates that the vacuum pump3is operating under a low load. The heat transfer fluid bypasses the heat exchanger7and is supplied directly to the gas heater11. This enables the vacuum pump3to achieve a target operating temperature more quickly under idle or low load conditions as the rejection of thermal energy from the pump housing5is reduced. The valve controller31is configured to actuate the control valve9to the HEAT EXCHANGER SUPPLY state when the input signal S1indicates that the vacuum pump3is operating in a high load condition. The control valve9diverts the heat exchange fluid to the heat exchanger7at least partially to compensate for an increase in pump temperature due to the high load. The heat exchanger7is effective in maintaining or reducing the temperature of the vacuum pump3. The heat exchange fluid is pre-heated by the heat exchanger7and supplied to the gas heater11.

The operation of the vacuum system1will now be described with reference to a first block diagram100shown inFIG.3. The vacuum system1is activated (BLOCK105). The vacuum pump3is initially not operating and the valve controller31actuates (or maintains) the heat transfer fluid control valve14in a closed state BLOCK110). The supply of the heat transfer fluid to the heat exchanger7and the gas heater11is inhibited. The vacuum pump controller37activates the vacuum pump3(BLOCK115). The vacuum pump3operates in an idle, low load condition. The valve controller31actuates the transfer fluid control valve14to an open state. The valve controller31actuates the control valve9to the HEAT EXCHANGER BYPASS state (BLOCK120). The bypass line27is opened such that the heat transfer fluid bypasses the heat exchanger7. In this configuration, the heat exchanger7provides limited cooling of the vacuum pump3. The vacuum pump3reaches a target operating temperate (BLOCK125). The process gas inlet valve is actuated to an open state and process gases are supplied to the vacuum pump3. The vacuum pump controller37outputs the first control signal S1to indicate that the vacuum pump3is operating in a high load condition (BLOCK130). The valve controller31actuates the control valve9to the HEAT EXCHANGER SUPPLY state (BLOCK135). The inlet line23is opened such that the heat transfer fluid is supplied to the heat exchanger7. In this configuration, the heat exchanger7provides effective cooling of the vacuum pump3. The heat transfer fluid is pre-heated by the heat exchanger7and then supplied to the gas heater11. The gas heater11can provide controlled heating of the heat transfer fluid for introduction into the vacuum pump3and mixing with the process gases. The vacuum pump controller37closes the process gas supply valve to inhibit the supply of process gases to the vacuum pump3. The first control signal S1is output by the vacuum pump controller37to indicate that the vacuum pump3is operating in a low load condition. The vacuum pump controller37de-activates the vacuum pump3(BLOCK140). The valve controller31actuates the transfer fluid control valve14to a closed state (BLOCK143). The vacuum system1is deactivated (BLOCK150).

At least in certain embodiments, the vacuum system1can provide advantages over prior art arrangements. By bypassing the heat exchanger7, the conduction of thermal energy from the vacuum pump3(to the heat exchanger7) can be reduced. As a result, the power consumption of the vacuum pump3may be reduced in certain embodiment. In a prior art arrangement, a cooler block may be mounted to the pump housing5of the vacuum pump3. The cooler block uses a liquid coolant, typically water. At least in certain embodiments, the vacuum system1described herein may require less water for cooling of the vacuum pump3. This may also reduce the requirement to cool the heated coolant (water), thereby reducing the need for operation of a cooler for reducing the temperature of the heated coolant prior to re-circulation. At least in certain embodiments, the heat exchanger7may be smaller in size (and potentially also have a lower mass) than a cooling block, thereby reducing the footprint of the vacuum pump3. Excess heat generated by the vacuum pump3may be used to heat the purge gas. This may reduce the power consumption by the gas heater11.

The valve controller31is described herein as controlling the control valve9in dependence on the input signal S1received from the vacuum pump controller37. In a variant, the input signal S1may comprise or consist of a temperature signal indicating an operating temperature of the vacuum pump3. The temperature signal could be measured, for example by one or more temperature sensors; or could be modelled based on one or more operating parameters of the vacuum pump3.

A vacuum system1according to a further embodiment of the present invention will now be described with reference toFIG.4. The vacuum system1is a development of the above embodiment and the description herein focuses on the differences. Like reference numerals are used for like components.

The vacuum system1comprises a vacuum pump3operable to create a vacuum in a vacuum chamber for performing an industrial process. Process gases may be introduced into the vacuum chamber. The vacuum pump3comprises a rotor shaft (not shown) which is supported in a pump housing5. The vacuum system1comprises the vacuum pump3, a heat exchanger7, a control valve9and a gas heater11. The heat exchanger7, the control valve9and the gas heater11correspond to the same components in the above embodiment. The operation of these components is substantially unchanged.

The vacuum system1also comprises a cooling block39. A liquid coolant is supplied to the cooling block39to provide cooling. The cooling block39is thermally coupled to the heat exchanger7. In the present embodiment, the cooling block39is mounted to the heat exchanger7in a face-to-face arrangement. As shown inFIG.4, the cooling block39is mounted to an external face of the heat exchanger7spaced apart from the pump housing5. Thus, the heat exchanger7is disposed between the pump housing5and the cooling block39. The cooling block39may, for example, have mounting holes which align with the mounting holes21formed in the heat exchanger7. The mechanical fasteners may fasten the heat exchanger7and the cooling block39to the pump housing5. In a variant, the heat exchanger7and the cooling block39may be formed integrally.

The cooling block39comprises a second inlet41and a second outlet43. A coolant control valve45is provided for controlling the supply of the liquid coolant to the second inlet41. The coolant control valve45is actuated selectively to control the absorption of thermal energy from the heat exchanger7. The liquid coolant is discharged through the second outlet43. The coolant discharged from the second outlet43may be supplied to a chiller (not shown) for cooling and then recirculated through the cooling block39.

The vacuum system1comprises a valve controller31which is configured to control the cooling block39. In the present embodiment, the valve controller31controls operation of the coolant control valve45to control the supply of coolant to the cooling block39. As shown inFIG.4, the valve controller31outputs a pump control signal S3to control operation of the coolant control valve45. In a variant, the valve controller31may selectively open and close a control valve to control the supply of coolant to the cooling block39. The valve controller31may control operation of the coolant control valve45in dependence on an operating temperature of the vacuum pump3and/or the heat exchanger7. The operating temperature of the vacuum pump3and/or the heat exchanger7may be measured, for example by one or more temperature sensor; or may be modelled in dependence on one or more operating parameter of the vacuum pump3. The valve controller31may be configured to control the coolant control valve45to supply coolant to the cooling block in dependence on a determination that the operating temperature of the vacuum pump3and/or the heat exchanger7is greater than or equal to a predetermined temperature threshold. The cooling block39can be deployed when the workload of the vacuum pump3is such that the temperature exceeds (or is expected to) a capability of the heat exchanger7.

The operation of the vacuum system1according to the present embodiment will now be described with reference to a second block diagram200shown inFIG.6. The vacuum system1is activated (BLOCK205). The vacuum pump3is initially not operating. The valve controller31actuates (or maintains) the heat transfer fluid control valve14to a closed state (BLOCK210). The supply of the heat transfer fluid to the heat exchanger7and the gas heater11is inhibited. The supply of coolant to the cooling block39is inhibited (BLOCK215). The vacuum pump controller37activates the vacuum pump3(BLOCK220). The vacuum pump3operates in an idle, low load condition. The valve controller31actuates the heat transfer fluid control valve14to an open state and actuates the control valve9to the HEAT EXCHANGER BYPASS state (BLOCK225). The bypass line27is opened such that the heat transfer fluid bypasses the heat exchanger7. In this configuration, the heat exchanger7provides limited cooling of the vacuum pump3. The vacuum pump3reaches a target operating temperate (BLOCK230). The process gas inlet valve is actuated to an open state and process gases are supplied to the vacuum pump3. The vacuum pump3operates in a high load state (BLOCK235). The valve controller31actuates the control valve9to the HEAT EXCHANGER SUPPLY state (BLOCK240). The inlet line23is opened such that the heat transfer fluid is supplied to the heat exchanger7. The valve controller31determines that the operating temperature of the vacuum pump3is greater than a predefined operating threshold (BLOCK245). The valve controller31determines that additional cooling is appropriate for the vacuum pump3. The valve controller31activates the coolant control valve45to supply coolant to the cooling block39(BLOCK250). The valve controller31deactivates the coolant control valve45, for example when the temperature of the vacuum pump3decreases below the predefined operating threshold (BLOCK255). The vacuum pump controller37closes the process gas supply valve to inhibit the supply of process gases to the vacuum pump3. The first control signal S1is output by the vacuum pump controller37to indicate that the vacuum pump3is operating in a low load condition. The vacuum pump controller37de-activates the vacuum pump3(BLOCK260). The valve controller31actuates the control valve9to the CLOSED state (BLOCK265). The vacuum system1is deactivated (BLOCK270).

It will be appreciated that various changes and modifications can be made to the present invention without departing from the scope of the present application.