BACKGROUND
1. Field
The disclosure of the present patent application relates to liquid ring vacuum pumps, and particularly to a water-conserving, liquid ring vacuum pump system.
2. Description of the Related Art
Liquid ring vacuum pumps have an impeller with blades attached to a center hub. The blades are located within a cylindrical body and are off-set from the center. The impeller is situated between two end plates, which have inlet and outlet ports. The pump requires a liquid sealant to create a vacuum. Prior to starting, the pump is partially filled with the liquid sealant. The liquid can be water, as in water ring pumps; an oil; or a solvent, depending upon the application. These water ring vacuum pumps are heavily used in the food industry and generally have a standard ¾″ water hose from a municipal water supply hooked directly to the make-up water port of the pump. In addition to air, the output from the water ring vacuum pumps includes water, heavy contaminants (sediment), and light contaminants (foam). The water is replenished by adding water to a make-up water port on the pump. The water from the pump is commonly discharged onto the ground, or into a drain. Some municipalities require that the water be treated, before releasing it. In one example, a single 20 HP water ring vacuum pump uses 19 to 49 liters per minute, or 1,140 to 2,940 liters per hour. Many plants operate seven days a week and fifty-two weeks a year, so a single 20 HP water ring vacuum pump may use up to 25,683,840 liters of water per year. Multiply this use by the several thousand water ring vacuum pumps in service, and the amount of wasted water is staggering.
Thus, a water conserving, liquid ring vacuum pump system solving the aforementioned problems is desired.
SUMMARY
The water-conserving, liquid ring vacuum pump system receives the output from a water ring vacuum pump, removes the air and contaminants from the water to provide clean water, and returns the clean water to the make-up water port on the pump, thereby recirculating and saving most of the water that would normally be discarded. Friction in the pump also heats the water, so the system is designed to cool the water as well.
The system includes a dry compartment and a wet compartment. The dry compartment includes the electrical system components, a cooling air fan, and a cooling air distribution plenum, and houses the liquid ring vacuum pump. The wet compartment includes an open top, a left-side panel, a rear panel, a right-side panel, a front panel, and a bottom wall. Two chamber walls divide the wet compartment into three chambers. A first chamber receives water from a vacuum pump output stream after foam and air have been removed by a diffuser. A first chamber wall separates the upper portion of the first chamber from the second chamber and includes a gap to allow cold water at the lower portion of the first chamber to flow into the lower portion of the second chamber. A second chamber wall separates the lower portion of the second chamber from the lower portion of the third chamber, while allowing water to flow over the second chamber wail from the second chamber into the third chamber. The chambers form a sediment trap, such that sediment remains in the bottom of the first two chambers and cannot enter the third chamber.
The third chamber includes a thermostat extending through the front panel and a cold-water outlet connected to the water make-up port of the liquid ring vacuum pump via a solenoid valve. The thermostat opens when the water in the third chamber exceeds a predetermined limit. The third chamber also includes a float valve that opens when the level of water in the third chamber drops below a predetermined normal water level to supply cool water to the third chamber via a make-up water inlet. A water lower limit float switch opens when the water in the third chamber falls below a lower limit just above the cold-water outlet.
The cooling air system includes air-cooling tubes that extend through the third chamber. The cooling air fan has a central input for receiving cooling air from the air-cooling tubes and a fan shroud surrounding the fan for directing the cooling air to the plenum. The cooling air system further includes air-cooling tubes that extend through the first chamber and the second chamber and receive cooling air from the plenum.
The electrical system of the water-conserving, liquid ring vacuum pump system includes an AC-to-DC converter that produces a positive and a negative DC relay voltage from an AC voltage source, and also includes a first circuit breaker protecting the AC-to-DC converter. A second circuit breaker protects the vacuum pump motor, while a third circuit breaker protects the cooling air fan motor, and a fourth circuit breaker protects the solenoid of the solenoid valve. A main circuit relay connects the AC voltage source to the second, third and fourth circuit breakers. A control relay is controlled by an emergency stop switch, an on/off switch, the water lower limit float switch, and auxiliary contacts on the second, third and fourth circuit breakers. The control relay controls the main circuit relay to shut off power to the pump motor, fan motor, and solenoid should any of the circuit breakers trip, or if the water level drops below the lower limit, or if an operator depresses the emergency stop switch.
These and other features of the present subject matter will become readily apparent upon further review of the following specification.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an environmental perspective view of a water-conserving vacuum pump system, showing the housing with its front panel, left side and top covers in their closed positions.
FIG. 2 perspective view of the water-conserving vacuum pump system of FIG. 1, showing its rear panel.
FIG. 3 is a perspective view of the water-conserving vacuum pump system of FIG. 1, showing its right side with open right access panel, its open front access panel, and its top covers in their open positions, showing some of the internal components of the system.
FIG. 4 is a perspective view of a first and second chamber of a wet compartment of the water-conserving vacuum pump system of FIG. 1, as seen from above.
FIG. 5 is a perspective top view of a second and third chamber of the wet compartment of the water-serving vacuum pump system of FIG. 1, as seen from above.
FIG. 6 is a perspective view of the water-conserving vacuum pump system of FIG. 1 as seen from the right side, with a portion of its outer housing removed to show internal components of the dry compartment of the system.
FIG. 7 is a schematic diagram of the wet compartment of the water-conserving vacuum pump system of FIG. 1, showing fluid flow through the wet compartment.
FIG. 8 is a schematic electrical circuit diagram of the water-conserving vacuum pump system of FIG. 1.
Similar reference characters denote corresponding features consistently throughout the attached drawings.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The external features of the water-conserving, liquid ring vacuum pump system 100 are shown in FIGS. 1-3. The water-conserving vacuum pump system 100 includes a dry compartment 102 and a wet compartment 104. The dry compartment 102 includes a front panel 106 having a hinged electrical box access panel 108. The electrical box access panel 108 may include a panel lock 110 to prevent access by unauthorized personal. An on/off switch 139 and an emergency stop button 140 are also mounted on the access panel 108. The dry compartment 102 further includes a left-side panel 112 and a right-side panel 300 (see FIG. 3) attached to and extending at right angles to the front panel 106. The left-side panel 112 includes a vacuum port 114 for connecting the pump to vacuum-operated equipment. The right-side panel 300 includes a fan motor access panel 304 for accessing various internal components of the dry compartment 102. The fan motor access panel 304 may include a panel lock 306, to prevent access by unauthorized personal. The dry compartment 102 has an open top that is closed by a dry compartment top cover 122.
The wet compartment 104 includes a rear panel 200 (see FIG. 2) with cooling air inputs 202 to a cooling air system, second chamber cooling air outputs 204 from the cooling air system, and first chamber cooling air outputs 206 from the cooling air system. The rear panel 200 may also include a panel 208 for indicia, such as logos or tradenames. The wet compartment 104 further includes a left-side panel 116 and a right-side panel 302 attached to and extending at right angles to the rear panel 200. A left-side water drain 118 extends through the bottom of the wet compartment 104 adjacent the left-side panel 116 and includes a left-side water drain valve operated by a left side water drain valve handle 120. A right-side water drain 320 extends through the bottom of the wet compartment 104 adjacent the right-side panel 302 and includes a right-side water drain valve operated by a right-side water drain valve handle 322. The right-side panel 302 includes a make-up water inlet 326. The wet compartment 104 has an open top that is dosed by a wet compartment top cover 124.
The covers 122, 124 are attached to a ridge between the compartments 102, 104 using hinges 126, so the covers 122, 124 can be rotated upward to access the interiors of the compartments 102, 104. As best seen in FIGS. 1 and 3, cover damping and locking mechanisms are attached between the side panels 112, 116, 300, 302 and connecting lugs 127 on the side flanges of the covers 122, 124. Each cover damping and locking mechanism includes a damping cylinder 128 with a distal end rotatably connected to the connecting lug 127 and a proximate end rotatably connected to a damping cylinder anchor 129 on the corresponding side panel 112, 116, 300, 302. A cover locking bar 130 is rotatably attached at its distal end to the connecting lug 127 and includes a J-shaped slot 132. A cover locking pin 134 extends through the J-shaped slot 132 and is attached to the corresponding side panel 112, 116, 300, 302. When the covers 122, 124 are raised to their highest level and released, the cover locking pin 134 enters the curved end of the J-shaped slot 132, thereby locking the covers 122, 124 in their raised position as shown in FIG. 3. Pressing upward slightly on the covers 122, 124 releases the cover locking pin 134 from the curved end of the J-shaped slot 132, allowing the covers 122, 124 to slowly close against the damping force of the damping cylinder 128. A plurality of casters 136 may be mounted on the bottom wall of the compartments 102, 104, to allow the water conserving, liquid ring vacuum pump system 100 to be rolled into position. Alternatively, the casters 136 may be replaced by legs if portability is not required. A power cord 138 is used to connect the system 100 to an appropriate electrical power source.
The interior components of the dry compartment 102 are shown in FIGS. 3 and 6. The dry compartment 102 houses further components of the cooling air system including a fan motor 308 that drives a centrifugal fan having a fan shroud 622 (see FIG. 6). The fan pulls air through cooling tubes and into a cooling air distribution plenum 318, as described in further detail with respect to the wet compartment 104. The power cord 138 extends into an electrical junction box 310 connected to the bottom of an electrical control box 312. The fan motor 308 includes an electrical junction box 612 and a fan motor wiring harness 614 that connects the fan motor 308 to electrical circuitry described below with respect to the electrical circuit diagram 800 of FIG. 8A vacuum pump motor 314 with an electrical junction box 316 drives a liquid ring vacuum pump (not shown).
The interior components of the wet compartment 104 are shown in FIGS. 3-5. The wet compartment 104 has a front panel 400 (see FIG. 4) that divides the dry compartment 102 from the wet compartment 104. As seen in FIG. 4, an air/water output pipe 402 from the vacuum pump extends through the front panel 400 and directs the output from the vacuum pump into a diffuser 404. The functioning of the diffuser 404 is described below with respect to FIG. 7. Water from the diffuser 404 enters a first chamber 406 of the wet compartment 104. The first chamber 406 includes a plurality of air-cooling tubes 414 that extend through the front panel 400 and receive cooling air from the plenum 318. The air in the air-cooling tubes 414 is vented out of the system 100 through the first chamber cooling air outputs 206 in the rear panel 200. A first chamber wall 324 extends between the front panel 400 and the rear panel 200 and divides the upper portion of the first chamber 406 from the upper portion of the second chamber 408. The first chamber wall 324 does not extend to the bottom wall 501 (see FIG. 5) of the wet compartment 104, thereby forming a gap 410 under chamber wall 324, to allow water from the lower portion of the first chamber 406 to flow into the lower portion of the second chamber 408. The second chamber 408 includes a plurality of air-cooling tubes 416 that extend through the front panel 400 and receive cooling air from the plenum 318. The air in the air-cooling tubes 416 is vented out of the system 100 through the second chamber cooling air outputs 204 in the rear panel 200. A second chamber wall 412 extends horizontally between the front panel 400 and the rear panel 200 and vertically from the bottom wall 501 of the wet compartment 104 to a point that is just below the normal water level WL in the wet compartment 104, as described in further detail below with respect to FIG. 7. The second chamber wall 412 divides the lower portion of second chamber 408 from the lower portion of a third chamber 418, with water flowing over the top of the second chamber wall 412 from the second chamber 408 to the third chamber 418.
The details of the third chamber 418 are shown in FIG. 5, while connections to the third chamber 418 are shown in FIG. 6. The third chamber 418 includes a cold water outlet 500 that is connected to the water make-up port (not shown) of the liquid ring vacuum pump via a cold water drainpipe 600. A solenoid valve 602 in the cold water drainpipe 600 includes a solenoid 604 that is connected to the control circuitry by a solenoid valve wiring harness 606. The solenoid valve 602 closes when power to the system 100 is turned off, as described further below, to stop water flow to the liquid ring vacuum pump that may damage the liquid ring vacuum pump upon start-up. The bottom wall 501 includes a drain 502 in both the third chamber 418 and the first chamber 406 (not shown). The drain 502 in the third chamber 418 leads to the right-side water drain 320, while the drain in the first chamber 406 leads to the left-side water drain 118. A float valve 504 receives input water (preferably cool water) via the make-up water inlet 326 through the right-side panel 302. A float 506 is connected to the float valve 504 by a float shaft 508, similar to float valves found in toilet tanks. A float guide bracket 510 includes a float guide slot 512 through which the float shaft extends to thereby stabilize the float. In addition, the float guide bracket 510 may include indicia indicating the correct water level, so that the float valve 504 can be easily adjusted. A third chamber thermostat 514 extends through the front panel 400 and opens when the temperature of the water in the third chamber 418 is above a preset third chamber temperature limit, similar to thermostats in water-cooled engines. Water from the third chamber thermostat 514 is directed downward by an elbow 624 for discharge or for connection to a drainpipe that leads to a drain in the facility in which the system 100 is located.
A lower water limit sensor assembly 516 is provided to shut down the system 100, should the water level fall to a lower water level limit close to the cold water outlet 500 of the liquid ring vacuum pump. The lower water limit sensor assembly 516 includes a float 518, and a float shaft 520 connected to the float 518. The float shaft 520 extends through a float shaft bracket 521 that includes a float shaft switch 522 that opens when the water level causes the float 518 and the shaft 520 to fall. Sensor wires 524 are routed to lower water limit sensor circuitry 608 in the dry compartment 102 that is connected to the control circuitry by a lower water limit sensor wiring harness 610. The third chamber 418 includes a plurality of air-cooling tubes 526 that extend through the third chamber 418 from the cooling air inputs 202 in the rear panel 200 through the front panel 400 and provide cooling air to the central input of the centrifugal fan within the fan shroud 622. An auxiliary input extends through the front panel 400 and includes an elbow 528 to direct fluids downward into the third chamber 418. The auxiliary input receives fluids via a supply tube 620 that may include a manual valve 616 with a valve handle 618 for controlling the flow of fluids out of the supply tube 620 and into the third chamber 418. While the auxiliary input is optional, some liquid ring vacuum pumps include a pressure relief port to avoid damage to the pump should the output become blocked. The supply tube 620 may be connected to the pressure relief port of the liquid ring vacuum pump to conserve any water lost due to an over pressure condition in the pump.
The initial steps to operate the water conserving, liquid ring vacuum pump system 100 is best described with respect to FIG. 1. The system 100 is designed to be very simple to operate in order to minimize training requirements of operating personnel. After connecting the vacuum port 114 to vacuum-operated equipment, connecting the power cord 138 to an appropriate electrical power source, and connecting the make-up water inlet 326 to a source of cool water, the operator turns the on/off switch 139 to the on position, as shown in FIG. 1. Thereafter, operation of the water-conserving, liquid ring vacuum pump system 100 is automatic, as described below with respect to FIGS. 7 and 8.
Turning to FIG. 7, when the vacuum pump starts operating, its output stream enters the diffuser 404 via the air/water output pipe 402. The output stream from the vacuum pump includes mostly air, together with some water, foam and sediment. The foam F floats on top of the water in the first chamber 406 and is held in the diffuser 404 by the sides of a diffuser shroud 702. The large volume of air from the vacuum pump blows the foam F off the top of the water and upward through a vertical air/foam extraction tube 700 that extends through the top of the diffuser shroud 702. The air and foam A+F is directed by an air/foam deflector 704 into a vertical duct 708 that extends down the left-side panel 116 and is exhausted near the bottom of the left-side panel 116, or may be directed to air filtering or conditioning equipment before the air is released to the atmosphere. While some of the foam F may be blown outside of the air/foam deflector 704, it floats on top of the water in the first chamber 406 and is held in the first chamber 406 by the first chamber wall 324. The water from the diffuser 404 sinks in the first chamber 406 and is cooled by the air flowing through the plurality of air-cooling tubes 414. A first chamber thermostat 706 extends through the front panel 400 and opens when the temperature of the water in the first chamber 406 is above a preset first chamber temperature limit, similar to thermostats in water-cooled engines. As with the third chamber thermostat 514, water from the first chamber thermostat 706 is directed downward by an elbow for discharge or connection to a drainpipe that leads to a drain in the facility in which the system 100 is located.
The water exits the first chamber 406 through the gap 410 under first chamber wall 324 and enters the second chamber 408. The water then rises in the second chamber 408 and is cooled by the air flowing through the plurality of air-cooling tubes 416. Once the water in the second chamber 408 rises to the top of the second chamber wall 412 it enters the third chamber 418 and mixes with the water already in the third chamber 418. The configuration of the first chamber 406, the second chamber 408 and the water flow under the chamber wall 324 and over the second chamber wall 412 produces a sediment trap, wherein heavier sediment S collects on the bottom of the first chamber 406, and to a more limited extent on the bottom of the second chamber 408.
As the water sinks in the third chamber 418 it is cooled by the air flowing through the plurality of air-cooling tubes 526 before exiting through the cold-water outlet 500 to the water make-up port of the liquid ring vacuum pump. As the thermostats 514, 706 drain warm water from their corresponding chamber 418, 406, respectively, the water level WL in the chambers 406, 408, 418 drops. As the water level drops below the preset normal water level WL, as shown in FIG. 7, the float 506 also drops, thereby opening the float valve 504 and allowing cool water to enter the third chamber 418 via the lake-up water inlet 326. The interaction between the float valve 504 and the thermostats 514, 706 maintains the water exiting through the cold-water outlet 500 at a cold temperature to protect the vacuum pump from high temperatures.
The electrical system of the water conserving vacuum pump system 100 is shown in the system wiring diagram 800 of FIG. 8. The system includes a first circuit breaker 802 that protects an AC-to-DC converter 804 that produces a DC relay voltage, which may be any suitable DC voltage, for example 24 VDC. The first circuit breaker 802 is directly connected to a three phase (L1, L2, L3) power source and includes an auxiliary contact 828 that is wired into the DC circuit. A second circuit breaker 806 protects the vacuum pump motor 314 and includes both quick-blow and slow-blow breakers, as well as an auxiliary contact 830 that is wired into the DC circuit. A soft start for the pump motor 314 may also be included in the second circuit breaker 806. A third circuit breaker 810 protects the fan motor 308 and includes both quick-blow and slow-blow breakers, as well as an auxiliary contact 832 that is wired into the DC circuit. A fourth circuit breaker 814 protects the solenoid 604 of the solenoid valve 602 and includes an auxiliary contact 834 that is wired into the DC circuit. The second circuit breaker 806, the third circuit breaker 810, and the fourth circuit breaker 814 are connected to the three-phase (L1, L2, L3) power source via a main circuit relay 818 when its relay coil 820 is energized. The emergency stop switch 140, the on/off switch 139, the low water float switch 826, and the auxiliary contacts 828, 830, 832, 834 are all wired in series with a control relay coil 836 between the positive and negative DC voltages. The relay coil 820 of the main circuit relay 818 is directly connected to the negative DC voltage and connected to the positive DC voltage through the control relay contact 838.
If none of the circuit breakers 802, 806, 810, 814 are tripped, then all of their auxiliary contacts 828, 830, 832, 834 will be closed. If there is an adequate water level in the third chamber 418, the low water float switch 826 will be closed as well. The low water float switch 826 may be a simple switch, as shown in FIG. 5, such as the float shaft switch 522, or may be a relay contact in the lower water limit sensor circuitry 608 in FIG. 6. If the emergency stop switch 140 is also not tripped, then by turning the on/off switch 824 to the “on” position, the on/off switch 824 is closed, completing the circuit to the control relay coil 836, thereby energizing the control relay and closing its contact 838. When this contact 838 closes, the relay coil 820 of the main circuit relay 818 is energized and its contacts are closed, providing power to the vacuum pump motor 314, the fan motor 308, and the solenoid 604 of the solenoid valve 602, thereby opening the solenoid valve 602 and initiating air and water flow through the system 100. Should any of the circuit breakers 802, 806, 810, 814 trip, then the power to the vacuum pump motor 314, the fan motor 308, and the solenoid 604 of the solenoid valve 602 are shut off, thereby protecting all the components in the system 100. In addition, should the solenoid valve 602 remain open after power is removed from its solenoid 604, the soft start for the pump motor 314, will start the pump motor 314 slowly to avoid damage to the vanes of the vacuum pump from the water that entered the vacuum pump through the broken solenoid valve while the system is de-energized.
The water-conserving liquid ring vacuum pump system 100 includes simple setup and operation, as described above. In addition, the system requires very little maintenance, as no filters are employed. Once the system 100 is turned off, the wet compartment 104 is easily cleaned by opening the drain 118 in the bottom wall of the first chamber 406 to drain the first chamber 406 and the second chamber 408, and opening the drain 320 in the bottom wall of the third chamber 418 to drain the third chamber 418. The wet compartment top cover 124 may also be opened to allow flushing the sediment S and any other debris out of the chambers 406, 408, 418 and through the drains 118, 320. It should also be noted that the wet compartment top cover 124 may also be opened during operation of the system 100, and the drain 118 may also be opened during operation of the system 100 to allow flushing the sediment S and any other debris out of the chambers 406, 408. Any water that needs to be made up is supplied by the float valve 504 when the water level WL in the third chamber 418 falls below the normal water level. In addition to the ease of keeping the system 100 clean, the vast majority of external components and the internal components of the wet compartment 104 can be made of stainless steel that can be sanitized using chemicals and then easily rinsed as described above. This makes the water-conserving liquid ring vacuum pump system 100, particularly attractive for use in the food industry.
The system 100 can be used with any brand or type of water ring vacuum pump. It may also be sized to operate with different size pumps, such as 5 hp, 7.5 hp, 10 hp, 15 hp, 20 hp, 25 hp and larger. While the configuration of the system 100 remains basically the same, larger pumps require larger size systems to handle the increased water handling requirements.
It is to be understood that the water-conserving, liquid ring vacuum pump system is not limited to the specific embodiments described above but encompasses any and all embodiments within the scope of the generic language of the following claims enabled by the embodiments described herein, or otherwise shown in the drawings or described above in terms sufficient to enable one of ordinary skill in the art to make and use the claimed subject matter.
Patent Grant
12038009
