Abstract:
A vacuum drainage system operable to remove waste from a source. The system includes an accumulator in fluid communication with the source and a substantially vertical riser having a first portion in fluid communication with the accumulator and a second portion downstream of the first portion and in fluid communication with a vacuum source. A first valve is disposed between the first portion and the second portion. The first valve is selectively operable to provide fluid communication between the first portion and the vacuum source. An air inlet is disposed a distance downstream of the first valve and is selectively operable to provide fluid communication between the outside atmosphere and the second portion.

Description:
BACKGROUND 
   The present invention relates to a system and method for draining waste in a plumbing system. More particularly, the present invention relates to a system and method for draining waste in a plumbing system using a vacuum system. 
   Various types of drainage systems are used to direct waste from a source, or a plurality of sources, to a common collection point. For example, gravity feed systems are commonly used in residential and commercial buildings to direct waste to the desired collection point. In a gravity feed system, gravity provides the motive force to move the waste from the source(s) to the collection point. Because gravity is the main motive force, the pipes between the source(s) and the collection point must slope down toward the collection point to maintain the desired flow. However, as the pipes of a gravity system become worn, corroded, roughened, or clogged, gravity alone is sometimes insufficient to move the waste. The requirement that the pipes slope also requires careful planing prior to, and during the construction of a building to assure that the pipes are properly located. This extensive pre-planning makes the addition of pipes or new sources to a completed building difficult. 
   Vacuum drainage systems offer an alternative to gravity systems. Vacuum systems use a combination of gravity and vacuum to draw waste from the source, or sources, to a collection point. Because the main motive force is vacuum (pressure) rather than gravity, the orientation of the pipes is not significant to the operation of the unit. However, vacuum drainage systems are limited in the height to which they can lift waste and are susceptible to staling during operation. 
   SUMMARY 
   The present invention provides a vacuum drainage system operable to remove waste from a source. The system includes an accumulator in fluid communication with the source and a substantially vertical riser having a first portion in fluid communication with the accumulator and a second portion downstream of the first portion and in fluid communication with a vacuum source. A first valve is disposed between the first portion and the second portion. The first valve is selectively operable to provide fluid communication between the first portion and the vacuum source. An air inlet is disposed a distance downstream of the first valve and is selectively operable to provide fluid communication between the outside atmosphere and the second portion. 
   The invention also provides a vacuum drainage system comprising a source of waste and an accumulator in fluid communication with the source and positioned below the source to receive the waste. A vacuum source is operable to provide a vacuum region. The invention also includes a riser having a first portion in fluid communication with the accumulator and a second portion in fluid communication with the vacuum region. A sensor is operable to measure a waste level within the accumulator and an air inlet is operable in response to the waste level within the accumulator to provide fluid communication between the outside atmosphere and the second portion. A first valve is disposed between the first portion and the second portion. The first valve is movable between a first configuration and a second configuration. The first configuration inhibits fluid communication between the first portion and the second portion and the second configuration allows fluid communication between the first portion and the second portion. 
   The invention also provides a method of transferring waste using a vacuum drainage system. The vacuum drainage system includes an accumulator that receives waste from a source and a riser having a first portion in fluid communication with the accumulator and a second portion in fluid communication with a vacuum source. The method comprises positioning a valve between the first portion and the second portion and providing a selective air flow path between the atmosphere and the second portion. The method also includes sensing a waste level within the accumulator and opening the valve when the waste level exceeds a first predetermined value. The method further includes opening the air flow path to admit air into the second portion of the riser. 
   In yet another aspect, the invention provides a vacuum drainage system including a vacuum source operable to provide a vacuum region and an accumulator operable to receive a quantity of waste from at least one source. A first riser portion is in fluid communication with the accumulator and a last riser portion is in fluid communication with the vacuum region. An intermediate riser portion is disposed between the first riser portion and the last riser portion and a first valve interconnects the first riser portion and the intermediate riser portion. The first valve is selectively operable to provide fluid communication between the first riser portion and the intermediate riser portion. A first air inlet is selectively operable to provide fluid communication between the outside atmosphere and the intermediate riser portion and a second air inlet is selectively operable to provide fluid communication between the outside atmosphere and the last riser portion. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The description particularly refers to the accompanying figures in which: 
       FIG. 1  is a diagrammatic view of a portion of a vacuum drainage system embodying the present invention and including a source and vacuum collection tank; 
       FIG. 2  is a diagrammatic view of a portion of the vacuum drainage system including an aeration system; 
       FIG. 3  is a diagrammatic view of a portion of the vacuum drainage system including another aeration system with adjustable aeration timing; and 
       FIG. 4  is a diagrammatic view of a portion of a vacuum drainage system including multiple aeration stages; 
       FIG. 5  is a diagrammatic view of a portion of another vacuum drainage system including multiple aeration stages. 
   

   Before any embodiments of the invention are explained, it is to be understood that the invention is not limited in its application to the details of construction and the arrangements of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of “including,” “comprising,” or “having” and variations thereof is meant to encompass the items listed thereafter and equivalence thereof as well as additional items. The terms “connected,” “coupled,” and “mounted” and variations thereof are used broadly and encompass direct and indirect connections, couplings, and mountings. In addition, the terms “connected” and “coupled” and variations thereof are not restricted to physical or mechanical connections or couplings. 
   DETAILED DESCRIPTION 
   With reference to  FIG. 1 , a portion of a vacuum drainage system  10  is illustrated. The system  10  includes a waste source in the form of a sink  15 , a collection tank  20 , a vacuum pump  25 , and a plurality of pipes  30  and fixtures  35  (such as swing check valves, elbows, unions, tees, and the like). It should be noted that while a single sink  15  is illustrated, the vacuum drainage system  10  is capable of draining waste from several sources. In addition, there is no requirement that sinks alone be the source of waste as other sources (e.g., commodes, urinals, waste tubs, wash machines, dishwashers and the like) are commonly connected to vacuum drainage systems  10 . 
   The collection tank  20  provides a point where the waste can collect. The tank  20  includes a lower drain  40  that allows for the removal of the accumulated waste at periodic intervals or whenever the tank  20  is full. The waste enters the tank near the top where a low-pressure air space  45  is maintained. The vacuum pump  25  also connects to the tank  20  near the top so that operation of the vacuum pump  25  at least partially evacuates the air in the low-pressure air space  45  of the tank  20 . The evacuation of air in the low-pressure air space  45  acts to reduce the pressure within the tank  20  and draws air in from the piping  30  attached to the tank  20 . In this manner, the vacuum pump  25  is able to produce at least a partial vacuum within a portion of the piping  30  and  70  of the vacuum drainage system  10 . It should be noted that the terms “low-pressure” and “vacuum” are used interchangeably herein to describe a region having a pressure below the local atmospheric pressure. Thus, the term “low-pressure” should be understood to mean a region having a pressure below atmospheric pressure. In addition, the term “vacuum” should be understood to include partial vacuums (i.e., any pressure below atmospheric). 
   An accumulator  50  is in fluid communication with the sink  15  to receive a flow of waste. While a single accumulator  50  is illustrated as being associated with a single sink  15 , it should be understood that multiple accumulators could be associated with each source or multiple sources could feed a single accumulator. Waste from the sink  15  flows under the force of gravity to the accumulator  50  where it collects. The accumulator  50  provides a small storage area for waste, thereby allowing for the collection of a larger amount of waste and a longer duration between vacuum applications. 
   As shown in  FIGS. 2 and 3 , a riser  55  interconnects the accumulator  50  and the portion of the piping  30  (shown in  FIG. 1 ) in the system that is subjected to the partial vacuum. The riser  55  includes a first portion  60  that attaches to the accumulator  50  and a riser valve  65  connected to the first portion  60 . The riser valve  65  separates the first portion  60  from a second portion  70 . The second portion  70  is in fluid communication with the portion of the piping system subjected to a partial vacuum. Thus, the riser valve  65  separates a vacuum portion of the piping  75  from the accumulator  50 . 
   As illustrated in  FIGS. 1–3 , the riser  55  is a substantially vertical pipe arrangement. However, it should be understood that there is no requirement that the riser  55  be oriented vertically or that the riser  55  actually change in elevation. The riser length and orientation is largely a function of the location of the source relative to the collection tank  20 . 
   The position of the riser valve  65  relative to the accumulator  50  can effect system operation. Therefore, it is desirable to locate the riser valve no more than four feet above the elevation of the accumulator  50 , with lower locations being more preferred. However, it should be understood that many other factors (e.g., pipe diameter, piping arrangement, vacuum pressure, atmospheric pressure, etc.) can effect system performance and will allow systems to function with riser valves  65  located at elevations greater than four feet above the accumulator  50 . 
   As illustrated in  FIGS. 2 and 3 , a controller  80  operates the riser valve  65  to facilitate the removal of the waste collected within the accumulator  50 . One possible controller  80  is similar to the controller  80  described in U.S. Pat. No. 6,311,718 the entire contents of which are incorporated herein by reference. Other types of controllers, such as solenoid-operated actuators, will also function with the present invention. In fact, the actual arrangement of the controller is not critical to the function of the present invention. The controller  80  includes a first tube  85  that provides fluid communication between the accumulator  50  and the controller  80  and a second tube  90  that provides fluid communication between the controller  80  and the riser valve  65 . 
   The first tube  85  has an open end positioned within the accumulator  50  such that as the accumulator  50  fills, the end of the tube  85  becomes submerged. Once submerged, the end of the tube  85  is subjected to hydrostatic pressure that varies with the depth of the liquid within the accumulator  50 . Thus, the tube  85  is able to measure a pressure change within the accumulator  50  even though the accumulator  50  is exposed to atmospheric pressure. 
   With reference to  FIG. 2 , the vacuum drainage system  10  also includes an aeration system  95  connected in a manner that allows for the admission of air downstream (on the vacuum side) of the riser valve  65 . The aeration system  95  includes an air admittance valve  100  having a tube  105  connected to the second tube  90  and an air tube  110  connected to the second portion  70  of the riser  55 . The tube  105  can be formed from any suitable material so long as it can provide fluid communication between the second tube  90  and the air admittance valve  100 . The fluid communication allows the vacuum pressure within the second tube  90  to be used to actuate the air admittance valve  100 . Thus, when the pressure within the second tube  90  reaches a predetermined value (either rises above or falls below depending on the arrangement of the controller  80 ), the air admittance valve  100  opens. Many types of air admittance valves  100  will function with the present invention. Thus, while a vacuum pressure-actuated valve is described herein, the invention should not be limited to vacuum pressure-actuated valves alone. 
   When the air admittance valve  100  is open, air is drawn through an air inlet  115 , through the air tube  110 , and into the second portion  70  of the riser  55 , which is maintained under a partial vacuum by the vacuum pump  25 . Thus, the air tube  110  should be formed from a material that is suited to the purpose (e.g., metals, such as copper, steel, stainless steel, or plastics, rubber, composites, ceramics, and the like). 
   The location in the second portion  70  of the riser  55  at which the air tube  110  penetrates the riser  55  (i.e., the aeration point  120 ) is not critical. However, it is desirable to position the aeration point  120  as near to the riser valve  65  as possible without interfering with the function of the riser valve  65 . A position between 1 inch and 12 inches downstream of the riser valve  65  is preferred. 
   Turning to  FIG. 3 , another embodiment of an aeration system  95   a  is illustrated. The system of  FIG. 3  is similar to that of  FIG. 2  with the addition of a timer  130  and a check valve  135 . Any common timer  130  and check valve  135  can be used with the present system  10  to achieve the desired functionality. For example, a timer that begins a timing cycle when the air admittance valve  100  and riser valve  65  open and times out after a predetermined period of time passes following the closure of the riser valve  65  is well suited to the purpose. Until the timer  130  times out, the air admittance valve  100  remains in the open position. Once the timer  130  times out, the pressure within the second tube  90  reaches the air admittance valve  100  and causes it to close. Both the timer  130  and the check valve  135  are positioned in the pressure tube  105  and provide additional functionality that will be described in conjunction with the overall system function. 
     FIG. 5  illustrates another construction of a vacuum drainage system  10   a  that includes several aeration stages  140 . The system  10   a  includes the source such as one or more sinks  15  that feeds waste to one or more accumulators  50  as was described with regard to  FIG. 1 . In addition, the system  10   a  includes a controller  80  similar to the one described with regard to  FIGS. 1–3 . The controller  80  operates in much the same manner as was described above. However, in the construction of  FIG. 5 , the controller  80  operates to actuate three air admittance valves,  100   a ,  100   b , and  100   c  that admit air at three air admittance points  120   a ,  120   b , and  120   c.    
   The riser  55   a  includes a first portion  145 , a second portion  150 , a third portion  155 , and a fourth portion  160 . The first portion  145  is in fluid communication with the accumulator  50  and is separated from the second portion  150  by the riser valve  65 . The second portion  150  is separated from the third portion  155  by the second air admittance point  120   b . The third portion  160  is separated from the fourth portion  165  by the third air admittance point  120   c . The fourth portion  165  is in fluid communication with the vacuum portion of the piping  75 . It should be noted that in many constructions, the second portion  150 , the third portion  155 , and the fourth portion  160  are formed from a single pipe. The air admittance points  120  define the break between the portions  155 ,  160 ,  165 . However, the portions  155 ,  160 ,  165  are still formed from a single pipe and, in most constructions, cannot be “separated” from one another. 
   The aeration points  120   a ,  120   b ,  120   c  receive a flow of air from the independent air admittance valves  100   a ,  100   b ,  100   c . Each air admittance valve  100   a ,  100   b ,  100   c  is actuated in response to the pressure within the second tube  90  as described with regard to  FIGS. 1–3 . The use of multiple air admittance points  120   a ,  120   b , and  120   c  can improve the aeration of the waste as the waste travels to the tank  20 . 
   While the aeration stages  140  of  FIG. 5  are arranged as illustrated in  FIG. 3  to include a check valve  135  and a timer  130  in each stage, other constructions may employ the arrangement of  FIG. 2 . In addition, different combinations or arrangements may be used as required by the system design. Furthermore, multiple controllers  80  or multiple riser valves  65  could be used if desired. For example, one possible system includes a controller  80  for each aeration stage  140 . As one of ordinary skill will realize, many combinations of valves  80 ,  100  will function with the present system. 
   In another construction illustrated in  FIG. 4 , the system  10   b  includes a single air admittance valve  100  that feeds multiple air admittance points  120 . In this construction, the controller  80  actuates the air admittance valve  100  to admit air to three air admittance points  120   a ,  120   b , and  120   c . As with previous constructions, the aeration station  140  could include a check valve  135  and a timer  130  if desired. 
     FIGS. 4 and 5  illustrates systems  10   a ,  10   b  having three aeration stages  140 . It should be understood that fewer aeration stages  140  could be used or more aeration stages  140  could be used as desired. There is no limit to the quantity of aeration stages  140  used with the present invention. 
   With reference to  FIGS. 1 and 2 , the operation of the vacuum drainage system  10  will now be described. Following use of the sink  15 , waste drains into the accumulator  50  (with gravity as the motive force). With continued or numerous uses, the waste level within the accumulator  50  rises. Once the end of the tube  85  is submerged, the hydrostatic pressure the tube  85  is subjected to varies with the liquid level within the accumulator  50 . Thus, as the waste level rises, the pressure within the first tube  85  between the controller  80  and the accumulator  50  increases. At a predetermined pressure, corresponding to a particular waste level within the accumulator  50 , the pressure is sufficient to initiate the controller  80 , which in turn actuates and opens both the riser valve  65  and the air admittance valve  100 . 
   With the riser valve  65  now open, the first portion  60  of the riser  55  and the accumulator  50  are in fluid communication with the collection tank  20 . As such, the low pressure draws the waste out of the accumulator  50  and the first portion  60  of the riser  55  and moves the waste toward the collection tank  20 . At the same time, an amount of air is drawn into the second portion  70  of the riser  55  through the air admittance valve  100 . The air serves to break-up the waste into an emulsion (air-waste mix) that is more easily lifted by the vacuum. If the waste stalls with the air-admittance valve  100  open, the air entering the second portion  70  will act to push the waste from the aeration point  120  to the vacuum tank  20  while simultaneously breaking-up the waste. 
   As the waste is drawn out of the accumulator  50 , the waste level within the accumulator  50  drops, thereby causing the pressure within the first tube  85  to drop in a similar fashion. Once the pressure within the first tube  85  reaches a predetermined value, the controller  80  actuates and closes both the riser valve  65  and the air admittance valve  100 . 
   The operation of the construction of  FIG. 3  is similar to that of  FIG. 2  up to the point at which the valves  65 ,  100  close. The timer  130  allows the air admittance valve  100  to remain open after the riser valve  65  closes. With the air admittance valve  100  open, the vacuum continues to draw in air through the air admittance valve  100 . The timer  130  delays the closure of the air admittance valve  100  for a predetermined length of time. In many constructions, the timer  130  is adjustable to vary the length of time that the air admittance valve  100  remains open after closure of the riser valve  65 . The continued admittance of air after the closure of the riser valve  65  serves to reduce the quantity of waste that flows back or remains within the second portion  70  of the riser  55  after the valves  65 ,  100  close. 
   The construction of  FIG. 4  functions much like the construction of  FIG. 1 . The exception being that when the air admittance valve  100  opens, air is directed to three aeration points  120   a ,  120   b , and  120   c  rather than a single aeration point  120 . 
   The construction of  FIG. 5  functions in much the same manner as the system  10  of  FIG. 1 . In one arrangement, all of the air admittance valves  100   a ,  100   b ,  100   c  open and/or close at substantially the same time. This allows for the admittance of air at multiple elevations along the waste column. 
   In another system, the air admittance valves  100   a ,  100   b ,  100   c  open and/or close in sequence rather than simultaneously. Timers can be employed to achieve the desired time intervals between the opening and closing of the various valves  100   a ,  100   b ,  100   c . In addition, other control systems (e.g., microprocessor-based controls, PLCs, relay controls and the like) can be used to control the various valves in the system. 
   Although the invention has been described in detail with reference to certain preferred embodiments, variations and modifications exist within the scope and spirit of the invention as described and defined in the following claims.