Abstract:
A universal drum lid for vacuum systems comprises an inlet port configured to intercept downwardly flowing influent at a baffle and engage a direction plate which redirects the flow laterally against an adjacent side wall of the receptacle. An outlet port is shielded by the direction plate. Maximum liquid removal and minimal liquid carryover is achieved through the use of the drum lid. Preferably, a disengagement chamber precedes the baffle for disengaging suspended particles, including liquid, and permitting debris to pass the baffle without blockage. A single float ball-valve is sensitive to flow and will seal the outlet on high liquid entrainment and on high liquid levels.

Description:
FIELD OF THE INVENTION  
         [0001]    The present invention relates generally to a lid for open top containers in a vacuum system for facilitating the removal of solids and liquids from an air stream. More particularly, the invention relates to a lid which is adaptable to open-top containers, minimizes liquid carryover out of the container, and enables liquid level control.  
         BACKGROUND OF THE INVENTION  
         [0002]    In the area of environmental clean up, vacuum systems are frequently used to recover liquids, sludge and dry products. In such cases it is useful to remove these recovered particles or liquid from the stream of air prior to the stream entering the main vacuum system. Conventional systems comprise a vacuum generating device, a suction source line extending between the vacuum generating device and an outlet port on an intermediate collection receptacle, and suction wand connected to an inlet port to the receptacle.  
           [0003]    Intermediate collection receptacles are often utilized in situations where one does not want hazardous materials carried through to a main vacuum source. Receptacles such as drums and canisters are inexpensive, readily available and can hold a large amount of particulates and liquid. Furthermore, once a drum or canister is full it can be transported to a disposal or storage site, should this be required.  
           [0004]    As is typically the case with accidental spills, the liquid can be hazardous including having flammable characteristics. Vacuuming can volatilize or atomize the liquid which can accentuate the hazard if entrained in the discharged flow and carryover beyond the collection container.  
           [0005]    In U.S. Pat. No. 5,525,396 to Rudolph et al. a particle collector lid is described. This lid is adapted to close off the upper end of a container and provides inlet and outlet chambers shaped so as to direct air entering the container to flow in a curved and downwardly inclined direction. This directing of air establishes a cyclonic action in the container which results in separating out larger particles, such as wood chips, from the air stream. However, the device disclosed by Rudolph et al. does not work well when extracting liquids from a stream of air for a number of reasons. First, the cyclonic action does not encourage knock-out of liquid from the air stream and some entrained liquid will exit through the outlet chamber and into the main vacuum system. Second, once the container is full, any additional liquid overflows into the outlet chamber and is likewise sucked into the main vacuum system.  
           [0006]    A transparent lid, as taught by U.S. Pat. No. 6,210,457 to Siemers, allows an operator to visually inspect the amount of particles or liquid collected in a container. However, such a device still requires continuous observation of the growing amount of liquid inside and risks liquid overflowing into the main vacuum system if left unobserved. This device also does not address the liquid entrainment problem.  
           [0007]    One device that prevents an overflow of liquid into the main vacuum system is the Drumlt™ device manufactured by Elastec Inc. of Carmi, Ill. The Drumlt™ lid includes a two-ball valve at the container exit to shut off the air flow when the drum is full of liquid. However, from experience the applicant has found that interaction of the two balls can result in an improper seal. Furthermore, applicant has found this system to have a high entrained liquid carryover. Applicant hypothesizes that stream of air and liquid is directed against the bottom of the container (or top any collected liquid) which results in some of the liquid remaining entrained in the stream of air or being re-entrained. The two-ball valve is insensitive to increased liquid carryover, activates only upon high liquid contact and is slow to respond. These deficiencies limit the Drumlt™ device&#39;s ability to remove liquid from the stream of air resulting in passage of a higher than desirable amount of liquid to the vacuum generating device.  
           [0008]    In U.S. Pat. No. 5,970,573 to Lahaye, spray and incoming mist is discharged from a nozzle at an inlet port and is directed downwardly to the bottom of the container, deliberately away and separated from the outlet port and vacuum blower by a depending weir or direction plate. Lahaye has attempted to address the entrainment problem to some extent, however, like the Drumlt™ device, liquid entrainment can still result and the direction plate extends deeply into the container affecting its fill capacity.  
           [0009]    Accordingly, there is still a need for an apparatus and method for adapting to easily procured receptacles such as drums, that limit liquid entrainment in a stream of air, and that provide reliable shut off in high liquid situations. Additionally a need exists, beyond the prior art, for a device or method to control accumulations of liquid so as to maximize vacuuming operation.  
         SUMMARY OF THE INVENTION  
         [0010]    In one aspect of the present invention, a universal drum lid for vacuum systems is provided for fitting to open top receptacles and maximizing liquid knockout, minimizing liquid entrainment resulting in liquid carryover from the receptacle.  
           [0011]    In another aspect of the invention, a lid is provided for superior liquid collection management while retaining the ability to maximize liquid knockout and minimize liquid carryover from the receptacle.  
           [0012]    In one embodiment of the invention, an inlet port is configured to intercept downwardly flowing influent with a baffle and redirect the flow perpendicularly or laterally against an adjacent side wall of the receptacle which is opposing or away from the ultimate exit. Through the addition of a preferred disengagement chamber above the baffle, influent velocity is reduced for disengaging suspended particles, including liquid, and permitting debris to pass the baffle without blockage. Preferably the baffle is suspended below the lid and in the path of the influent by a blocking plate which isolates the inlet port from the outlet port. For minimizing liquid carryover out of the outlet port, preferably the outlet port comprises a single float ball-valve which is configured to close the outlet port even prior to the float ball contacting a collected high liquid level surface.  
           [0013]    In another aspect of the invention, a drum lid is provided which includes a combination of elements which enable substantially continuous management of liquid collection and removal. The preferred lid includes a downcomer conduit which is adapted for connection to a liquid removal device such as a suction pump. Such a system draws any collected liquid from a location sufficiently below the outlet port so that the float ball is not actuated and the characteristics of the flow steam approaching the outlet port do not actuate the ball valve. In the case of a conventional drum, it is advantageous to extend the conduit to the bottom of the drum.  
           [0014]    Accordingly, in a broad aspect of the invention, a planer lid is provided comprising an inlet port fit into and located adjacent a periphery of the lid and oriented for receiving the mixed stream and redirecting it downwardly into the container adjacent a vertical side wall; a baffle spaced from and positioned below the inlet port so as to intercept the mixed stream and redirect the stream laterally; a plate depending from the lid adjacent the inlet port and extending downwardly to the baffle for blocking at least a portion of the laterally redirected stream so that substantially all of the laterally redirected stream is towards the side wall for removing a substantive amount of liquid from the mixed stream; and an outlet port fit into the lid and adapted for connection to a vacuum source, the outlet port spaced from the inlet port and plate for discharge of the gas stream.  
           [0015]    Preferably, the lid comprises a chamber to which the inlet port is connected, the chamber having greater lateral dimensions than the inlet port and the baffle. More preferably, the chamber is raised above the planer lid so as to enable closer spacing of the baffle to the lid.  
           [0016]    In another aspect, a conduit is also depending from the lid to a suction end for engaging collected liquid and when adapted to a pump, liquid can be withdrawn on a substantially continuous basis. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0017]    [0017]FIG. 1 is an overall view of the one embodiment of the invention including the vacuum source, drum and wand;  
         [0018]    [0018]FIG. 2 is a partial side view of an embodiment of the drum lid affixed to a drum (shutoff valve omitted for clarity);  
         [0019]    [0019]FIG. 3 is an underside plan view of the drum lid according to FIG. 2;  
         [0020]    [0020]FIG. 4 is a top plan view of the drum lid according to FIG. 2;  
         [0021]    [0021]FIG. 5 is a perspective view of the lid of FIG. 2 illustrating the inlet port, and baffle;  
         [0022]    [0022]FIG. 6 is an underside plan view of an embodiment of the drum lid of FIG. 2 with a shutoff valve attached;  
         [0023]    [0023]FIG. 7 is a side perspective view of another embodiment of the drum lid having a conduit for liquid removal fit thereto;  
         [0024]    [0024]FIG. 8 is a top perspective view of the lid of FIG. 7, fit to a drum and having a schematic representation of a suction pump connected to the suction conduit;  
         [0025]    [0025]FIG. 9 is a side perspective view of another embodiment of the drum lid having a conduit for liquid removal fit thereto; and  
         [0026]    [0026]FIG. 10 is a top perspective view of the lid of FIG. 9, fit to a drum and having a schematic representation of a suction pump connected to the suction conduit. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0027]    [0027]FIG. 1 illustrates a vacuum system  1  comprising a vacuum source  15 , a suction source line  13  extending between the vacuum source  15  and an outlet port  14  on an intermediate collection receptacle  18 , a suction wand  3 , and a debris hose  11  connected to an inlet port  12  at the receptacle  18 . The source line  15  and debris hose  11  are conduits capable of accepting working vacuum without collapse. The receptacle  18  is a container or drum having a closed bottom, vertical side walls  9 , an open top  19  and has a detachable or removable lid  10 . Typical vacuum at the drum  18  is about 7 inches wc. Suitable controls known to those of skill in that art are applied to the system to ensure safe operation including shutoff controls to avoid over-vacuum collapse of the hose or container. With pressure controls set at 9-10 inches wc, conventional drums with 18 gauge wall thickness can be used.  
         [0028]    With reference to FIGS.  1 - 5 , one embodiment of the lid  10  is a flat plate or planer structure which is sized for the drum  18  and which has a periphery  17  which is adapted to seal to the drum&#39;s open top  19 .  
         [0029]    The debris hose is  11  is connected to the inlet port  12  which is located near the periphery  17  of the lid  10 . The suction line  13  is connected to the outlet port  14  which is generally located at the center of the lid  10 . The suction source line  13  connects to the vacuum source  15 . Preferably, the vacuum source  15  is a regenerative blower such as model 2BH1600 available from Siemens of Germany. A blower  15  provides a low temperature driver for moving the air flow. It is particularly advantageous to use a non-roots type blower as some waste liquid may be flammable and positive displacement blowers create a high temperature ignition source. More preferably, the blower  15  is driven by a diesel engine thereby further avoiding electrical ignition sources.  
         [0030]    The planer structure of the lid  10  has upper and lower surfaces  10   a ,  10   b  and an edge  16  at the periphery  17  that is suitable for engaging the top opening  19  of the drum  18 . A suitable drum  18  is a 45 US Gal. or 200 liter barrel or drum. Drums for receiving hazardous influent include those approved pursuant to Canadian legislation, specifically the Transportation of Dangerous Goods Act. The lid  10  is generally circular and generally closes off the top opening  19  of the drum  18 . In this embodiment the diameter of the lid  10  is approximately  22 ″ so as to fit over, and seal the open top  19  of the approved 200 liter drum  18 .  
         [0031]    The lid&#39;s inlet port  12  and an outlet port  14  enable the flow of air into, and out of, the drum  18  as is shown by arrows  30 ,  32  (FIG. 1).  
         [0032]    The inlet port  12  is formed by a linear section of conduit  12   c  preferably connected near the periphery  17  of the lid  10 . The debris hose  11  connects inline with the conduit  12   c  so as to direct influent substantially downwardly  29  through the lid  10  and into the drum  18 . The influent is an air stream typically comprising air and possibly further comprising a mixed stream of air, liquid, particulates and any other debris.  
         [0033]    The inlet port  12  has a flow modifying structure  20  which acts to re-direct the incoming influent and thereby minimize carryover of liquid to the outlet port  14 . This flow modifying structure  20  has an “L”-shaped profile in section and comprises a horizontal baffle  24  and a vertical plate  22  depending from the lid  10 . The plate  22  is located intermediate the inlet port  12  and the outlet port  14 . The baffle  24  interrupts and re-directs the air stream  30  substantially laterally within the drum  18  and the plate  22  blocks a portion of the lateral flow and thereby limits the air stream to a 180 sweep directed laterally at the wall of the drum  18 . Conveniently, the plate  22  also serves to support the baffle  24  from the lid  12 .  
         [0034]    Preferably, the flow modifying structure  20  further comprises an abrupt widening of the inlet port  12  which is achieved by provision of a chamber  12   b  formed in the lid  10  and located prior to the baffle  24 . The air stream is affected in at least several ways, all of which aid in minimizing liquid entrainment and reliability of operation. First, the abrupt increase in cross-sectional flow area, before reaching the drum  18  causes a relatively rapid reduction in velocity of the air stream. Secondly, the chamber  12   b  provides a much wider inlet port  12  prior to the baffle  24  thereby being less likely to be blocked by bulky debris.  
         [0035]    The increase in cross-sectional area first at the chamber  12   b  and then into the drum  18 , and further through the abrupt change in air stream flow at the baffle  24  appear to causes a large portion of the entrained liquid to precipitate out into the drum  18  and avoid re-entrainment. The baffle  24  is positioned directly below the inlet port  12  and intercepts the fastest flowing of the air stream and directs the air stream substantially towards the side of the drum  18  at an angle substantially more towards the perpendicular than in a typical cyclonic vacuum system. The baffle  24  has a surface area comparable to the cross sectional area of the inlet port  12  just prior to the chamber  12   b  and is positioned substantially vertically below the inlet port  12 . The baffle  24  is smaller than the cross-sectional area of the chamber  12   b  thereby providing greater free space for the passage and release of debris into the drum  18 . In the preferred embodiment, the baffle  24  is attached to the distal end of the plate  22 , being spaced slightly below the lower surface  10   b . Such a baffle  24  is optimally arranged for intercepting the influent entering through the inlet port  12  while at the same time not acting as a collecting platform for debris that may happen to be mixed in the stream of air and liquid (as is common in environmental clean ups in areas of muskeg). However, larger baffles having differing relative dimensions could be utilized, especially in cases where entrained debris is not a problem.  
         [0036]    For maximum utility, when vacuuming liquid materials into the drum  18 , it is often desirable to allow the container  18  to be filled with as much liquid as possible before the lid  10  ceases to function properly. One approach is to position the baffle  24  as close to the lid&#39;s lower surface  10   b  as possible but far enough to allow for debris to flow past the baffle  24 . Advantageously, the chamber  12   b  is connected to the lid&#39;s upper surface  10   a , and extends thereabove so as to minimize the projection of the baffle  24  into the drum  18 . A curved conduit  12   a  is connected between the inlet port  12  and the suction source line  13 .  
         [0037]    Now referring to FIGS.  6 - 7  in an additional embodiment, a novel ball valve arrangement  40  is fit to the outlet port of the lid  10  for maximizing air stream therethrough while reducing the risk of liquid carryover. The valve  40  projects minimally into the drum  18  for maximum drum storage capacity. The valve  40  utilizes a single ball  42  constrained inside a frame or cage  46 . Unlike conventional double ball-type liquid level arrangements, a ring seal  44  is located at the lid interface  10   b  which ensures effective sealing when the flow dynamics around the ball  44  sense the passage of dense, liquid entrained flow such as that which can occur just prior to liquid level shutoff.  
         [0038]    More specifically, a collar  45  is fit to the outlet port  14  of the lid  10 . The collar  45  has a bore which is threaded for coupling with the valve  40  below the lid  10  and with the vacuum source line  13  above the lid  10 . The collar  45  is fit with an elastomeric ring seal  44  at the interface of the cage  46  and collar  45  for cooperating with the ball  42  in sealing the outlet port  14 . Preferably, the collar  45  is fit with a sight glass  47  and tee  49  before connecting to the vacuum source line  13 .  
         [0039]    The cage  46  projects downwardly, into the drum  18 , for supporting the ball  42  underneath the lid  10 . The ball  42  is able to travel vertically inside the cage  46  in response to the passage of dense, liquid entrained air flow. This valve arrangement  40  of a single responsive ball  42 , a positive seal  44  at the lid interface  10   b  and a minimum travel cage  46  results in a maximum sensitivity and effective shut-off upon the presence of dense, liquid entrained flow.  
         [0040]    As stated earlier, there is an ongoing concern regarding liquid storage capacity a drum  18  and the risk of higher liquid entrainment and resultant carryover as liquid levels approach the lid. Accordingly in two other embodiments, and referring to FIGS.  7 - 8  and  9 - 10 , the lid  10  is further enhanced through the additional of a liquid withdrawal system  50  for substantially continuous and ongoing removal of liquids from the drum  18  while operating under vacuum. To accommodate the system  50 , the lid  10  is fit with a coupling or liquid withdrawal port  52  and conduit or stinger  51  depending therefrom. The stinger  51  extends downwardly for engaging any collected liquids. The stinger  51  comprises a pump end  51   a  at the liquid withdrawal port  52  and a suction end  51   b  extending downwardly. Specifically, the stinger  51  extends from the liquid withdrawal port  52  at the lid  10  and with the suction end  51   b  extending downwardly to towards the bottom of the drum  18 .  
         [0041]    The liquid withdrawal port  52  is adapted for connection to a suction line  55  for connecting the stinger  51  to a pump  56  for withdrawal of accumulated liquids from the container or drum  18 . Preferably, and so as to maintain the integrity of the vacuum system  1  while operating, the pump  56  is a positive displacement pump. Alternatively, a different type of pump  56  could be used if a check valve (not shown) were to be placed between the pump  56  and the stinger  51 .  
       EXAMPLE  
       [0042]    As shown in the FIGS.  1 - 8 , in one application of the invention, a 250 scfm blower constituting the vacuum source  15  was fit to a 200 liter open top drum  18 . A lid clamp secured the lid  10  to the drum  18 . The lid  10  was approximately 22″ in diameter. A 3″ pipe inlet port  12  is coupled to a disengagement chamber  12   b  which measures about 3½″ by 8″ wide by about 2″ high above the lid  10 . The direction plate  22  extends downwardly from the lid  10  about 2″ with a 8″ width to redirect influent away from the outlet port  14 . A baffle  24  is positioned substantially centered below the inlet port  12 . The baffle plate  24  is supported by the direction plate  22  and extends laterally towards the periphery of the lid  10  and thus towards the drum wall. The baffle  24  is smaller than the chamber opening and measures approximately 3½″ laterally or radially and about 4″ in width or 4″ shorter than the chamber width and providing about 2″ free either side of the baffle plate  24  for shedding debris. Direction plates  22  of other dimensions could be utilized as long as the plate  22  is of a sufficient size to direct the air stream away from the outlet port  14  and to support the baffle  24 . Baffles  24  of other dimensions could be utilized, especially in cases where entrained debris is not a problem. This chamber  12   b  enables the baffle  24  to be close to the lid&#39;s lower surface  10   b  while preventing debris from being caught in the inlet  12  by the baffle  24 . A 6″ diameter outlet port  14  is fit with a ring seal  44  which seals against a conventional 6″ ball  42 . The lid collar  45  is fit with a sight glass  47  and tee  49  before connecting to the vacuum source line  13 . Quick connect couplings are provided at both the inlet port  12  and for the vacuum source line  13 .  
         [0043]    The advantages of the system include:  
         [0044]    decreased liquid entrainment and carryover in a stream of air;  
         [0045]    maximum sensitivity and effective shut off upon the presence of dense, liquid entrained flow;  
         [0046]    decreased debris collection and blockage in the inlet port; and  
         [0047]    the capability of ongoing removal of liquids from the drum while operating under vacuum.