Abstract:
A pressure vessel includes a lid being rotatable into an unlocked position by a first actuator and then raised vertically above its housing by a second actuator secured along the housing. A pressure safety latch is provided to both vent the vessel before the Hd is moved into its unlocked position and release the lid for unlocking rotatable movement.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to a liquid filter and will have particular application to pressurized filtration vessels. 
     2. Description of the Background of the Invention 
     The following description describes a pressure vessel which is an improvement upon the vessel and vessel lock-down system disclosed in U.S. Pat. No. 5,918,756. The content and disclosure of the aforementioned patent is incorporated herein by reference. 
     SUMMARY OF THE INVENTION 
     The present invention is a lock-down system for a pressurized filtration vessel in which the vessel lid may be locked and unlocked from the vessel housing. The vessel housing carries a davit arm which extends over the vessel and supports the lid. The housing includes an upper cylindrical portion which engages the lower cylindrical side edge of the lid. The plurality of radially extending catch members are disposed at intervals above the housing cylindrical portion. A corresponding plurality of hook-shaped retaining members extends downwardly from the lid side edge to overly the cylindrical portion of the housing when the lid is lowered onto the housing. With the lid situated on the housing, a drive is provided between the housing and the lid and when activated causes the lid to rotate with the retaining members engaging the catch members to draw the lid downwardly into sealing engagement with the housing. The lid is removed by reversing the direction of this drive and operating a lift piston which is located along the side of the housing and which raises the lid after its opening rotating movement upwardly so as to provide clearance for exchanging the filtration elements within the vessel housing. 
     Accordingly, it is an object of this invention to provide a vessel lock-down system for a pressurized filtering vessel in which the lid can be quickly attached and detached from the vessel housing. 
     Another object of this invention is to provide a vessel lock-down system for a liquid filtration vessel in which the lid when unlocked from the housing may be extended directly upwardly to expose the interior of the vessel housing. 
     Still another object of this invention is to provide a pressurized filtration vessel having a pressure release safety latch assembly for the purpose of depressurizing the vessel before the lid is unlocked. 
     And still another object of this invention is to provide a pressurized filtration vessel that is safe to use. 
     And still another object of this invention is to provide a pressurized filtration vessel that includes shielding to reduce outer spray from the interior of the vessel upon opening of the vessel lid. 
     Other objects of this invention will become apparent upon a reading of the following description. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A preferred embodiment of this invention has been chosen for purposes of illustration and description wherein: 
         FIG. 1  is a perspective view of a pressure vessel incorporating the lock down system of this invention; 
         FIG. 2  is a side view of the pressure vessel; 
         FIG. 3  is a side view of the pressure vessel showing the lid unlocked and raised and a filtration element being removed for illustrative purposes; 
         FIG. 4  is a top plan view of the pressure vessel with a portion of the vessel lid fragmented for illustrative purposes, showing the filtration elements within the vessel housing; 
         FIG. 5  is an elevational view of the pressure vessel with a portion of the vessel lid and housing removed for illustrative purposes to show fluid flow through the vessel; 
         FIG. 6  is a fragmentary view of the hydraulic controls for the pressure vessel as seen from above; 
         FIG. 7  is a detailed view showing a lid-retaining member lockingly engaged with a catch member of the vessel housing, securing the lid to the housing; 
         FIG. 8  is a top view of the hydraulic controls showing the actuating lever moved into its open position; 
         FIG. 9  is a detailed view similar to  FIG. 7  but showing the retaining member released from the vessel housing catch member and the lid loosened for lifting; and 
         FIG. 10  is a hydraulic fluid flow diagram showing the actuating and flow control elements of the invention. 
     
    
    
     DETAILED DESCRIPTION OF INVENTION 
     The preferred embodiment illustrated is not intended to be exhaustive or to limit the invention to the precise form disclosed. It is chosen to describe and best illustrate the invention and to enable one having ordinary skill in the art to utilize the invention. 
     Pressure vessel  10  of the subject invention includes a body or housing  12 , a lid  14  and a hydraulic actuation or control system  16 , best shown in detail in  FIG. 10 . Housing  12  is supported by legs  18  and includes a cylindrical side wall  20  and upper cylindrical portion  24 . Cylindrical portion  24  carries an o-ring  30  which provides a seal between lid  14  and housing  12  when the lid is in its closed and locked position. A plurality of filter bags  32  or similar filtration elements are supported within housing  12 . Liquid flow represented by arrows  33  in  FIG. 5  enters the vessel by way of inlet pipe  36 , flowing upwardly above and then downwardly into and through the filter bags  32  and thereafter out of the vessel by way of outlet pipe  38 . 
     A davit arm  40  is supported for extended and retracted vertical movement at the side wall  20  of vessel housing  12  by an upper sleeve bracket  42  and a lower sleeve bracket  44 . Davit arm  40  at its upper free end is connected to and supports lid  14 . In  FIGS. 1 and 2 , the davit arm is in its retracted position with the lid  14  seated upon housing  12 . In  FIG. 3 , the davit arm is in its extended position, lifting the lid  14  from the vessel housing  12  so as to expose the interior of the housing, thereby allowing filter bags  32  to be removed and replaced. 
     A plurality of lugs or catch members  58  are attached to the outer surface of cylindrical portion  24  of the vessel housing  12 . Each of the catch members  58  includes an inclined cam surface  68 . Catch members  58  are spaced at substantially equal angular intervals about cylindrical portion  24  with all cam surfaces  68  in the same plane which is substantially parallel to the top wall  26  of the vessel housing  12 . 
     A plurality of hook-shaped retaining members  80 , each having or including a finger  84 , are attached to the lid side edge  70  at spaced angular intervals corresponding to the spacing of catch members  58  attached to vessel housing  12 . Each retaining member finger  84  has an inclined cam surface  92 . The relationship and manner of operation of catch members  58  and retaining members  80  are more fully described in U.S. Pat. No. 5,918,756 which has been incorporated by reference. 
     Mounted to the top of lid  14  is a venting device  76  in association with a pressure gauge  77 . The pressure gauge  77  reads the internal pressure within the vessel when the lid  14  is secured and locked to the vessel housing  12  and the vessel is in filtering operation. Venting device  76  is used to vent the interior of the vessel prior to the unlocking and lifting of the lid. 
     Mounted to one side of vessel housing  12  is a pressure relief safety latch  100 . An upper latch part  110  is connected to side edge  70  of the lid and a lower latch part  112  is connected to cylindrical portion  24  of housing  12  with, preferably, an o-ring that is carried by the lower latch part so as to provide a seal between the upper and lower latch parts when the parts are in vertical overlying alignment as illustrated in  FIG. 1 . A vented opening  114  into the interior of lid  14  extends through upper latch part  110 . Vented opening  114  terminates in a nozzle end within the interior of upper latch part  110 . A plunger  116  fits slideably within lower latch part  112  and is shiftable upwardly into sealing engagement with a nozzle end of opening  114  in the upper latch part when the latch parts are in vertical alignment. Plunger  116  is secured by a toggle clamp  118  to the side wall  20  of vessel housing  12 . During normal operative operation, plunger  116  extends into upper latch part  110 , sealing opening  114  and preventing lateral movement, and thus opening movement of lid  14 , between the upper and lower latch parts. Upon the actuation of toggle  118 , plunger  116  is withdrawn from the interior of upper latch part  110 , permitting venting of the interior of the vessel through opening  114  and along a keyslot along the plunger to the atmosphere, allowing lateral movement of the upper and lower latch parts relative to each other as lid  14  is rotated into its open position. In this manner, pressure relief safety latch  100  prevents premature opening of lid  14  until the interior of the housing vessel has been appropriately vented. 
     The hydraulic control  16  is shown schematic form in  FIG. 10  and includes a pump  96  which is carried upon a table  98  connected to housing  12 . Appropriate tubing for the hydraulic fluid pumped by pump  96  connects various operative components, namely, a drive assembly  102  for rotating lid  14  relative to housing  12 ; and a lift or cylinder  104  for raising lid  14  relative to housing  12 . Pump  96  is manually operated through a handle  106 . The hydraulic fluid that flows through tubing  124  is controlled by control valve  111 . Cylinder  104  is connected between housing  12  and the lower end of davit arm  40  which is guided in vertical orientation for sliding movement by upper sleeve bracket  42  and lower sleeve bracket  44 . The piston rod  105  of cylinder  104  when extended and retracted causes the raising and lowering respectively of the davit arm  40  relative to housing  12 . Drive assembly  102  which rotates lid  14  includes a cylinder  103  which is connected or secured to side edge  70  of lid  14  and whose piston rod  107  is secured to davit arm  40 . A pivot connection  45  connects the davit arm to the top of lid  14  so that the lid is rotatable about a vertical axis relative to the davit arm. Therefore, upon actuation of cylinder  103  and the extension and retraction of its piston rod  105 , lid  14  rotates relative to the davit arm about a vertical axis. Adjustment plates  47  are connected each of the lid and davit arm and are interconnected by adjustment bolts  49 . By turning bolts  49 , the spacing between the plates can be varied and the lid leveled with the upper edge of the housing. 
     To operate the vessel lock down system of this invention, control valve  111  is biased from its closed position shown in  FIG. 6  in which enable valve  122  is depressed by the camming action of the directly overlying retaining member  80  (see  FIG. 7 ) into its open position shown in  FIG. 8 . At this time the venting device  76  is opened and the pressure relief safety latch  100  is released by the opening of toggle clamp  118  which withdraws plunger  116  from the upper latch part  110 , releasing the lid for rotation and venting the interior of the housing. Pump  96  is then actuated by the cranking of handle  106  to cause hydraulic fluid to pass through line  124  and control valve  111  into cylinder  103  which causes the retraction of its piston rod  105  and the resulting clockwise rotation of lid  14  relative to the vessel housing  12 . This causes each of the retaining members  80  to slide out from under engagement with overlying catch members  58  so as to free the lid for upward movement relative to the housing. A shield  113  is carried by upper latch part  10  and another shield  115  is flexed about and covers the joint between the lid  14  and housing  12 , being retained in clips  117  attached to retaining members  80 . Shields  113 ,  117  serve to deflect any spray coming from within the vessel. As retaining members  80  shift laterally relative to the housing, enable valve  122  passes over the outer surface of the overlying retaining member  80  so that when all engagement members  80  are free from the overlying catch members  58 , valve  122  has its probe  123  biased into on extended position to open the valve. With valve  122  now open, the hydraulic fluid provided by pump  96  is diverted into tubing  125  so as to enter cylinder  104 . Continued actuation on pump  96  by handle  106  now causes the piston rod  105  of cylinder  104  to extend causing the lifting of davit arm  40  within sleeve brackets  42  and  44  and the raising of lid  14  from housing  12 . Continued pumping on pump  96  causes the continued raising of lid  14  until the spring biased catch pin  182  which is carried by housing  20  at the davit arm is spring urged into an opening in the davit arm so as to secure movement of the davit arm relative to the sleeve bracket  44  and thus relative to housing  20 . At this time the actuation of pump  96  is ceased. 
     Once access to the interior of the filter vessel  10  is no longer needed, lid  14  may be lowered. With control valve  111  still in its open position, pump  96  is preferably actuated a few times to slightly further raise the lid and thus relieve the pressure upon catch pin  182 . At this time, catch pin  182  is withdrawn from the davit arm  40  and control valve placed in its closed position. This allows for reverse flow of the hydraulic fluid through the control valve  111  and lowering of lid  14  relative to housing  12  by gravity. A flow control valve  113  controls the rate of decent of the lid. Once the lid has been lowered onto housing  12 , pump  96  is actuated which causes the reverse flow of hydraulic fluid into cylinder  103  at lid  14  so as to cause the extension of rod  107  and the lid to rotate clockwise relative to housing  12 . The retaining members  80  each slide and are cammed under an overlying catch member  58  which draws the lid into sealing engagement with housing  18 . At the same time the retaining member  80  adjacent enabled valve  122  contacts and engages its probe  123  causing flow to cylinder  104  to be isolated in preparation for the next raising of the lid. Toggle clamp  118  of pressure relief safety latch  100  is now released to allow its plunger  116  to reenter upper latch part  110  so as to secure the lid against rotating movement relative to housing  12  and to seal vent  114  into the interior of the vessel. 
     The invention is not to be limited to the detail above given but may be modified in the scope of the amended claims.