Patent Publication Number: US-7216610-B2

Title: Pressure regulator for engine cooling system

Description:
This application claims priority under 35 U.S.C. § 119(e) to U.S. Provisional Application Ser. No. 60/491,704, filed Aug. 1, 2003, which is expressly incorporated by reference herein. 
    
    
     BACKGROUND 
     The present disclosure relates to cooling systems for engines, and particularly to cooling systems with coolant overflow tanks. More particularly, the present disclosure relates to pressure-relief valves in cooling system closures. 
     SUMMARY 
     In accordance with the present disclosure, a cooling system apparatus includes a coolant tank, an overflow tank arranged to receive fluid discharged from the coolant tank, and a pressure regulator. The pressure regulator is arranged to extend into the overflow tank normally to block flow of fluid between the coolant and the overflow tanks. 
     In illustrative embodiments, the pressure regulator includes a pressure-relief valve member and a biasing spring arranged normally to apply a biasing force to urge the pressure-relief valve member to assume a closed position. The pressure-relief valve and the biasing spring are located in the overflow tank. In certain embodiments, the biasing spring can be compressed to assume a predetermined state. 
     Also in illustrative embodiments, a compression controller is associated with the biasing spring. The compression controller is coupled to the overflow tank and configured to vary the biasing force applied by the biasing spring to the pressure-relief valve member. 
     An operator can use the compression controller to vary a “closure” force (e.g., the biasing force of the biasing spring) applied to maintain the pressure-relief valve member in a normally closed position. The compression controller can be mounted for rotary, linear, and/or other suitable movement relative to the overflow tank to change the biasing force of the biasing spring. 
     An operator can select a “lower” closure force by moving the compression controller relative to the overflow tank to “decompress” (i.e., relax) the biasing spring. In the case of a lower closure force, fluid extant in the extant tank can have a relatively low-pressure level and still “move” the pressure-relief valve member against the biasing spring to assume an opened position. 
     An operator can select a “higher” closure force by moving the compression controller relative to the overflow tank to “compress” (i.e., squeeze) the biasing spring. In the case of a higher closure force, fluid extant in the coolant tank must have a relatively higher pressure level to move the pressure-relief valve member against the biasing spring to assume an opened position. 
     Additional features of the disclosure will become apparent to those skilled in the art upon consideration of the following detailed description of illustrative embodiments exemplifying the best mode of carrying out the disclosure as presently perceived. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The detailed description particularly refers to the accompanying figures in which: 
         FIG. 1  is a diagrammatic view of a degas bottle for an engine cooling system in accordance with the present disclosure; 
         FIG. 2  is a sectional view of an illustrative embodiment of the bottle of  FIG. 1  showing compression of a coiled spring to exert a downward first biasing (closure) force on a pressure-relief valve member normally closing an opening in a coolant tank; 
         FIG. 3  is a view similar to  FIG. 2  showing further compression of the coiled spring to exert a larger downward biasing (closure) force on the pressure-relief valve member; 
         FIG. 4  is a view similar to  FIGS. 2 and 3  showing movement of the pressure-relief valve member upwardly against the coiled spring to allow pressurized fluid (e.g., liquid and/or vapor) to flow from the coolant tank into the overflow tank; 
         FIG. 5  is a view similar to  FIGS. 2–4  showing the pressure-relief valve member in a normally closed position and movement of a vacuum-relief valve member downwardly against a biasing force provided by another coiled spring to open a central aperture formed in the pressure-relief valve member to allow fluid (e.g., liquid and/or vapor and/or air) in the overflow tank to flow through the central aperture into the coolant tank; and 
         FIG. 6  is a sectional view of another illustrative embodiment of a degas bottle for an engine cooling system in accordance with the present disclosure showing a pressure-relief valve and a companion biasing spring located in an overflow tank. 
     
    
    
     DETAILED DESCRIPTION 
     A degas bottle or cooling system apparatus  10  is adapted to be coupled to an engine cooling system  12  as suggested diagrammatically in  FIG. 1 . One typical function of a degas bottle is to remove air from a coolant system. 
     A pressure regulator  14  in accordance with the present disclosure is included in degas bottle  10  as suggested diagrammatically in  FIG. 1  and illustratively in  FIGS. 2–5 . Pressure regulator  14  includes a pressure-relief valve  16 , a vacuum-relief valve  18 , a compression controller  20 , and an adjustor  22 . It is also within the scope of this disclosure to couple pressure regulator  14  to a radiator cap (not shown). In another embodiment illustrated in  FIG. 6 , compression controller  20  and adjustor  22  are omitted to provide a non-adjustable pressure regulator  14 ′ in degas bottle  10 ′. 
     Degas bottle  10  also includes a coolant tank  24  coupled to cooling system and an overflow tank  26  coupled to coolant tank  24  through a passageway  28 . Coolant tank  24  is formed to include an interior region  30  containing a pressurized liquid coolant  32 . Pressure regulator  14  is configured normally to close passageway  28  to block flow of a fluid such as liquid, vapor, and/or air between coolant tank  24  and overflow tank  26  via passageway  28 . 
     In the illustrative embodiment, a fill cap  34  is provided normally to close an inlet  36  that is configured to open into an interior region  38  of overflow tank  26  to allow users to admit liquid coolant  32  into interior region  38  of overflow tank  26 . A vent passage  40  is provided to conduct vapor and/or air to the atmosphere from overflow tank  26 . Although overflow tank  26  normally is mounted on and coupled to coolant tank  24  to form two liquid reservoirs in degas bottle  10  as suggested in  FIG. 1 , it is within the scope of this disclosure to position overflow tank  26  in spaced-apart relation to coolant tank  24  and use a hose (not shown) to define passageway  28 . 
     As suggested in  FIG. 1 , compression controller  20  is used to vary a biasing or “closure” force applied to maintain pressure-relief valve  16  in a normally closed position. Adjustor  22  is coupled to compression controller  20  and used by a technician to operate compression controller  20  to vary the closure force applied to pressure-relief valve  16 . By selecting a “lower” biasing or closure force, pressurized liquid coolant  32  and/or vapor  33  will vent from interior region  30  of coolant tank  24  into interior region  38  of overflow tank  26  through passageway  28  at a first tank pressure level. By selecting a relatively “higher” biasing or closure force, as suggested, for example, in  FIG. 3 , pressurized liquid coolant  32  and/or vapor  33  will vent from interior region  30  into interior region  38  through passageway  28  at a greater second tank pressure level. 
     Using adjustor  22  it is possible for a technician to vary the maximum pressure level that will normally exist in interior region  30  of coolant tank  24  (and in cooling system  12 ) quickly and easily. It is within the scope of this disclosure to provide a “pressure-level” scale  23  associated with adjustor  22  (as suggested in  FIG. 1 ) to provide a visual signal to the technician of the tank pressure level established by compression controller  20  using adjustor  22 . 
     Vacuum-relief valve  18  is configured to move to an opened position allowing liquid and vapor and air to flow from interior region  38  of overflow tank  26  into interior region  30  of coolant tank  24  whenever the tank pressure level in interior region  30  falls below a predetermined level. Vacuum-relief valve  18  normally is moved to assume a closed position, yet is configured to move to an opened position (in the manner described herein) regardless of the pressure-relief valve biasing or closure force established by compression controller  20 . 
     One illustrative embodiment of degas bottle  10  and pressure regulator  14  included in degas bottle  10  is shown in  FIGS. 2–5  in various modes of operation. Pressure-relief valve  16  comprises a pressure-relief valve member  50  and a biasing spring  52 . Vacuum-relief valve  18  comprises a vacuum-relief valve member  54  and a biasing spring  56 . 
     Compression controller  20  includes a spring mount  58  coupled to an outer end  60  of biasing spring  52  and a drive shaft  62  extending in an outward direction from spring mount  58  to mate with adjustor  22 . An inner end  61  of biasing spring  52  is coupled to pressure-relief valve member  50  as shown, for example, in  FIG. 2 . 
     Drive shaft  62  is received for rotation (or other movement) in a bore  64  formed, for example, in a ring  66  mounted in an aperture  68  formed in a top wall  70  of overflow container  26 . An O-ring seal (not shown) or other suitable seal is provided to establish a liquid and/or vapor seal between each of (1) ring  66  and top wall  70  and (2) ring  66  and drive shaft  62 . 
     External threads  63  on drive shaft  62  mate with internal threads  65  in bore  64  of ring  66  to cause drive shaft  62  to move inwardly in direction  71  in response to clockwise rotation of adjustor  22  (and drive shaft  62 ) about axis  72  and to cause drive shaft to move outwardly in direction  73  in response to counterclockwise rotation of adjustor  22  (and drive shaft  62 ) about axis  72 . It is within the scope of this disclosure to use other suitable means to move drive shaft  62  in directions  71 ,  73  relative to overflow container  26 . 
     The biasing or closure force applied to pressure-relief valve member  50  by biasing spring  52  is increased (i.e., greatened) when drive shaft  62  is moved in direction  71  owing to greater compression of biasing spring  52   a  suggested, for example, in  FIG. 3 . In contrast, the biasing or closure force applied to pressure-relief member  50  by biasing spring  52  is decreased (i.e., lessened) when drive shaft  26  is moved in direction  73  owing to lesser compression (i.e., decompression) of biasing spring  52  as suggested, for example, in  FIG. 2 . 
     In the illustrated embodiment, as suggested in  FIG. 2 , pressure-relief valve member  50  is formed to include a central aperture  80 . Pressure-relief valve member  50  includes a seal ring  81 , an outer seal plate  82 , an inner seal plate  83  coupled to outer seal plate  82  to retain seal ring  81  therebetween, and a spring mount  84  coupled to outer seal plate  82  and to inner end  61  of biasing spring  52 . 
     Coolant tank  24  includes an outer wall  25  formed to include passageway  28  therein in the illustrated embodiment. Overflow tank  26  is coupled to coolant tank  24  to cause interior region  30  of coolant tank  24  to lie on a first side  25   a  of outer wall  25  and interior region  38  of overflow tank  26  to lie on an opposite second side  25   b  of outer wall  25   a  suggested in  FIG. 2 . 
     Pressure-relief valve member  50  is moved by biasing spring  52  and compression controller  20  normally to engage second surface  25   b  of outer wall  25  of coolant tank  24  normally to close passageway  28  as shown, for example, in  FIG. 2 . During “high-pressure” conditions in interior region  30  of coolant tank  24  pressure-relief valve member  50  is moved away from a valve seat established on second surface  25   b  of outer wall  25  of coolant tank  24  to vent vapor  33  through passageway  28  into interior region  38  of overflow tank  26  as shown, for example, in  FIG. 4 . 
     In the illustrated embodiment, vacuum-relief valve member  54  includes a seal member  85 , seal plate  86 , and post  87  coupled to seal plate  86 , as shown, for example, in  FIG. 2 . Biasing spring  56  is coupled to post  87  and to outer seal plate  82  normally to move seal member  85  to a position closing central aperture  80  formed in pressure-relief valve member  50  as shown, for example, in  FIGS. 2–4 . Biasing spring  56  is located in interior region  38  of overflow tank  26  and inside a space bounded by biasing spring  52 . 
     During “vacuum” conditions in interior region  30  of coolant tank  24 , vacuum-relief member  54  will be drawn in direction  71  into interior region  30  away from an annular valve seat  88  formed on inner seal plate  83  to open central aperture  80  formed in pressure-relief valve member  50  as shown, for example, in  FIG. 5 . This action allows air  89  or other liquid and/or gas to flow through central aperture  80  and passageway  28  from interior region  38  of overflow tank  26  into interior region  30  of coolant tank  24  as shown in  FIG. 5 . 
     In the illustrated embodiment, pressure-relief valve member  50 , biasing spring  52 , and at least a portion of compression controller  20  are located in interior region  38  of overflow tank  26 . As suggested in  FIG. 2 , an outer end  60  of biasing spring  52  engages compression controller  20  and an inner end  61  of biasing spring  52  engages pressure-relief valve member  50 . 
     As suggested in  FIGS. 2 and 3 , compression controller  20  engages overflow tank  26  to permit limited movement of compression controller  20  back and forth along axis  72  associated with coiled compression spring  52 . Movement of compression controller  20  along axis  72  in a first direction  71  toward coolant tank  24  compresses coiled compression spring  52 . Movement of compression controller  20  along axis  72  in an opposite second direction  73  away from coolant tank  24  decompresses coiled compression spring  52 . 
     In the illustrated embodiment, overflow tank  26  includes internal threads  64  and compression controller  20  includes external threads  63 . External threads  63  are configured to mate with internal threads  64  to support compression controller  20  for rotation about and linear motion along axis  72  relative to overflow tank  26 . Such rotation and motion in a first direction compresses biasing spring  52  so as to greaten the biasing or closure force applied by biasing spring  52  to maintain pressure-relief valve member  50  in the closed position. Such rotation and motion in a second direction decompresses biasing spring  52  so as to lessen the biasing or closure force applied by biasing spring  52  to maintain pressure-relief valve member  50  in the closed position. 
     In the illustrated embodiment, compression controller  20  includes a drive shaft  62  formed to include external threads  63 . Drive shaft  62  is arranged to extend through bore  64  formed in overflow tank  26  and defined by internal threads  65 . As suggested, for example, in  FIG. 2 , top wall  70  of overflow tank  26  is formed to include aperture  68  and overflow tank  26  includes a ring  66  mounted in aperture  68  and formed to include internal threads  65  and bore  64 . 
     In use, compression controller  20  is engaged to overflow tank  26  to provide means for varying the biasing (closure) force applied by biasing spring  52  to either lessen or greaten the biasing force applied by biasing spring  52  to maintain pressure-relief valve member  50  in the closed position. Thus, a relatively low pressure of fluid in coolant tank  24  is sufficient to move pressure-relief valve member  50  against the biasing (closure) force of biasing spring  52  to assume an opened position allowing flow of fluid from coolant tank  24  into overflow tank  26  when compression controller  20  is operated to “decompress” biasing spring  52 . In contrast, a relatively high pressure of fluid in coolant tank  24  must be extant to move pressure-relief valve member  50  against the biasing (closure) force of biasing spring  52  to assume the opened position when compression controller  20  is operated to “compress” biasing spring  52 . 
     Reference is made to U.S. Pat. Nos. 5,114,035 and 6,276,312, which references are hereby incorporated by reference herein. These references disclose engine cooling systems and radiator caps. It is within the scope of this disclosure to couple pressure regulator  14  to a radiator cap. 
     A non-adjustable degas bottle  10 ′ in accordance with another embodiment of the disclosure is shown, for example, in  FIG. 6 . In this embodiment, pressure-relief valve member  50  and biasing spring  52  are included in pressure regulator  14 ′ and located in interior region  38  of overflow tank  26 . A stand-off such as, for example, sleeve  90  is coupled to top wall  70  of overflow tank  26  and arranged to extend into interior region  38  to engage spring mount  58  so that biasing spring  52  is compressed to assume a predetermined state. Such a state can be determined during manufacture of degas bottle  10 ′ by selecting a predetermined length  92  of sleeve  90 . Vacuum-relief valve  18  is also included in pressure regulator  14 ′.