Patent Document

FIELD OF THE INVENTION 
   The present invention relates to an improved flow volume limiting device for discontinuing flow when a metered flow volume occurs. 
   DESCRIPTION OF THE PRIOR ART 
   There are applications where it is desirable to prevent liquid flow from exceeding a maximum flow volume. For one example, such a device can be used to supply water to an appliance such as a washing machine and prevent flooding in the event of failure of a component such as a flexible water supply hose. Many devices are known for delivering a metered volume of liquid in a cycle of operation. Most known devices require manual reset prior to each cycle of operation, and are not suitable for automatically limiting the volume of flow to an appliance. 
   U.S. Pat. No. 998,089 discloses a fluid meter with a valve that discontinues flow when a predetermined volume of flow has occurred. The predetermined volume is set by manually rotating an arm from a home position, and simultaneously a opening a flow valve against the force of a spring. A vane wheel is rotated by flow through the meter, and gears rotate the arm back toward the home position. When a predetermined volume of flow occurs, the indicator arm returns to the home position to release a catch lever and the spring closes the valve. 
   In general, the flow volume limiting device  20  includes a housing  34  containing a volume measuring assembly  36  for measuring the volume of liquid that flows through the device  20  and a flow interrupt assembly  38  including a valve assembly  40  for discontinuing flow if the measured flow reaches a maximum amount. An adjustment member or collar  42  is used to select a desired maximum volume. A clutch assembly  44  interconnects the volume measuring assembly  36  to the flow interrupt assembly  38  for simultaneous movement in response to measured flow, or alternatively disconnects the volume measuring assembly  36  from the flow interrupt assembly  38  for reset of the components of the device  20  to their initial condition. 
   U.S. Pat. No. 3,497,106 discloses a flowmeter with a knob that is rotated to select an amount of liquid for delivery. Liquid flow rotates an impeller and drive gears rotate a cam. When the selected volume of liquid is delivered, a notch on the cam aligns with a push rod and a spring biased valve closes to discontinue liquid flow. U.S. Pat. No. 3,810,562 discloses a flowmeter similar in some respects to the flowmeter of U.S. Pat. No. 3,497,106, and further including a clutch means for rendering the rotary cam inoperative so that liquid can be delivered without metering. A pointer is rotated and a stationary cam lifts a shaft and the rotary dam to disengage it from the gear drive. 
   U.S. Pat. No. 3,902,201 discloses a plumbing valve for delivering a metered volume of water to a toilet flush tank. This device does not require manual reset prior to an operating cycle, but does require manual operation to initiate a liquid delivery cycle. At the beginning of a flushing operation, a manually movable lever moves a follower to open a valve. The valve is briefly latched open by a swing lever. Flow rotates a turbine that operates though a reducer to rotate a cam until the follower aligns with a notch in the cam and the valve closes. 
   U.S. Pat. No. 4,023,708 discloses a safety device for preventing flooding by providing a measured volume of flow to a washing machine. This device requires no manual setting or resetting. Flow though the device rotates a turbine wheel that operates through gears to rotate a valve member having a hub with teeth. After a predetermined flow volume, the teeth align with notches and a spring closes the valve. When pressure is discontinued, the valve spring moves the valve and hub against an inclined surface of a cap, rotating the valve and hub back to their initial positions. To permit rotation of the valve and hub relative to the gears and turbine, the gears are mechanically unmeshed, and must be reengaged before the next delivery cycle. 
   SUMMARY OF THE INVENTION 
   A primary object of the present invention is to provide an improved device for limiting liquid flow to a maximum metered volume. Other objects are to provide a flow volume limiting device that operates and resets automatically; to provide a device that includes an elastomeric friction clutch providing a simple and reliable way to couple or uncouple the rotary drive connection between a flow measuring system and a valve control member; to provide a device with a simple and reliable valve controlling arrangement including a valve piston with a valve seat cooperating with a valve disk; to provide a device with a simple construction resulting from use of a disk as both a valve member and as a component of the clutch; and to provide a simple and reliable automatic and adjustable flow volume limiting device overcoming problems encountered with known flow volume limiting devices. 
   In brief, in accordance with the present invention, there is provided a flow volume limiting device for use in a liquid supply system. The device includes a housing defining a flow path. A flow responsive piston slides along the flow path in downstream and upstream directions and a spring biases the piston in the upstream direction. A flow passage through the piston is surrounded by a valve seat on the piston. A valve member cooperates with the valve seat to permit and prevent flow through the flow passage. A control element is connected to the valve member and a stop is engaged by the control member to stop downstream movement of the control member and valve during downstream movement of the piston to separate the valve member from the valve seat. A flow volume measuring assembly has an output shaft rotating in response to flow in the flow path. A friction clutch interconnects the flow measuring assembly and the control element for rotating the control element in a first direction when the clutch is engaged. The friction clutch is exposed to a liquid pressure differential in the flow path for engaging the clutch when flow is present and disengaging the clutch when flow is absent. A recess in the control element registers with the stop permitting downstream movement of the valve member against the valve seat in response to rotation of the control element to an interrupt position. A reset cam is engaged by the control element for rotating the control element in a second direction to an initial position in response to upstream movement of the control element 

   
     BRIEF DESCRIPTION OF THE DRAWING 
     The present invention together with the above and other objects and advantages may best be understood from the following detailed description of the preferred embodiment of the invention illustrated in the drawings, wherein: 
       FIG. 1  is a side and top isometric view of a flow volume limiting device constructed in accordance with the present invention, connected in a water system shown schematically in a block diagram; 
       FIG. 2  is a side and bottom exploded isometric view of the flow volume limiting device; 
       FIG. 3  is an enlarged view of a portion of  FIG. 2  with components of the flow volume limiting device seen in cross section; 
       FIG. 4  is an enlarged view, in cross section taken along the longitudinal axis, of the flow volume limiting device in a standby, no flow condition; 
       FIG. 5  is a view like  FIG. 4  showing the device as flow through the device is beginning; 
       FIG. 6  is a view like  FIG. 4  showing the device with continuing metered flow; 
       FIG. 7  is a view like  FIG. 4  showing the device preventing further flow after a metered flow volume has occurred; 
       FIG. 8  is a view like  FIG. 4  showing the device being reset; 
       FIG. 9  is fragmentary, enlarged view of part of the valve seat of the piston of the valve assembly of the device; and 
       FIG. 10  is an enlarged fragmentary view, partly in cross section of the mounting of the valve and clutch disk of the device. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   Having reference now to the drawing, and initially to  FIG. 1 , there is illustrated a flow volume limiting device generally designated as  20  and constructed in accordance with the principles of the present invention. The device  20  may be employed in applications where it is desired to limit the measured volume of liquid flow to a maximum value. 
   In  FIG. 1 , the device  20  is connected in a water supply system  22  of a water utilizing device or appliance  24  such as a clothes washing machine. In this application, a supply valve  26  such as a wall faucet normally continuously connects water from a pressurized source  28 , such as a household water supply, through a conduit such as a flexible hose  30  to a solenoid operated inlet control valve  32  of the washing machine  24 . In the absence of the device  20 , if there were a failure such as a rupture of hose  30  or a malfunction of the control valve  32 , uncontrolled flow and flooding could occur. For simplicity, only a single water supply connection to the appliance  24  is shown. However, a typical clothes washer installation includes both hot and cold water supply connections, and both of these may be equipped with a device  20 . 
   The flow volume limiting device  20  of the invention prevents uncontrolled flow and flooding by metering the volume of water supplied to the appliance  24  and discontinuing flow if a maximum flow volume occurs. The maximum flow volume is selected to have a value sufficient for normal operation of the appliance  24  so that the operation of the appliance  24  is not disturbed unless there is a failure in the water system  22 . The device  20  performs the metering and flow interrupt functions, and also resets itself, automatically without the need for manual control or inputs. 
   In general, the flow volume limiting device  20  includes a housing  34  containing a volume measuring assembly  36  for measuring the volume of liquid that flows through the device  20  and a flow interrupt assembly  38  including a valve assembly  40  for discontinuing flow if the measured flow reaches a maximum amount. An adjustment member or collar  42  is used to select a desired maximum volume. A clutch assembly  44  interconnects the volume measuring assembly  36  to the flow interrupt assembly  38  for simultaneous movement in response to measured flow, or alternatively disconnects the volume measuring assembly  36  from the flow interrupt assembly  38  for reset of the components of the device  20  to their initial condition. 
   The housing  34  includes a base  46  and a cap  48  threaded onto the base  46  to define an internal flow cavity  50  extending between an inlet filling  52  in the cap  48  and an outlet fitting  54  in the base  46 . A seal  56  seals the cavity  50 . For use in the water system  22  of  FIG. 1 , the inlet fitting  52  is a female threaded fitting adapted to mate with the male threaded fitting of a conventional water supply faucet  26 . The outlet fitting  54  is a male threaded fitting adapted to be connected to the female threaded fitting of a conventional hot or cold water supply hose  30 . For other applications of the device  20 , other types of inlet and outlet fittings can be used. 
   The flow volume measuring assembly generally designated as  36  includes a cup shaped inlet flow guide  58  received within the cap  36 . Guide  58  includes peripheral flow ports  60  that direct inlet flow from the inlet  52  toward vanes  62  of a turbine wheel  64 . Preferably the vanes  62  are oriented parallel to the central longitudinal axis of the device  20  and the flow ports  60  extend through the wall of the guide  58  in a non axial direction so that they impart a rotational or spiral swirling motion to the flow of water for turning the turbine wheel  64 . This reduces axial thrust, friction and wear and increases component life. Turbine wheel rotation is relatively fast and is directly proportional to flow volume through the device  20 . A speed reduction gear assembly  66  provides a slow speed output rotation to an output shaft  68  of the gear assembly  66 . For example, turbine wheel rotation of about 1,800 RPM may be reduced by the gear assembly to a single rotation of the output shaft  68 . Peripheral rims of the flow guide  58  and the gear assembly  66  are clamped against the seal  56  between the base  46  and cap  48 . 
   The clutch assembly generally designated as  44  releaseably connects the flow volume measuring assembly  36  including the turbine wheel  64  and the gear assembly  66  to the flow interrupt assembly generally designated as  38 . A drive shaft  70  is connected by splines to the gear assembly output shaft  68  so that the drive shaft  70  is axially movable relative to and rotates together with the output shaft  68 . The lower end of the drive shaft  70  carries a flexible, resilient clutch member  72  made of rubber or a similar elastomeric material. 
   The clutch member  72  cooperates with a valve and clutch disk  74  to either permit or prevent rotation of the disk  74  relative to the clutch member  72 . In the clutch engaged condition seen in  FIGS. 5 and 6 , the clutch assembly  44  is engaged and the disk  74  cannot slip or rotate relative to the clutch member  72 . In this condition, a rotary connection is established between the flow measuring assembly  36  and the flow interrupt assembly  38 . In the clutch disengaged condition seen in  FIGS. 4 ,  7  and  8 , the clutch assembly  44  is released and the disk  74  can slip or rotate relative to the clutch member  72 . In this condition, the flow interrupt assembly  38  is disconnected or uncoupled from the flow volume measuring assembly  36 . 
   In addition to the valve and clutch disk  74 , the valve assembly  40  includes a circular valve seat  76  surrounding a circular flow port or passage  78  formed in a piston  80 . When the disk  74  is in engagement with the seat  76  ( FIGS. 4 ,  5  and  8 ), the valve assembly  40  is closed and there is no substantial liquid flow through the passage  78 . When the disk  74  is spaced from the seat  76 , the valve assembly  40  is open and liquid can flow through the passage  78  from the inlet  52  to the outlet  54 . As seen in  FIG. 9 , the valve seat  76  is provided with a discontinuity in the form of a small notch  81 . The purpose of the notch  81  is to permit a small, restricted bypass flow across the valve assembly  40  when the valve assembly is closed with the disk  74  in engagement with the valve seat  76 . 
   The valve and clutch disk  74  is attached to the top upper end of a drive rod  82  of the flow interrupt assembly  38 . As seen in  FIG. 10 , the upper end of the drive rod  82  is formed with an opposed pair of flats  84  defining opposed shoulders  86 . The disk  74  has a complementary partly circular shape with opposed flats  88  and the disk  74  is supported above the shoulders  86 . A spring clip  90  snaps into a groove  92  in the rod  82  to retain the disk  74 . A clearance  94  between the disk  74  and the rod  82  permits a small restricted flow between the region under the clutch member  72  and the output port  54 . 
   The piston  80  is supported within the housing  34  for vertical movement between an uppermost position seen in  FIG. 4  and a lowermost operating position seen approximately in  FIG. 7 . A seal  96  permits this sliding movement while preventing flow of liquid around the piston  80 . A coil piston return spring  98  continuously biases the piston  80  toward its upper position with a small force of a few pounds. 
   The flow interrupt assembly  38  includes a control, or stop and cam, member  100  fixed to the bottom of the drive rod  82 . The member  100  is guided for rotation and for vertical sliding movement in a guide sleeve  102  formed in the lower portion of the base  46  of the housing  34 . In most rotational positions of the control member  100 , the member  100  bottoms against the top of a stop rib  104  formed within the guide sleeve  102  as seen in  FIGS. 5 and 6 . In one rotational position of the control member  100 , referred to herein as the flow interrupt position, a slot  106  in the control member  100  is aligned with the stop rib  104 , and the control member  100  is able to move further downward to the position seen in  FIGS. 4 and 7 . 
   A cam system  110  resets the flow interrupt assembly  38  after flow through the device  20 . The cam system  110  includes a first, upwardly directed reset cam  112  in the form of an inclined cam surface at the top of the control member  100 . The adjustment member  42  includes a central hub portion  114  having an annular recess  116  receiving the upper end of the guide sleeve  102 . The hub portion  114  includes a second, downwardly directed reset cam  118 . The control member  100  can move upward, resulting in engagement of the first cam  112  with the second reset cam  118 . This engagement can cause rotation of the control member to an initial rotational position following flow through the device  20 . The flow interrupt assembly  38  is reset with no flow through the device  20  because the notch or discontinuity  81  allows restricted flow across the valve seat  76 . 
   The adjustment member  42  is rotatably mounted in the lower portion of the base  46  of the housing  34 . A sliding fit of the sleeve portion  102  in the annular recess  116  journals the adjustment member for rotation. Windows  120  in the base  46  of the housing  34  permit the user to grasp and rotate the adjustment member  42  in order to position the reset cam  118  and select a maximum flow volume. Seals  122  and  124  prevent leakage of liquid through windows  120 . A stop  126  is formed within the lower portion of the base  46  ( FIGS. 4-8 ). The adjustment member  42  includes an internally directed stop projection  128 , and engagement of the projection  128  with the stop  126  limits rotation of the adjustment member to slightly less than one full revolution. 
   Operation of the flow volume limiting device  20  is now described. To prepare the device for use, the user rotates the adjustment member  42  to select a maximum flow volume. Rotation of the adjustment member  42  determines the maximum rotational offset of the slot  106  of the control member  100  from the stop rib  104 . This establishes the maximum rotation of the shaft  70 , engaged clutch assembly  44 , rod  82  and control member  100  permitted before the slot  106  in the control member  100  is aligned with the stop rib  104 , and the control member  100  is able to move downward to the position seen in  FIGS. 4 and 7 . Because this rotation is determined by measurement of flow by the volume measuring assembly  36 , this in turn sets a maximum flow volume permitted in any cycle of operation by the device  20 . 
   For example, a typical water utilizing appliance such as a clothes washer may consume in the range of five to twenty gallons of water in each water supply cycle, such as the beginning of a wash cycle or rinse cycle. The device  20  preferably has a maximum volume adjustment range from a minimum of a few gallons to a maximum of, for example, fifty gallons. The user may select a maximum volume that slightly exceeds the requirement of a particular appliance. The surface of the adjustment member  42  may be provided with visible graduations or other indicia of the set volume. The device is connected into a water supply system such as the system  22  seen in  FIG. 1 , and the supply valve  26  is opened in preparation for operation of the appliance  24 . 
     FIG. 4  illustrates the flow volume limiting device  20  in an initial, standby condition before the start of a water supply cycle. In this condition, the supply valve  26  of the water supply system  22  is open and the solenoid operated appliance valve  32  is closed, and there is no flow through the device  20  and no pressure differential between the inlet  52  and outlet  54 . The piston return spring  98  holds the piston  80  in its upper position. The clutch assembly  44  is disengaged. The valve assembly  40  is closed. The control member  100 , together with the attached rod  82  and valve and clutch disk  74 , are in their initial position of maximum adjusted rotational displacement of the slot  106  from the stop rib  104 . 
   When a water utilization cycle of the appliance  24  begins, the control valve  32  opens and flow through the device  20  is initiated. As seen in  FIG. 5 , a differential pressure force of a few pounds is imposed across the piston  80  by the force of the piston return spring  98  and the effect of initial inlet pressure. One result of this force is that the clutch assembly  44  is engaged to rotationally lock the volume measuring assembly  36  to the flow interrupt assembly  38 . The flexible, resilient, elastomeric clutch member  72  initially has a concave, shallow cup shape ( FIG. 4 ) defining a space  130  between the clutch member  72  and the disk  74 . When the clutch assembly is subjected to a differential pressure force as seen in  FIG. 5 , liquid is expelled toward the outlet  54  from the space  130  through the restricted flow clearance  94  ( FIG. 10 ) and the clutch member  72  is deformed and clamped firmly in flat, face to face engagement against the disk  74 . With the clutch assembly engaged, the control member  100  rotates in response to liquid volume measured by the volume measuring assembly  36 . 
   Another result of the initial differential pressure force is that the valve and clutch disk  74  is held against the valve seat  76 , and the piston  80  moves downward, along with the splined drive shaft  70 , the clutch assembly  44 , the valve assembly  40  and the control member  100 . This downward movement at the initiation of a water supply cycle continues until the control member  100  contacts the stop rib  104 . This contact is beginning to occur in  FIG. 5 . 
   As seen in  FIG. 6 , when the control member  100  contacts the stop rib  104 , downward movement of the splined drive shaft  70 , the clutch assembly  44 , the valve assembly  40  and the control member  100  ceases, while the piston  80  continues to move downward toward its lowermost position. The valve seat  76  moves away from the valve and clutch disk  74 , and liquid flows through the valve flow port  78 . The space between the disk  74  and the valve seat  76  forms a flow throttling gap, and a pressure differential of a few pounds across the throttling gap results from the force applied to the piston  80  by the piston return spring  98 . The clutch assembly  44  is maintained in the clamed, engaged condition. 
   As flow continues, the engaged clutch assembly  44  causes the flow measuring assembly  38  to rotate the control member  100  from its initial position toward the maximum volume, flow interrupt position where the slot  106  registers with the stop rib  104 . In normal operation with no failure in the water system  22 , the appliance control valve  32  closes before the maximum flow volume occurs. When flow is discontinued, by the valve  32  or otherwise, the device  20  including the flow interrupt assembly  38  is reset to the initial condition. 
   In the absence of flow at the end of a normal water supply cycle, the clutch assembly  44  is disengaged as the resilient clutch member  72  returns to its original shape and the entry of liquid through the clearance  94  reestablishes the space  130 . Any remaining residual frictional engagement between the periphery of the clutch member  72  and disk  74  is minimized by use of a low friction material such as an acetal or Polybutylene Terephthalate (PBT) for the disk  74 . As a result, the rod  82 , disk  74  and the control member  100  are able to rotate relative to the clutch member  72  and shaft  70 . 
   In addition, at the end of a normal water supply cycle, the restricted flow through the notch or discontinuity  81  in the valve seat  76  permits the piston return spring  98  to gradually lift the piston  80  from its lower position of  FIG. 6 . As seen in  FIG. 8 , the cam surface  112  of the control member  100  engages the reset cam surface  118  of the adjustment member  42 . The resulting cam action rotates the control member  100  and returns it to its initial rotational position, ready for a subsequent water supply cycle. This reset rotation is possible because the clutch assembly  44  is disengaged. After a short period of time, for example a few seconds, the piston is lifted to the initial position of  FIG. 4  and the device  20  is reset to the initial condition, ready for the next water supply cycle. 
   In the event of a malfunction in the water system  22 , such as rupture of the water supply hose  30 , the volume of flow through the flow volume limiting device  20  may reach the maximum volume amount set by positioning of the adjustment member  42 . When the maximum flow volume is reached, the volume measuring assembly  36  rotates the control member  100  to the flow interrupt position seen in  FIG. 7  wherein the slot  106  in the member  100  is in alignment with the stop rib  104 . The control member  100  moves down, along with the rod  82  and the valve and clutch disk  74 . The disk  74  engages the valve seat  76  to interrupt flow through the device  20  and prevent flooding and damage due to the water supply malfunction. The piston  80  moves down to the position seen in  FIG. 7  where a secondary seating area  132  atop the central hub portion  114  engages a bevel valve seat  134  surrounding the flow port  78 . This provides a final seal preventing flow through the device  20 . The clutch assembly  44  is disengaged as the space  130  expands because the differential pressure across the notch discontinuity  81  is dissipated. 
   Following a flow interrupt, the device  20  remains in the flow interrupt condition seen in  FIG. 7  for as long as the supply valve  26  continues to apply substantial pressure to the inlet  52 . The user may close the valve  26  and correct the system malfunction. When valve  26  is closed, the piston return spring raises the piston  82  and the device  20  including the flow interrupt assembly  38  is reset to the initial condition seen in  FIG. 4 . 
   While the present invention has been described with reference to the details of the embodiments of the invention shown in the drawing, these details are not intended to limit the scope of the invention as claimed in the appended claims.

Technology Category: f