Abstract:
A suction inlet valve for fire truck pumpers has a male body portion and a female body portion, the portions defining a chamber therein. A cone-shaped valve element is connected to a valve stem which has a cam body thereon with a cam slot therein. The cam slot receives a projection from an operating shaft which projects out of the housing. The operating shaft has an operating handle thereon which is exposed to the environment and conducts heat from the chamber. If there is water in the chamber, there is an increased chance of water in the cam slot freezing disabling operation of the valve. To drain water away from the cam slot, a drain is provided in the male body portion for draining water from the chamber.

Description:
FIELD OF THE INVENTION  
       [0001]     This invention relates to suction inlet valves for fire truck pumpers. More particularly, this invention relates to suction inlet valves for fire truck pumpers usable in both hydrant and drafting operations.  
       BACKGROUND ART  
       [0002]     Fire companies utilize pumper trucks to increase the pressure of hydrant water flowing through fire hoses and to pressurized water from drafting tanks. Pumpers draw water through suction valves from sources such as portable water tanks or fire hydrants.  
         [0003]     Illustrative of widely used suction inlet valve are the Pre-Con valves available from Hydra-Shield Manufacturing, Inc. of Irving, Tex., covered by U.S. Pat. No. 5,178,183. The Pre-Con valve is designed to operate as an automatic flow control valve which eliminates the need for manual adjustments in reaction to water flow. In hydrant operations, the Pre-Con valve automatically opens in proportion to the flow demand and is capable of automatically balancing flow between multiple water sources. The Pre-Con valve&#39;s automatic check valve action also minimizes water hammer. When drafting from a source of water, such as a portable water tank, the check valve action of the Pre-Con valve holds prime water when flow is stopped and allows switching to a booster tank and back to drafting without flow interruption. The Pre-Con valve is an improvement over butterfly valves which it has replaced in many situations.  
         [0004]     Pre-Con valves have continued to improve over the years with current configurations having follower-in-slot cam operators rather than external profile cam operators. It has been found that these current configurations have a tendency to freeze in cold weather which can render the valve and associated equipment at least temporarily useless in cold weather.  
       SUMMARY OF THE INVENTION  
       [0005]     The present invention is directed to an inlet suction valve use with pumper fire trucks. The inlet suction valve comprises a valve housing having a male body portion defining a first cavity and a female body portion defining a second cavity, the body portions are joined with the cavities forming a chamber. A first coupling is provided on the male body portion for coupling with a source of water and a second coupling is provided on the female body member for coupling with a pumper boaster tank on the fire truck. A valve element is disposed in the first cavity and is seated against a valve seat located adjacent to the first coupling. A valve support with an axial hole therethrough is disposed between the first and second cavities of the male and female bodies. The valve support has openings therethrough allowing water to flow freely from the first cavity to the second cavity. A valve stem is connected to the valve element and extends back through the first cavity and the axial hole in the valve support to the second cavity. A cam block is located on the calve stem and has a slot extending therein laterally with respect to the axis of the valve stem. A valve operating shaft extends from outside the housing to the cam block, the valve operating shaft having a crank arm extending laterally therefrom with a projection thereon that is spaced from the axis of the valve operating shaft. The projection is received in the slot in the cam body. A valved drain extends through the female valve body and in to the second cavity to drain water away from the cam body to avoid frozen water from clogging the slot and preventing operation of the valve.  
         [0006]     In a further aspect of the invention, an operating handle projects from the operating shaft.  
         [0007]     In still a further aspect of the invention, the operating handle is a lever and a lateral hole formed through a portion of the support to receive the operating shaft therethrough. The inlet suction valve is made substantially of metal and lubricant disposed around the valve stem and operating shaft.  
         [0008]     In still a further aspect of the invention, a valved vent outlet is disposed on the male body member and is connected by a bore through the male body member to the first coupling at a location in front of the valve element. The valved vent outlet on the male body member is located at the bottom of the female housing directly adjacent to the water drain on the female body member. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]     Various other features and attendant advantages of the present invention will be more fully appreciated as the same becomes understood when considered in conjunction with the accompanying drawings, in which like reference characters designate the same or similar parts throughout the several views, and wherein:  
         [0010]      FIG. 1  is a schematic view showing a suction inlet valve of the instant invention drafting water from a portable water tank;  
         [0011]      FIG. 2  is a schematic illustration showing use of a suction valve according to the instant invention being used with a fire hydrant;  
         [0012]      FIG. 3  is a side elevation of the suction inlet valve according to the present invention;  
         [0013]      FIG. 4  is a top elevation taken along lines  4 - 4  of  FIG. 3 , and  
         [0014]      FIG. 5  is an exploded view of the suction inlet valve of  FIGS. 3 and 4 . 
     
    
     DETAILED DESCRIPTION  
       [0015]     Referring now to  FIG. 1 , a suction inlet valve designated by the numeral  10  and configured in accordance with the principles of the instant invention, is disposed at the end of a suction pipe  12  used in a drafting operation. The suction pipe  12  is connected by a line  14  to a pumper booster tank  16  within a pumper firetruck (not shown). At its inlet end the suction valve is connected by a suction hose  18  to a source of water, such as a portable water tank  20 . A pump discharge manifold  22  is connected to fire hoses  24  at either or both ends. Upon opening a booster tank valve  26 , water is forced at elevated pressure through the fire hoses  24 .  
         [0016]     After the pump in the firetruck (not shown) is primed and activated, the suction inlet valve  10  automatically opens at about 8 to 10 inches of vacuum if set in an automatic mode. Normally, the suction inlet valve  10  automatically opens or closes in proportion to the volume of water flow.  
         [0017]     If the water level in the tank  20  gets too low, the booster valve  26  is opened to decrease the flow resistance from the booster tank  16  allowing the suction inlet valve  10  to automatically close and thereby hold prime water in the suction hose  18 . When the water level in the portable tank  20  is restored, the booster valve is closed so as to create a vacuum in the pump which automatically opens the suction inlet valve  10 .  
         [0018]     If it is desired to utilize the pumper booster tank  16  as an emergency reservoir, the suction inlet valve  10  allows the operator to switch from drafting from the portable water tank  20  to drafting from the booster tank  16  without disrupting water flow through the fire hoses  24 . In the event that all discharge lines  24  are shut off, the suction inlet valve  10  automatically closes to hold prime in the suction hose  18 .  
         [0019]     From the above discussion, it is seen that the suction inlet valve  10  is critical to proper operation of a pumper firetruck. In order to tune the system to particular situations, it is advantageous to have the capability of manually adjusting the amount that suction inlet valve  10  opens.  
         [0020]     Referring now to  FIG. 2  where similar elements have the same reference numerals, a pumper truck is schematically shown working from a fire hydrant  28 . When the hydrant  28  is turned on, water pressure automatically opens the suction inlet valve  10  if the valve has been manually adjusted for automatic operation. The suction inlet valve  10  opens at approximately 5 psi and will open in proportion to the flow demand. When flow is shut off through the pump discharge line  22 , the suction inlet valve  10  automatically closes and, due to its novel configuration, reduces the water hammer effect in the suction hose  18  and fire hydrant  28 . If it is desired to provide water from an auxiliary source, an additional inlet suction valve  10 ′ can be connected to the opposite end of pump suction line  12 .  
         [0021]     When working from a fire hydrant  28 , it is advantageous to provide for automatic operation of the suction inlet valve  10 , which automatic operation can be adjusted and if necessary, overridden. This is especially so when there are pair of suction inlet valves  10  connected to the same pump suction line  12 . As will be explained in detail hereinafter, the suction inlet valve  10  has a control handle which determines the setting of automatic flow control pumper suction inlets. In its automatic mode, the valve  10  automatically opens or closes in response to flow demand. As more discharge lines are opened from a pumper truck, or if nozzle flows increase, the valve  10  automatically opens to the limit of the control handle setting. If flow is reduced, the valve  10  automatically closes proportionally and when flow is stopped, the valve closes completely. Automatic adjustment and operation is particularly important in reducing the effects of water hammer caused by abruptly shutting off a nozzle attached to a fire hose  24 .  
         [0022]     The valve  10  also functions as a one way flow valve. During fire hydrant operations ( FIG. 2 ), high pressure water sources which occur during operations such as pump relay operations, are prevented by the valves  10  from overriding low pressure water sources. Moreover, multiple inlets with the valves  10  can be used to balance the water flow from several different sources. When used in the drafting mode of  FIG. 1 , the automatic check valve action of valve  10  holds prime water in the suction hose  18  when flow is stopped. This is very important because the system does not have to reprimed to restart the pumping operation.  
         [0023]     With the foregoing background in mind, a particular structure of the valve  10  suitable for providing automatic operation which is manually adjustable is set forth in  FIGS. 3-5 . Referring first to  FIG. 3 , it is seen that the valve  10  has an operating lever  29  which selectively sets the mode to a fully “closed” mode, a fully “open” mode or a setting selected therebetween. The valve  10  opens automatically at any setting other than fully closed mode, however, the volume of flow is reduced at settings other than the fully open mode.  
         [0024]     Referring now also to  FIGS. 4 and 5  as well as  FIG. 3 , the vlave  10  comprises a male body portion  30  which has a threaded neck  32  onto which is threaded a suction hose such as the suction hose  18  of  FIGS. 1 and 2 . The neck  32  has a mouth  34  therein into which water flows. The water may be under pressure, such as the pressure applied from the fire hydrant  28  of  FIG. 2 , or may be unpressurized if provided by a source such as the portable water tank  20  of  FIG. 1 . The male body member  30  has a first cavity  36  with an annular substantially flat area  38  which joins the cavity  36  to the mouth  34 . As is seen in  FIG. 5 , the male body member  30  may have alternate configurations  30 ′ and  30 ″ with Storz couplings  39 ′ and  39 ″, respectively.  
         [0025]     Attached to the male valve body  30 , is a female valve body  48  with a second cavity  49  therein. A plurality of bolts  50  are received through threaded bores  52  in an annular flange  54  around the periphery of the female body member  48 . The female body member  48  has a neck  56  which has rotatably mounted thereon a threaded collar  60  which has internal threads  64 . The threads  64  of the portable collar  60  threadably receive male fittings on the suction pipes  12  of  FIGS. 1 and 2 . In order to ensure a leakproof seal, a gasket  66  abuts the end of the neck  56  and is loosely received in an annular groove within the collar  60 . Since the gasket  66  may be subject to considerable wear, it is readily replaceable.  
         [0026]     The cavity  36  of the male valve body  30  and the cavity  49  of the female valve body  48  cooperate to define a chamber  72 . Projecting radially inward into the chamber  72  from the female valve body  48  is a support ring  74  that includes three struts  75 ,  76  and  77  extending inwardly from an annular flange  79  that has an annular lip  80  with holes  81  therethrough. The bolts  50  which extend through the male and female bodies  30  and  48  pass through the holes  81  to retain the support  74  in the chamber  72  while separating the cavities  36  and  49  from one another.  
         [0027]     A valve operating shaft  85  connected to the operating handle  29  extends through a bore  86  in a pedestal  87  on the strut  75 . The valve operating shaft  85  has a crank arm  88  fixed to the bottom end  89  thereof. The crank arm  88  has a pin  90  aligned with an axis  91  spaced from the axis  92  of the valve operating shaft  85 . The pin  90  registers with a slot  95  in a cam body  97 . Preferably, the pin  90  drives a slide block  98  in the slot  95 . The slide block  98  is retained on the pin  90  by a slide block retainer  99 . A valve stem  100  is fixed to the cam body  97  and passes through a bore  102  in the support ring  74 . The valve stem  100  is slidably received in a bore  103  through a cone-shaped valve element  104  and is axially adjusted with a set screw  105  in a threaded portion of the bore  103 . A coil spring  106  extends between the support  74  and the valve element  103  to bias the valve element  103  to a closed position against an annular valve seat  107  on the annular flat portion  38 .  
         [0028]     Upon rotating the shaft  25  in the counter clock wise direction with respect to  FIG. 4 , the pin  90  slides laterally in the slot  95  extending in the cam body  97 . As the pin  90  slides laterally in the slot  95 , the pin draws the valve stem  100  back through the bore  103  against the bias of the spring  106  to pull the cone-shaped valve element  104  away from the annular valve seat  107 .  
         [0029]     There are some situations in which it is advantageous to manually adjust automatic operation of the floating valve element  103  instead of just letting the valve element float.  
         [0030]     The valve  10  is usually left mounted on the fire truck so that there is a tendency for the valve to freeze and become useless in cold weather. This is especially a problem with the aforedescribed configuration where an operating handle  29  is rigidly connected to and operating shaft  85  that is in turn integral with a crank arm  88  and pin  90  because the pin  90  conducts heat rapidly away from the slot  95  in the cam body  97 . Consequently, if there is water in the slot  95 , the water can rapidly freeze in the slot blocking lateral movement of the pin  90  in the slot. If lateral movement of the pin  90  is blocked then the valve element  104  can not be unseated from the valve seat  107  and the valve  10  becomes useless. If the fire truck is racing for several miles through very cold air which flows over the handle  29 , heat is conducted even more rapidly away from the pin  90 . If the pin  90  and slot  95  are immersed in water, water in the slot may freeze thus blocking movement of the pin in the slot even if other retained water in the cavity is not yet frozen.  
         [0031]     In order to prevent frozen water from blocking operation of the valve  10 , a water drain  120  ( FIG. 4 ) with a rotating stop cock valve  121  is positioned at the bottom  122  of the cavity  49  of the female body  48 . Another advantage of draining the chamber is that corrosion on the walls of the chamber and on parts of the cam operating mechanism is reduced. The water drain  120  is positioned in the bottom of the cavity  49  in female body  48  because another fluid vent or drain  130  operated by a stop cock valve  132  is positioned on the bottom  133  of the male body  30 . The fluid vent or drain  130  is connected by a bore  134  to the mouth  34  of the threaded neck  32  and relieves excess pressure on the cone-shaped valve element  104 .  
         [0032]     From the foregoing description, one skilled in the art can easily ascertain the essential characteristics of this invention, and without departing form the spirit and scope thereof, can make various changes and modifications of the invention to adapt it to various usages and conditions.