Abstract:
A drain valve for a vehicle compressed air system, which separates dirt, water, debris and other relatively heavy objects from a compressed air stream. The drain valve includes a sump with a tangential inlet. The tangential inlet creates a vortex within the sump that collects relatively heavy objects at the bottom of the sump and allows the compressed air to exit the drain valve through an outlet port located at the top of the drain valve. A pressure actuated valve and drain port allows for the water to be discharged from the drain valve while retaining the pneumatic signal.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application claims the benefit under 35 U.S.C. §119(e) of U.S. Provisional Application Ser. No. 60/481,288 filed Aug. 25, 2003, the entire disclosure of which is hereby incorporated by reference. 
     
    
     BACKGROUND  
       [0002]     Tractor-trailer trucks are designed to be connected and disconnected. The trailer air brakes are powered and controlled from the tractor through two pneumatic lines—one line supplies air at full system pressure to power the trailer brakes, and the other supplies a pneumatic control signal of varying pressure to indicate when the brakes should be applied or released. The standard connection for these lines between the tractor and trailer is called a gladhand. When the trailer is disconnected from the tractor, the gladhands are generally exposed to the environment, and thus allow water, debris and insects into the system. Water and debris in the system can impact the brake control valves and may even cause them to malfunction.  
         [0003]     Prior solutions to this problem include U.S. Pat. No. 6,358,291 directed to a dual desiccant bed device for capturing incidental water entering the system and subsequently releasing it slowly into dried air from the tractor. U.S. Pat. No. 5,762,094 is directed to a drain mechanism incorporated into the brake relay valve, however, such a mechanism is generally incompatible with anti-lock brake systems. As such, there exists a need to provide a mechanism for capturing and venting any water that is introduced into the trailer air brake system while the gladhands are open.  
       SUMMARY  
       [0004]     The present invention relates to drain valve for a vehicle compressed air system, wherein the drain valve separates dirt, water, debris and other relatively heavy objects from a compressed air stream. The drain valve includes a sump with a tangential inlet. The tangential inlet creates a vortex within the sump that collects relatively heavy objects at the bottom of the sump and allows the compressed air to exit the drain valve through an outlet port located at the top of the drain valve. A drain port allows for the collect material to be discharged from the drain valve.  
     
    
     DRAWING DESCRIPTIONS  
       [0005]     In the accompanying drawings, which are incorporated in and constitute a part of this specification, embodiments of the invention are illustrated, which, together with a general description of the invention given above, and the detailed description given below serve to illustrate the principles of this invention.  
         [0006]      FIG. 1  is a longitudinal cross-sectional view of a drain valve of the present invention with the pressure actuated valve open.  
         [0007]      FIG. 2  is a longitudinal cross-sectional view of a drain valve of the present invention with the pressure actuated valve closed.  
         [0008]      FIG. 3  is a horizontal cross-sectional view of a drain valve of the present invention.  
         [0009]      FIG. 4  is a longitudinal cross-sectional view of a drain valve of the present invention incorporating a fitting located at the opposite end as the drain port.  
         [0010]      FIG. 5  is a schematic view of a compressed air system incorporating the drain valve of the present invention.  
         [0011]      FIG. 6  illustrates a drain valve mounting configuration for vertical storage chassis mounting. 
     
    
     DETAILED DESCRIPTION  
       [0012]     The present invention is directed to a drain valve  10  which includes a sump  20 . The drain valve  10  is located in a compressed air line  22  proximate to the gladhand connector  24  of the trailer, dolly or any other towed vehicle. Optionally, the drain valve  10  can be located on one or more of the tractor compressed air lines or any other location on a vehicle where water needs to be drained from a volume that occasionally depressurized. The sump  20  has a tangential inlet  30  causing cyclone action during brake application which enhances water and particulate separation capability. The air then exits the drain valve  10  through an outlet port  40  and is delivered to down stream brake components, such as, for example, a brake chamber, generally referenced as  25 .  
         [0013]     The drain valve  10  is inserted into the line between the control gladhand and the brake control valves. It is preferable to locate the drain valve  10  near the gladhand and at the first low point in the control line so that water naturally drains into the drain valve  10 . During use of the control line, the air enters the drain valve  10  through the tangential inlet  30  and the cyclonic air effect separates the water and debris from the air. When no control line pressure exists, water and fine particles of debris and dust, drains from the outlet  45  of the sump  20  through a pressure actuated valve  50  and is thereby discharged from the system through drain port  55 .  
         [0014]     During brake application, a pneumatic control signal of about 5 to about 40 pounds per square inch pressure is transmitted from the tractor. This pulse of air blows water and debris that may have entered the gladhand through the control line. Water and debris tangentially enter the generally cylindrical sump  20  and swirl around forming a vortex. Water and debris are forced to the circumference of the sump  20  and clarified air flows to the center of the vortex and out the central outlet port  40  and into the brake valves. Upon release of the brakes, when control pressure drops to zero, or substantially close to zero, retained water is drained to atmosphere, or a collection apparatus (not shown), through the pressure actuated valve  50  and through drain port  55 . It is desirable to keep the sump volume low and the vortex action mild in order to minimize pressure drop through the drain valve  10  and thereby minimize any effect on brake application and release timing. In some embodiments the sump volume is approximately one cubic inch.  
         [0015]      FIG. 1  illustrates an embodiment of the drain valve  10  wherein the inlet  30  is located on the side  60  of the generally cylindrical sump  20 , such that the inlet air enters the sump tangentially. As shown in  FIGS. 1 and 2 , the inlet  30  may be generally circular, such as that formed by drilling, however, other configurations are also possible, such as, for example, a vertical slot tangent to the inner sump cylindrical wall  60 . It should be appreciated that the inlet need not be tangential, but instead can have other known configurations that would create a vortex as the air enters the sump. Such a configuration can be created, for example, through the use of a diverter vane. Air enters the sump  20  and swirls around the circumference of the sump. The heavier material, namely the water and the debris is forced outward towards the side  60  of the sump  20 , while the lighter air is forced towards the center and upward towards the outlet port  40 . Once the pressure of the system drops, water and debris collected at the bottom  62  of the sump  20  is discharged through the drain port  55 . A pressure actuated valve  50  is used to close the drain port  55  when pressure is applied to the system and to open the drain port  55  to allow exhaust of the water and fine particles of debris when there is little to no pressure in the drain valve  10 . Since the pressure actuated valve  50  is actuated by pressure swings within the sump  20  that result from the normal operation of the compressed air lines, the drain port  55  is automatically accessed to discharge the collected material.  
         [0016]     In the embodiment shown in  FIG. 1 , the drain valve  10  can also include a screen  70  that prevents larger debris from clogging the drain port  55 . As shown in  FIG. 1 , the screen  70  can be positioned between two retaining plates  72  to maintain positioning of the screen. Further, in this embodiment, the drain port  55 , the pressure actuated valve  50 , and screen  70  are formed within a hex cap, or purge nut,  75 , which includes a machined head  76 , a set of threads  77  and an o-ring seal  78 . The threads  77  of the hex cap  75  mate with a set of threads  79  on the drain valve body  80  thereby allowing the hex cap  75  to be easily removed for maintenance. In general, the hex cap or purge nut  75  may be similar to that disclosed in U.S. Pat. No. 5,762,094, which is fully incorporated herein by reference.  
         [0017]     In other embodiments, a screen  71  is positioned between the sump  20  and the outlet  40 , thereby preventing particles from reaching downstream components  25 . It is preferred to use 100 mesh screen. As shown in the drawings, the screens  70  and  71  may be “hat-shaped” such that a portion of each of the screens protrudes into the vortex chamber. Use of screens having such a configuration may assist in stabilizing the vortex of air within the sump. This feature is discussed in U.S. Pat. No. 4,731,228, the entire disclosure of which is hereby incorporated by reference. It should be appreciated that other screen shapes and configurations are contemplated by this invention.  
         [0018]     The some embodiments, the side  60  of the sump  20  and inlet port  30  are extruded aluminum. In other embodiments, they are die-cast plastic or aluminum. In other embodiments other suitable material is used.  
         [0019]     In some embodiments, the hex cap  77  is replaced by a cap with a different number of sides, a bushing, a National Pipe Thread (NPT) fitting, a spin-weld top, an ultrasonic-weld ninety degree top, a screw fastened ninety degree top or other connective fittings, generally referenced as  85 . Such fittings can house the drain port  55  or can be located elsewhere on the drain valve  10 .  FIG. 4  is an illustrative example, wherein a pipe bushing  85  is threadably connected to the top portion  87  of the drain valve  10 , and thus located at the opposite end as the drain port  55 . In other embodiments, the cap can be attached in a non-serviceable manner, such as, for example, crimping or spin-welding. Furthermore, the connective fitting can be metal, such as, for example, brass or steel, or plastic such as, for example, glass-filled polypropylene.  
         [0020]     The drain valve  10  can generally be attached or mounted in any way or fashion, however certain mounting techniques can be used to provide increased benefits. For example, intermodal chassis that are stored vertically can use the drain valve  10  to protect the relay valve from water contamination by arranging the tubing to make a water trap during vertical storage. Water entering the glandhand will be trapped in the drain valve  10  by a loop of tubing. If the water level in the drain valve  10  rises above the centerline, it will begin to drain and the remainder will drain once the chassis is brought to horizontal. Such a configuration is shown in  FIG. 6 .  
         [0021]     It should be appreciated that the drain valve  10  may have different configurations and different designs and that such designs are a part of the invention as they are provided for within the scope of the claims. For example, the present invention contemplates use of non-vortex valve bodies as well as bodies with impingement plates to reduce liquid carryover. Another example would be to replace the pressure actuated valve with a solenoid valve or other automatically controlled valve.