Abstract:
An apparatus for operator controlled purging of the tanks of a pressurized air reservoir of a vehicle air system comprises an air actuated normally closed drain valve mounted to an underside of each tank, a source of pressurized air engaged to each drain valve, and a controller for each valve engaged downstream of the source, and within a driver area of the vehicle, the controller when activated, allowing for communication between the source and the drain valve for opening of the valve. The method for using the apparatus in testing air system integrity includes the steps of draining and refilling each tank individually in a pre-defined sequence while monitoring driver area mounted indicators of air pressure levels and testing functionality of an air system operated service brake system of the vehicle by carrying out the pre-defined sequence.

Description:
This is a division of application Ser. No. 08/920,153, filed Aug. 26, 1997 now U.S. Pat. No. 5,936,154. 
    
    
     BACKGROUND OF THE INVENTION 
     The present invention relates to a driver-controlled contaminant purging apparatus for use in draining air tanks or compartments of a pressurized pneumatic reservoir of a vehicle such as a truck or a bus and a method of using same in testing the integrity of an air brake system of the vehicle. More specifically, the apparatus allows the vehicle operator to single-handedly test functionality of the air service brake system from within a driver area of the vehicle such test typically being referred to as a pre-trip air system inspection. 
     THE PRIOR ART 
     Heretofore, various drain valve apparatus for use in purging contaminants from a pneumatic tank of a vehicle air brake system and methods of use have been proposed. 
     Most recently, a drain valve and method for using same in automatically draining condensation and contaminants from a wet tank in a pneumatic braking system of a vehicle have been proposed in the Chille, Sr. U.S. Pat. No. 5,435,422. Automatic operation of the drain valve is controlled by vehicle ignition, with engine ignition acting to close the drain valve and engine shut off acting to open the drain valve. To date, however, a contaminant purging apparatus for use in a vehicle air system by means of which a pre-trip inspection of the vehicle air and service brake system may be performed by an operator while in a driver area of the vehicle has not been proposed. 
     SUMMARY OF THE INVENTION 
     Accordingly, a primary object of the apparatus and method of the present invention is not only to purge contaminants from all compartments of an air reservoir of a vehicle air system but also to provide an operator with an apparatus by means of which a method for single-handedly performing a mandatory pre-trip air and service brake system inspection from a driver area of the vehicle may be carried out. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Other objects and advantages of the invention will become more apparent upon perusal of the detailed description thereof and upon inspection of the drawings in which: 
     FIG. 1 is a schematic block diagram illustrating the contaminant purging apparatus of the present invention incorporated into a pneumatic or air system of a vehicle which primarily functions in vehicle service brake operation. 
     FIG. 2 is a perspective view of a portion of a vehicle dashboard showing placement of actuation switches and a dual air pressure gauge of the apparatus thereon. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring now to the drawings in greater detail there is illustrated schematically in FIG. 1 an air system  10  of a vehicle  101  which incorporates a contaminant purging apparatus  12  made in accordance with the teachings of the present invention. The air system  10  obtains its required supply of air from a compressor  14  and uses the air primarily for operation of a vehicle service brake system  15 . The compressor  14  feeds air into a compartmentalized multi-tank air reservoir  16  engaging a first compartment or tank of reservoir  16  which is typically referred to as the wet tank  18 . Air from the wet tank  18  then flows to each of two further compartments or tanks of the reservoir  16 , a first such compartment being considered a primary rear end tank  20  and the second compartment being identified as the secondary front end tank  22 . 
     Air is supplied to the primary rear end tank  20  and the secondary front end tank  22  from the wet tank  18  through a one way check valve  24  interposed in each of two dividing walls  25  separating the wet tank  18  from the secondary front end tank  22  and the primary rear end tank  20 . Each one way check valve  24  insures that air entering the primary rear end tank  20  and the secondary front end tank  22  cannot return to the wet tank  18 . 
     In a typical installation, the primary rear end tank  20  supplies air to at least a rear brake portion  26  of the service brake system  15  of the vehicle  101  while the secondary front end tank  22  supplies air to at least a front brake portion  28  of the service brake system  15  of the vehicle  101 . 
     The air system  10  is also capable of accommodating an secondary ancillary tank  27 , engaged functionally to the secondary front end tank  22  of the reservoir  16 . Such an ancillary tank  27  may at times be desirable for providing a substantially increased supply of pressurized air for use in braking of a vehicle, such as on a school bus. 
     The wet tank  18 , the primary rear end tank  20 , and the secondary front end tank  22  are each operatively engaged to a low pressure warning device  29  which functions to advise an operator of a low pressure condition within the air system  10  which would seriously affect full braking capability. The primary rear end tank  20  and the secondary front end tank  22  are each also functionally engaged to a pressure gauge  30  mounted on a dashboard  31  within a driver area  32  of the vehicle  101 , with pressure in each of the primary rear end tank  20  and the secondary front end tank  22  being separately indicated on the pressure gauge  30 . See FIGS. 1 and 2. 
     The secondary front end tank  22 , by means of a suitable coupling  33 , not only engages the front brake portion  28  of the vehicle  101  but also typically supplies air, via a protection valve  34  to ancillary air operated devices  36  of the vehicle  101 , such as, for example, an air horn, a door actuating cylinder of a bus, etc. The protection valve  34  is a normally open valve. Should air pressure drop in the secondary front end tank  22 , the protection valve  34  will automatically close, in response to the decreased pressure, blocking any further draw of air there through to any downstream devices. The automatic closure of the protection valve  34  is an attempt by the air system  10  to maintain sufficient air pressure there within for operability of the front brake portion  28  of the vehicle  101 . 
     For accommodation of the contaminant purging apparatus  12  of the present invention, the typical direct supply to the ancillary air operated devices  36  from the protection valve  34  has been eliminated. Rather, a manifold or a splitter  38  is instead engaged downstream of the protection valve  34 . The splitter  38  includes a plurality (four shown in FIG. 1) of outlets: first outlet  42 , second outlet  44 , third outlet  46 , and fourth outlet  40 . 
     The fourth outlet  40  is provided for supplying air to the ancillary air operated devices  36 . Each of the three further outlets  42 ,  44 ,  46  ultimately engage one of a plurality of three normally closed air-operated drain valves  48   a ,  48   b , and  48   c  respectively, each of which in turn engages and serves one of the tanks of reservoir  16 . First outlet  42  engages first drain valve  48   a  of wet tank  18 , Second outlet  44  engages second drain valve  48   b  of primary rear end tank  20 , and third outlet  46  engages third drain valve  46   c  of secondary front end tank  22 , in the embodiment illustrated in FIG.  1 . 
     Interposed between each of the first outlet  42 , the second outlet  44 , and the third outlet  46  and their respective drain valves  48   a ,  48   b ,  48   c , are controller  50   a , controller  50   b , and controller  50   c , respectively, which may be defined as the first, second, and third vented momentary control valves  50   a ,  50   b , and  50   c . The first momentary control valve  50   a  is a normally closed valve and incorporates a spring biased toggle switch  52   a  which must be manually activated and held activated by an operator to cause the first momentary control valve  50   a  to open and be maintained in an open condition. Toggle switch  52   a  is located within a driver area  32  of vehicle  101 . See FIG.  2 . Once toggle switch  52   a  is released, the first momentary control valve  50   a  closes under action of a spring (not shown) and air downstream of the first momentary control valve  50   a  is vented therethrough via a vent port  51   a  thereof. The second and the third momentary control valves  50   b  and  50   c  operate similarly as the first momentary control valve  50   a  with toggle switches  52   b  and  52   c , springs and vent ports  51   b  and  51   c , respectively. Additionally, toggle switches  52   b  and  52   c  are also located within driver area  32 . 
     Each of the drain valves  48   a ,  48   b , and  48   c  is positioned to engage a downwardly directed area of the wet tank  18 , the primary rear end tank  20 , and the secondary front end tank  22 , respectively, gravity assisting in draining sludge containing contaminants and moisture as well as air from each of the wet tank  18 , the primary rear end tank  20  and the secondary front end tank  22 . 
     In use, when the toggle switch  52   a  of first momentary control valve  50   a , for example, is held in an activated position, air from the first outlet  42  is supplied therethrough to the first drain valve  48   a , opening the first drain valve  48   a  so that the contents of the wet tank  18  passes therethrough, into the ambient environment, effectively purging the wet tank  18 . 
     It has been stated above that the contaminant purging apparatus  12  not only provides for the purging of moisture and contaminants from the air system  10  with such purging being accomplished from the driver area  32  of the vehicle  101  single-handedly by the operator, but also provides a workable method for testing of the service brake system  15  of the vehicle  101  by the operator. 
     In this respect, it has been found that a specific sequence of steps taken during draining of the wet tank  18 , the primary rear end tank  20 , and the secondary front end tank  22  will not only purge the wet tank  18 , the primary rear end tank  20 , and the secondary front end tank  22  but will also test the integrity of the air system  10  of the vehicle  101 . 
     The steps to be followed in undertaking the method begin with starting the vehicle engine  54  (shown in phantom) of the vehicle  101 . The reservoir  16 , as well as any ancillary tank(s)  27  engaged to and including the wet tank  18 , the primary rear end tank  20 , and the secondary front end tank  22  thereof, are fully charged by pressurized air pumped thereinto by the compressor  14  which is engine activated by the starting the vehicle engine  54 . The compresser  14  is controlled by a governor  56  (not shown) which deactivates the compressor  14  upon sensed full air charging of the wet tank  18 , the primary rear end tank  20 , and the secondary front end tank  22 . The vehicle engine  54  is then stopped and an ignition switch  58  thereof is then turned to the ‘accessory’ position. See FIGS. 1 and 2. 
     The driver engages the first momentary control valve  50   a  by repositioning and holding the toggle switch  52   a  in such position which opens the first drain valve  48   a  for draining the wet tank  18 , purging air, moisture and contaminants from the wet tank  18 . 
     During purging of the wet tank  18 , the operator observes the pressure gauge  30  which provides readings of pressure within the primary rear end tank  20 , and the secondary front end tank  22 , respectively. If the pressure readings for the primary rear end tank  20 , and the secondary front end tank  22  remain constant during purging, such constancy indicates that the check valves  24  between the wet tank  18  and the primary rear end tank  20 , and between the wet tank  18  and the secondary front end tank  22 , respectively are functioning in the closed position. If a drop in air pressure in either the primary rear end tank  20 , and the secondary front end tank  22  is noticed, the pressure drop indicates a malfunction of the corresponding check valve  24 . As the depletion of air within the wet tank  18  continues, the pressure within the wet tank  18  drops to a preset bottom limit which should actuate the low pressure indicator  29 . See FIG.  2 . If the low pressure indicator  29  does not activate and there is an audible indication of air bleeding from the wet tank  18 , a malfunction of the low pressure indicator  29  is indicated. 
     Once testing of the low pressure indicator  29  is completed, the toggle switch  52   a  for the first momentary control valve  50   a  is released, closing the first drain valve  48   a  on the wet tank  18  and allowing air used to open the first drain valve  48   a  to exit to the outside environment via vent port  51   a.    
     The vehicle engine  54  is then restarted and the wet tank  18  is fully recharged by the compressor  14 , with the operator having an indication of such recharging taking place when the low pressure indicator  29  ceases activity. Further, the operator will also be apprised of full repressurization within the wet tank  18  when the audible sound of the governor  56  of the compressor  14  ceases. The process of fully recharging the wet tank  18  within an acceptable period of time provides an indication that the compressor  14 , the governor  56  thereof, any supply lines between the compressor  14  and the wet tank  18 , as well as any check valves engaged in such lines, are functioning. If recharging takes too long, intervening component integrity must be checked. 
     Once full pressure is restored in the wet tank  18 , the operator again turns the vehicle engine off and sets the vehicle ignition  58  to ‘accessory’, negating the compressor  14  capability. 
     The operator then repositions and holds the toggle switch  52   c  in this position for the third momentary control valve  50   c  to open, activating the third drain valve  48   c  of the secondary front end tank  22 , to purge the secondary front end tank  22 . As purging of the secondary front end tank  22  continues, the pressure gauge  30  should indicate that pressure in the secondary front end tank  22  is dropping. When pressure within the secondary front end tank  22  reaches the low air pressure limit, the low pressure indicator  29  should again activate, indicating functionality. Closure of protection valve  34  on a low pressure condition will not disrupt the test as the third drain valve  48   c  will remain open due to air locked in between the third momentary control valve  50   c  and the third drain valve  48   c ; the third momentary control valve  50   c  acting as a check valve in this respect. 
     Once the air pressure drops to this level, the front brake portion  28  of the service brake system  15  is disabled. The operator then restarts vehicle engine  54 , immediately engages the vehicle transmission (not shown) and rolls the vehicle  101  forwardly. A vehicle brake pedal  60  is then engaged to test integrity of the rear brake portion  26  of the service brake system  15 , in the absence of a functional front brake portion  28 . Immediate engagement of the vehicle transmission and the brake pedal  60  is required to test the rear brake portion  26  prior to the compressor  14  recharging the secondary front end tank  22 ; the compressor  14  having started with the vehicle engine  54 . 
     The third momentary control valve  50   c  toggle switch  52   c  is released closing the drain valve  48   c , and the secondary front end tank  22  is fully recharged, the indication of which is acquired by viewing the pressure gauge  30 , as well as being indicated by the compressor  14  stoppage, and the time period for full recharge is again monitored. 
     The operator again turns the vehicle engine  54  off and sets vehicle ignition  58  to ‘accessory’, negating the compressor  14  capability. 
     The above described steps for draining the secondary front end tank  22  and checking integrity of the portion of the air system  10  not operatively engaged thereto are repeated for the primary rear end tank  20 . Here, integrity of the portion of the air system  10  not operatively engaged to the secondary front end tank  20  includes the front brake portion  28  of the vehicle  101  which is then tested in the absence of a functional rear brake portion  26  of the service brake system  15 . 
     The method steps of the procedure set forth above, when carried out in the manner described, provide a full inspection of the air system  10  of the vehicle  101 , comfortably and conveniently by an individual operator seated within the driver area  32  of the vehicle  101 , such positioning within the driver area  32  allowing for observational access to audible and visible observations of the low pressure indicator  29  and the pressure gauge  30  respectively, during a full cycle of testing operation of the air system  10 . 
     Such full cycle operational testing cannot be accomplished presently without the operator necessarily being outside of the vehicle to manually operate drain petcocks on the tanks, nor can such testing be accomplished with any automatic system presently available for purging. 
     As described above the contaminant purging apparatus  12  and method of using same of the present invention provide a number of advantages, some of which have been described above, and others of which are inherent in the invention. Also, modifications may be proposed to the contaminant purging apparatus  12  and method without departing from the teachings herein. Accordingly, the scope of the invention is only to be limited as necessitated by the accompanying claims.