Abstract:
The invention comprises, in one form thereof, a sprayer apparatus that includes a disengageable pressurized fluid source, a pressure chamber in fluid communication with the fluid source, a backflow valve, a sealed vessel, and a sprayer outlet. The backflow valve has two one-way valves separated by a weep mechanism and is positioned between the fluid source and the pressure chamber such that the two one-way valves allow fluid flow from the fluid source to the pressure chamber. The sealed vessel is in fluid communication with the pressure chamber. The sprayer outlet includes a shutoff valve in fluid communication with the pressure chamber. The shutoff valve normally prevents fluid flow from the pressure chamber to the sprayer outlet and is operable to allow fluid flow from the pressure tank to the sprayer outlet.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   This application is a Continuation-in-Part of U.S. patent application Ser. No. 09/934,747, filed Aug. 22, 2001, now U.S. Pat. No. 6,695,228, issued Feb. 24, 2004, which, in turn, claims the benefit of U.S. Provisional Patent Application Ser. No. 60/226,831, filed Aug. 22, 2000. 

   FIELD OF THE INVENTION 
   This invention relates to sprayers used in conjunction with a pressurized hose and a separate tank. 
   BACKGROUND OF THE INVENTION 
   Conventional self-pressurizing garden sprayers require that a pressurized fluid source such as a garden hose be continually connected to the sprayer to provide the spray pressure. Other sprayers may allow the hose to be disconnected after the sprayer is charged however, the hose must be connected to a pressure vessel that is on the ground or otherwise inconvenient to get to. What is needed in the art is a self-pressurizing sprayer with a more convenient method of charging the sprayer. Further, what is needed is a sprayer with an improved backflow valve. 
   U.S. Utility patent application Ser. No. 09/934,747, filed Aug. 22, 2001, now issued under U.S. Pat. No. 6,695,228 on Feb. 24, 2004 is hereby incorporated by reference. 
   SUMMARY OF THE INVENTION 
   The invention comprises, in one form thereof, an apparatus that operates to allow a spray of a liquid from a sealed holding tank to a sprayer handle. The spray fluid is then directed through a shutoff valve and out a sprayer nozzle. The sealed tank is charged by connecting a pressurized fluid source such as a garden hose to the sprayer handle. Examples of spray fluids are insecticides, herbicides, and fertilizers. 
   A novel backflow valve prevents the fluid in the sprayer from escaping through the fluid source fitting when the fluid source is not connected. Further, the backflow valve prevents the spray fluid from contaminating the fluid source. This is especially important if the spray fluid is a pesticide or similar substance and the fluid source is a garden hose connected to a residential water supply. The backflow valve includes two one-way valves and a weep mechanism that restricts backflow pressure. In one embodiment, the weep mechanism includes a port to relieve pressure in the backflow valve if it reaches sufficiently high levels. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The above-mentioned and other features and advantages of this invention, and the manner of attaining them, will become apparent and be better understood by reference to the following description of the embodiments of the invention in conjunction with the accompanying drawings, wherein: 
       FIG. 1  is a side view of a the sprayer apparatus of the present invention; 
       FIG. 2  is a cross-sectional view of the backflow valve of the first embodiment of the present invention; 
       FIG. 3  is a second cross-sectional view of the backflow valve of  FIG. 2 ; 
       FIG. 4  is a cross-sectional view of the backflow valve of the second embodiment of the present invention; and 
       FIG. 5  is a second cross-sectional view of the backflow valve of  FIG. 4 . 
   

   Corresponding reference characters indicate corresponding parts throughout the several views. The examples set out illustrate certain embodiments of the invention but do not delineate the scope of the invention. 
   DETAILED DESCRIPTION 
     FIG. 1  displays the sprayer apparatus of the present invention. The sprayer  10  includes a housing  12 , a backflow valve  14  ( FIG. 2 ), a discharge tube  16 , and a sealed vessel  18 . 
   The housing  12  includes a pressurization chamber  20 , a discharge chamber  22 , a shutoff valve  24 , and a quick-disconnect receptacle  26 . The shutoff valve  24  normally seals the pressurization chamber  20  off from the discharge chamber  22 . The shutoff valve  24  includes a valve release  28 . The valve is opened by depressing the valve release  28  to thereby place the pressurization chamber  20  in fluid communication with the discharge chamber  22 . The quick-disconnect receptacle  26  is affixed to or integral with the pressurization chamber  20  and is configured to cooperate with a pressurized fluid source  30  having a quick disconnect attachment. The fluid source is preferably a hose such as a garden hose connected to a domestic water supply. The hose may alternatively be connected to a tank that is pressurized by a pump. 
   The backflow valve  14  is situated between the fluid source  30  and the pressurization chamber  20  allowing fluid to flow to the pressurization chamber  20  from the fluid source  30  and preventing fluid flow in the reverse direction. The backflow valve  14  is best shown in  FIG. 2 . The backflow valve  14  includes a source-side chamber  32 , a source-side stopper  34 , a weep chamber  36 , an outlet stopper  38 , and an outlet chamber  40 . The source-side stopper  34  is configured to prevent fluid flow from the weep chamber  36  to the source-side chamber  32  and allow fluid flow in the reverse direction. Similarly, the outlet stopper  38  is configured to prevent fluid flow from the outlet chamber  40  to the weep chamber  36  and allow fluid flow in the reverse direction. The weep chamber  36  encloses a button head screw  42 , a weep plunger  44 , and a spring  46 . The weep plunger  44  is normally biased against the head of the button head screw  42  by the spring  46 , however higher pressure on the source side of the weep chamber  36  forces the weep plunger  44  to travel along the button head screw  42  until a shoulder  48  prevents the weep plunger  44  from traveling further toward the outlet side of the weep chamber  36 . The button head screw  42  therefore acts as a plunger guide. The weep plunger  44  has a plurality of through holes  50  that are configured such that the head of the button head screw  42  covers the majority of each through hole when the weep plunger  44  engages the head of the button head screw  42 . The button head screw  42  is retained within the weep chamber  36  by a partition  52 , which is perforated to allow fluid flow within the weep chamber  36 . 
   The discharge tube  16  is in fluid communication with the discharge chamber  22 . An elongated discharge tube  16  is shown in  FIG. 1 , however tubes and nozzles of many different shapes and configurations can be imagined. 
   The sealed vessel  18  is connected to the pressurization chamber  20  by a flexible tube  54 . The sealed vessel  18  contains a fluid that is to be sprayed by the sprayer  10 . Examples of fluids that may be used are fertilizers, insecticides, herbicides, etc. The sealed vessel  18  is sealed such that the only fluid communication into and out of the sealed vessel  18  is through the flexible tube  54 . 
   In use, an amount of the spray fluid that is to be sprayed by the sprayer  10  is placed into the sealed vessel  18 , which is then connected to the pressurization chamber  20  by the flexible tube  54  and is otherwise sealed shut. The pressurized fluid source  30  is connected to the quick-disconnect receptacle  26 . The pressurized fluid flows through the backflow valve  14  into the pressurization chamber  20  and through the flexible tube  54  to the sealed vessel  18 . The backflow valve is shown during charging of the sprayer  10  in  FIG. 3 . The fluid flows past source-side stopper  34  and applies pressure to the weep plunger  44 , which travels along the button head screw  42  against the spring  46  to seat against the shoulder  48 . Thus the through holes  50  are fully open to allow increased fluid flow within the weep chamber  36 . The fluid then flows past outlet stopper  38  and into pressurization chamber  20 . Since there is no outlet for the fluids within the sprayer  10 , there is a buildup of pressure within the pressurization chamber  20  and the sealed vessel  18 . As the pressure in the sprayer  10  equalizes with the pressurized fluid source, the fluid flow within the backflow valve  14  decreases and the spring  46  forces the weep plunger  44  against the head of the button head screw  42  as shown in  FIG. 2 . Further, the outlet stopper  38  and the source-side stopper  34  close. The fluid source  30  may be removed from the quick-disconnect receptacle  26  once the sealed vessel  18  is pressurized. The valve release  28  is then depressed to open the shutoff valve  24  and discharge the fluid in the pressurization chamber  20  and the sealed vessel  18  through the discharge chamber  22  and the discharge tube  16 . When the sprayer  10  needs to be recharged, the user releases the valve release  28  to close the shutoff valve  24 . The sprayer  10  is then pressurized again and the process is repeated until the spray fluid in the sealed vessel  18  is gone. 
   The sprayer  10  can alternatively be configured so that the fluid source  30  remains engaged with the quick-disconnect receptacle  26  during the spraying process. In this alternative, the fluid source  30  pressurizes the pressurization chamber  20  and the sealed vessel  18  as the user opens and closes the shutoff valve  24 . Thus the sprayer  10  remains pressurized and the sprayer can be used until the spray fluid is gone. 
   In the case that there is a sudden drop in pressure in the fluid source  30 , the backflow of fluid in the pressurized chamber  20  and thus outlet chamber  40  could possibly be so rapid that some of the spray fluid that entered the pressurized chamber  20  from the sealed vessel  18  enters the weep chamber  36  before the backpressure forces the outlet stopper  38  to close. The pressure drop in weep chamber  36  allows the spring  46  to force the weep plunger  44  against the button head screw  42  thus limiting fluid flow within the weep chamber  36 . The source-side stopper  34  closes before any spray fluid may pass into the source-side chamber  32 . Thus, the backflow valve  14  is configured such that even if some spray fluid enters the weep chamber  36 , the spray fluid is prevented from contaminating the fluid source  30 . 
   In a second embodiment, the backflow valve  14  is replaced by backflow valve  114  shown in  FIG. 4 . The same reference numbers are used to indicate features in the backflow valve  114  that are similar or substantially identical to those in the backflow valve  14 . 
   Similarly to the backflow valve  14 , the backflow valve  114  is situated between the fluid source  30  and the pressurization chamber  20  allowing fluid to flow to the pressurization chamber  20  from the fluid source  30  and preventing fluid flow in the reverse direction. The backflow valve  114  includes a source-side chamber  32 , a source-side stopper  34 , a weep chamber  136 , an outlet stopper  38 , and an outlet chamber  40 . The weep chamber  136  encloses a weep diaphragm  144 , a shoulder  148 , and a weep slot  150 . The weep diaphragm  144  includes a through hole to allow fluid to flow within weep chamber  136 . The weep slot  150  is on the outlet side of the weep diaphragm  144  and is in fluid communication with a channel  152  in the housing  12 . A push-in stopper  154  normally seals the channel  152  to prevent fluid in the weep slot  150  from leaking. A significant pressure within the weep chamber  136  and thus the weep slot  150  may eject the push-in stopper  154  from the channel  152 . The push-in stopper  154  may be attached to the housing  12  or the backflow valve  114  to prevent it from being lost if it is ejected from the channel  152 . 
   In use, the fluid flow through the backflow valve  114  from the fluid source  30  is shown in  FIG. 5 . The fluid from the fluid source  30  flows past the source-side stopper  34  into the weep chamber  136 . The fluid pressure on the source side of the weep diaphragm  144  forces the weep diaphragm off shoulder  148  thus closing off the weep slot  150  to prevent the push-in stopper from being ejected while the sprayer  10  is being charged. The fluid flows through the through hole in the weep diaphragm  144  and past the outlet stopper  38  into the pressurization chamber  20 . When the pressure in the pressurization chamber  20  has equalized with the pressure in the fluid source  30 , the outlet stopper  38  and the source-side stopper  34  close the respective outlet chamber  40  and the source-side chamber  32 . Thus fluid flow from the outlet side to the source side of the backflow valve  114  is prevented and the fluid source  30  may be disconnected. 
   In the case that there is a sudden drop in pressure in the fluid source  30 , the backflow of fluid in the pressurized chamber  20  and thus outlet chamber  40  could possibly be so rapid that some of the spray fluid that entered the pressurized chamber  20  from the sealed vessel  18  enters the weep chamber  136  before the backpressure forces the outlet stopper  38  to close. The pressure drop in weep chamber  136  forces the weep diaphragm  144  against the shoulder  148  thereby opening the weep slot  150 . Further, the shoulder  148  restricts the amount the weep diaphragm  144  may flex toward the source side of the weep chamber  136  thus restricting the fluid flow towards the source-side stopper  34  and providing time for the source-side stopper  34  to close. The pressure within the weep chamber  136  is communicated to the now open weep slot  150  and if a sufficient pressure is reached, the push-in stopper  154  is ejected. Therefore the pressure within the weep chamber  136  is relieved before a pressure that could cause a failure in the source-side stopper  34  is reached. Thus, the backflow valve  114  is configured such that even if some spray fluid enters the weep chamber  136 , the spray fluid is prevented from contaminating the fluid source  30 . 
   It should be noted that the quick-disconnect receptacle  26  may be replaced by another type of receptacle such as an externally threaded receptacle configured for cooperating with a standard garden hose. Further, each of the backflow valves  14  and  114  are shown with a 3 piece chamber wall construction, however embodiments having fewer pieces or more pieces may be imagined. Even further, the first embodiment of the backflow valve may include a weep slot and push-in stopper similar to that used in the second embodiment in order to provide an outlet for the fluid in the weep chamber if the pressure reaches significant levels. 
   While the invention has been described with reference to preferred embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the scope of the invention. 
   Therefore, it is intended that the invention not be limited to the particular embodiments disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope and spirit of the appended claims.