Fluid Dose Dispensing Apparatus

Abstract

An apparatus for dosing a fluid flow system with a treatment fluid/chemicals is described. The apparatus includes: a vessel; an inlet pipe and an outlet pipe for coupling to the system so that fluid from the system may flow into the vessel and return into the system to flush chemicals from within the vessel into the system. The vessel has a piston within it and the vessel wall defines a cylinder in which the piston moves under pressure of incoming fluid from a first position at which the vessel contains fluid to be dispensed into the system to a second position corresponding to substantially complete emptying of the vessel. The piston has a bypass passage through or around it that opens when the piston substantially reaches the second position so that fluid from the system may flow passed the piston when the piston is at the second position.

I claim: 
     
         1 . Apparatus for dispensing a dose of fluid, the apparatus comprising a dispensing vessel with a dispensing outlet, the vessel having a piston and a vessel wall defining a cylinder in which the piston may move under pressure from a first position to a second position, wherein the apparatus has a bypass passage that extends through the first piston and has a valve member that is opened by a valve actuating plunger in the piston that moves within the piston to push the valve open when the valve actuating plunger abuts a shoulder at or near the second position in the vessel. 
     
     
         2 . Apparatus as claimed in  claim 1 , wherein the apparatus is adapted to dispense two or more doses of fluid in sequence and the vessel has at least a first chamber and a second chamber separated by the piston. 
     
     
         3 . Apparatus as claimed in  claim 2 , wherein the first chamber is proximate a dispensing outlet end of the vessel and the second chamber is remote from the dispensing outlet and the first position of the piston corresponds to a position at which the first chamber of the vessel contains a first dose of fluid to be dispensed and the second position corresponds to substantially complete emptying of the first chamber of the vessel, whereupon the opening of the valve in the piston enables a second dose of fluid to be dispensed. 
     
     
         4 . Apparatus as claimed in  claim 1 , wherein the apparatus has at least a first chamber and a second chamber separated by the piston and further comprises a second piston in the vessel and which defines a boundary to a third chamber in the vessel. 
     
     
         5 . Apparatus as claimed in claim wherein the apparatus is a handheld device having a manually driven plunger at one end of the vessel whereby pressure is applied by the manual plunger to drive fluid through the vessel from said one end to a dispensing outlet at the other end of the vessel. 
     
     
         6 . Apparatus as claimed in  claim 5 , wherein the apparatus is a manual ratchet-driven plunger-operated cartridge device (e.g., a caulking gun). 
     
     
         7 . Apparatus as claimed in  claim 5 , wherein the apparatus is a syringe. 
     
     
         8 . Apparatus as claimed in  claim 1 , wherein the apparatus is adapted to dispense fluid in a sequence of stages comprising a mixing stage and a dispensing stage. 
     
     
         9 . Apparatus as claimed in  claim 1 , wherein the vessel has a first chamber proximate a dispensing outlet end of the vessel and a second chamber remote from the dispensing outlet end and a first piston between the first chamber and second chamber whereby when the piston moves under pressure from the first position to the second position the bypass passage in the piston opens to allow the fluid in the second chamber to be transferred into the first chamber to mix with the contents of the first chamber. 
     
     
         10 . Apparatus as claimed in  claim 9 , wherein the fluid held in the second chamber is a liquid and the first chamber holds a solid that dissolves in or otherwise mixes with the liquid or is also a liquid. 
     
     
         11 . Apparatus as claimed in  claim 1 , wherein the shoulder at the second position is an annular shoulder. 
     
     
         12 . Apparatus as claimed in  claim 11 , wherein the annular shoulder is formed by a piston. 
     
     
         13 . Apparatus as claimed in  claim 11 , wherein the annular shoulder is formed by a ring that is connected to the wall of the vessel. 
     
     
         14 . Apparatus as claimed in  claim 13 , wherein the ring is connected to the wall of the vessel by frangible connections that break when the piston is pressured sufficiently. 
     
     
         15 . Apparatus as claimed in  claim 14 , wherein the frangible connections are configured to break when a manual plunger presses directly against the piston and the piston against the ring. 
     
     
         16 . Apparatus as claimed in  claim 7 , wherein the syringe has a hollow cylindrical plunger with a piston part at one end of the plunger to drive the fluid towards the dispensing outlet of the syringe, wherein the said piston having the bypass passage, valve member and valve actuating plunger is the piston part of the hollow cylindrical plunger, the hollow cylindrical plunger defining therewithin a chamber in which a fluid may be held to be dispensed through the bypass passage. 
     
     
         17 . Apparatus for dosing a fluid/water flow system with one or more treatment chemicals, the apparatus comprising: a vessel: an inlet pipe or hose and an outlet pipe or hose for coupling to the system so that fluid/water from the system may flow into the vessel and fluid from the vessel may flow from within the vessel out of the vessel and into the system, the vessel having a piston therewithin and the vessel wall defining a cylinder in which the piston moves under pressure of incoming fluid from a first position at which the vessel contains fluid to be dispensed to a second position corresponding to substantially complete emptying of the vessel, wherein the apparatus has a bypass passage through or around the piston that opens when the piston substantially reaches the second position so that fluid/water from the system may flow passed the piston when the piston is at the second position to flush the vessel. 
     
     
         18 . Apparatus as claimed in  claim 17 , wherein the bypass passage extends through the piston and has a valve member that is opened by a valve actuating plunger in the piston that moves within the piston to push the valve open when the valve actuating plunger abuts a shoulder at or near the second position in the vessel. 
     
     
         19 . Apparatus s claimed in  claim 17 , wherein the vessel is a transparent vessel or has a transparent portion of wall to allow the user to view the piston moving into the second position. 
     
     
         20 . Apparatus as claimed in  claim 17 , wherein a pressure gauge is provided mounted on the exterior of the vessel and coupled to the interior of the vessel by a conduit to monitor the pressure in the vessel. 
     
     
         21 . Apparatus as claimed in  claim 20 , wherein the pressure gauge is coupled to the interior of the vessel on the side of the piston where fluid flows into the vessel. 
     
     
         22 . Apparatus as claimed in  claims 17 , wherein the vessel is formed with a hollow central cylindrical body that is initially open at each end and has a first end plate and a second end plate mounted thereto each to sealingly close off a respective open end, at least one of which is readily demountable following use to allow for ease of maintenance. 
     
     
         23 . Apparatus as claimed in  claim 22 , wherein the demountable plate is bolted in place to the cylindrical body. 
     
     
         24 . Apparatus as claimed in  claim 23 , wherein the first end plate is bolted to the second end plate sandwiching and clamping the cylindrical body therebetween. 
     
     
         25 . Apparatus as claimed in  claim 17 , wherein the bypass passage comprises one or more internal longitudinal grooves/channels in the wall of the vessel's tubular cylindrical body at the outlet end so that as the piston moves against the upper plate the grooves/channels allow the mains water to pass across the piston circumferential surface 
     
     
         26 . Apparatus for dosing a central heating system with one or more treatment chemicals, the apparatus comprising: a vessel; an inlet pipe or hose and an outlet pipe or hose for coupling to the system so that fluid/water from the system may flow into the vessel and fluid from the vessel may flow from within the vessel out of the vessel and into the system, the vessel having a piston therewithin and the vessel wall defining a cylinder in which the piston moves under pressure of incoming fluid from a first position at which the vessel contains fluid to be dispensed to a second position corresponding to substantially complete emptying of the vessel.