STEAM CLEANING APPARATUS

Abstract: A steam cleaning apparatus comprising a combustion chamber (50) having an inlet means (48) arranged to be connected to a source of compressed air and a source of compressed combustible gas, and exhaust gas outlet means (58), a further inlet means (14) arranged to be connected to a supply of water, said further inlet means (14) being arranged to supply water to a heat receiving location in or adjacent to the combustion chamber (50) so that the water can be heated by combustion of the air and combustible gas, said apparatus further comprising a respective supply line (12, 10, 14) for gas, air and water and each supply line (12, 10, 14) containing a fluid pressure regulator (20, 18, 22) having an active side and a passive side, characterised in that inter-regulator conduit means (72, 74, 80) is provided for applying the regulated fluid pressure from the passive side or sides of one or more regulators (20, 18, 22) to the active sides of at least two regulators (20, 18, 22).

Description: TITLE STEAM CLEANING APPARATUS DESCRIPTION The present invention relates to steam cleaning appar¬ atus of the type in which combustion of fuel within a chamber is employed to heat water sufficiently to pro¬ duce a continuous stream of steam. FIELD OF THE INVENTION Steam cleaning apparatus of the type with which the present invention is concerned is described in British Patent Nos. 773048 and 1449483, Australian Patent No. 204121 and South Africa Patent No. 4435/63. British Patent No. 773048 describes apparatus which con¬ sists of a combustion chamber into which a mixture of fuel and air is burnt after ignition by a spark plug, this combustion chamber being surrounded by a jacket into which is fed a mixture of water and detergent, or some other cleaning liquid. The combustion chamber and the cleaning fluid jacket share a common outlet pipe from which there flows a mixture of the hot combustion prod¬ ucts and vaporized cleaning liquid. British Patent No. 1449483 describes an apparatus for steam cleaning comprising a combustion chamber having an inlet passage for a combustible fluid and an exit passage for exhaust gases, said combustion chamber co¬ operating in heat exchange relationship with a second chamber having an inlet port for the admission of water and an outlet port for steam, said outlet port and exit passage communicating at a mixing region with a fluid conduit, and means for admitting a cleaning fluid to said fluid conduit downstream of said mixing region. SUMMARY OF THE INVENTION In steam cleaning apparatus where the fuel is a gas it is highly desirable that the amount of gas introduced into the mixture be controlled within fairly close tolerance. In fact, it is preferred that the pressure of the gas introduced be slightly higher than the pressure of air so as to obtain reliable combustion. Problems can arise if the air pressure fluctuates. For example if compressed air is supplied from a compressor the air pressure supplied to the steam cleaning apparatus can drop if the compressor is used to supply compressed air for other purposes. Additionally, problems can also occur if the gas pressure fluctuates. For example, on cold days the pressure of the gas in a bottle can be lowered rapidly because, as gas is drawn off, the rate of gas generation from liquid in the bottle is reduced. OMH Similarly, it is desirable to co-ordinate the amount of air and gas i.e. the volume of the combustible mixture, with the water pressure since, for example, if the water pressure falls then the amount of combustible mixture required to convert the water into steam will also fall. If the water pressure is excessive flooding of ignition means in the apparatus can occur due to excessive back pressure causing water to enter a com¬ bustion chamber. In accordance with one aspect of the present invention there is provided a steam cleaning apparatus comprising a combustion chamber having an inlet means arranged to be connected to a source of compressed air and a source of compressed combustible gas, and exhaust gas outlet means, a further inlet means arranged to be connected to a supply of water, said further inlet means being arranged to supply water to a heat receiving location in or adjacent to the combustion chamber so that the water can be heated by combustion of the air and combustible gas, said apparatus further comprises a respective supply line for gas, air and water and each supply line containing a fluid pressure regulator having an active side and a passive side, characterised in that inter-regulator conduit means is provided for applying the regulated fluid pressure from the passive side or sides of one or more regulators to the active sides of at least two regulators. Preferably, means is provided for introducing a cleaning substance into the aqueous fluid. Preferably, the regulation means is arranged such that the water pressure is below the air pressure whilst the gas pressure is above the air pressure. BRIEF DESCRIPTION OF THE DRAWINGS The present invention will now be described, by way of example, with reference to the accompanying drawings, in which; FIGURE 1 is a schematic drawing of a steam cleaning ap¬ paratus in accordance with the present invention; FIGURE 2 is a sectional view of a fluid pressure regulator used in the apparatus of Figure 1; and FIGURES 3 to 11 show schematically various alternative regulator systems to the one shown in Figure 1. DESCRIPTION OF THE INVENTION In Figure 1 of the drawings, there is shown a steam cleaning apparatus comprising an air supply inlet line 10, a gas supply inlet line 12 and a water supply inlet line 14. The line 10 contains a non-return valve 16 and a fluid pressure regulator 18. The line 12 contains a fluid pressure regulator 20 and the line 14 contains a fluid pressure regulator 22. A suitable regulator for use in the present invention is the SMC air regulator model AR200. The regulators 18 O PI_ and 20 are of the general type shown in Figure 2 which comprises a housing 24, and adjustment spindle 26, a locknut 28, a diaphragm 30, a spring 32 between the spindle 26 and the diaphragm 30. The spindle 26 is threaded and is threadedly engaged with the housing 24. There is an inlet port 34 and an outlet port 36. A pin 31 extends downwardly from the diaphragm 30 to a disc 33 urged upwardly by a small counter spring 35. The disc 33 is arranged to be urged into engagement with a valve seat by the spring 35 when there is no exerted pressure on the diaphragm 30. In this position no gas can pass through the regulator. Fluid passing between the ports 34 and 36 must pass between the valve seat and the disc 33 which path governs the outlet pressure to a desired level. The level of the outlet pressure is controlled by the position of the diaphragm 30 which controls the position of the disc 33 by means of the pin 31. Thus, if the diaphragm is lowered (as seen in Figure 2) by exerted pressure, such as from the spring 32, the governed gas pressure of the outlet port is increased. The regulator shown in Figure 2, is modified by having a port 38 on the side of the diaphragm 30 remote from the ports 34 and 36. As will be described the port 38 is connected by a conduit, in use, to another regulator so that the regulated fluid pressure of that other regulator is applied to the diaphragm 30 in addition to the pressure of the spring 32. Henceforth, the side of a regulator which has means arranged to act on a dia¬ phragm to open same will be called the active side while the opposite side of a regulator will be called the passive side. The regulator 22 is similar to the regulators 18 and 20 except that the spindle 26, locknut 28 and spring 32 are dispensed with. Thus, the pressure exerted on the diaphragm 30 is solely fluid pressure. Turning again to Figure 1, the lines 10 and 12 feed through their respective regulators into a block 40 containing a mixing chamber 42. As shown, the mixing chamber 42 contains an air non-return valve 44 and a gas non-return valve 46. The air and gas are admixed in use, in the chamber 42 and the mixture so obtained passes along a mixture line 48 to a combustion chamber 50. At the entrance to the combustion chamber 50, the line 48 is provided with a non-return valve 52. The combustion chamber 50 contains an inspection plug 54 to enable the interior of the combustion chamber 50 to be inspected if necessary. Further, the conduit 14 passes through the regulator 22 and then into the combustion chamber 50. As shown, the line 14 projects further into the combustion chamber 50 than the line 48, that is the line 14 has its exit downstream of the exit from the line 48. The combustion chamber 50 is also provided with a downstream tapered portion 56 having a fine nozzle 58 at its outer end. The line 48 contains an outlet valve (not shown) which, when opened allows flow of combustible gas-air mixture. The combustion chamber 50 has a transistorised ignitor OMPI box 60 mounted on it. The box 60' has a control means such as a button to enable it to be energised and a power supply such as a small battery. The box 60 is connected to a sparking plug 62 mounted in the combustion chamber 50, by means of an H.T. lead 64. The apparatus further comprises a bottle 66 arranged to contain a supply of liquid cleaner. The bottle is con¬ nected via a line 68 to the air inlet line 10 so that the contents of the bottle 66 are under pressure. Further, the bottle 66 has an outlet line 70" leading into the down¬ stream tapered portion 56 of the combustion chamber 50. The line 70 contains a tap 72 to control supply of liquid cleaner. The regulator 18 has a conduit 72 leading from its pas¬ sive side to the active side of the diaphragm 22, and a conduit 74 leading from its passive side to the active side of the diaphragm 20. A further conduit 76 leads from the passive side of the regulator 18 to an air pressure gauge 78 which indicates the regulated pressure of the air entering the mixing chamber 42 and the pressure of air in the conduits 72 and 74. A conduit 80 leads from the passive side of the regulator 20 to the active side of the regulator 18. A conduit 82 leads from the passive side of the regulator 20 to a gas pressure gauge 84. The gas pressure gauge 84 indicates the regulated gas pressure of the regulator 20 and the pressure in the conduit 80. In use, the regulators 18 and 20 are set to a particular desired regulated pressure by adjusting the positions of the spindles 26 by turning same in their threaded mountings. Thus, the pressure exerted on the diaphragms 30 by the springs 32 is adjusted. Preferably, the gas regulator 20 spindle is turned in slightly more than the air regulator 18 spindle so that the regulated gas pressure is always slightly higher than the regulated air pressure. To commence operation, the lines 10 and 12 are connected to sources of pressurised air and gas respectively. The line 14 is connected to a source of pressurised water such as the mains water supply. Valves in the water line 14 and air line 10 can be opened to allow the pressurised fluid to reach the regulators 18 and 22 respectively. A valve in the gas line 12 is then opened. The outlet valve in the line 48 is then opened to allow flow of combustible mixture through to a combustion chamber. The ignitor box 60 is energised to ignite the ' combustible mixture from the mixing chamber 42 and the line 48. Further, the regulated air pressure acts on the active side of the diaphragm of the regulator 22 through the line 72 so enabling water to pass along the line 14 into the combustion chamber 50. Further, the regulated air pressure acts on the active side of the diaphragm of the regulator 22 through the line 74. This means that the gas flow through the regulator 20 is increased to a -desired level under normal operating conditions. However, should the regulated air pressure fall for any reason, then the pressure acting on the diaphragm in the regulator 20 will also be decreased. Thus, the rate of gas flow is decreased. Thus, the com¬ bustible mixture remains at roughly the same composition even if the available air pressure falls. Also, if the air pressure falls, the pressure on the diaphragm in the regulator 22 decreases so that the amount of water passing to the combustion chamber 50 is lowered. Thus, the possiblility of a reduction in the amount of combustible mixture is compensated for by a fall in the amount of water supplied. There is also, the possibility of a fall in gas pressure O PI and so the regulated gas pressure is applied to the active side of the diaphragm of the regulator 18 by the conduit 80. Thus, if the regulated gas pressure falls below the desired level the regulated air pressure also falls to maintain the composition of the combust¬ ible mixture within useable limits. With the arrangement shown in Figure 1, a fall in gas pressure reduces pressure on the diaphragm of the regulator 18 and leads to a fall in air pressure. A fall in air pressure leads to a reduction in pressure on the diaphragms of the regulators 20 and 22 and so leads to a reduction in gas pressure and water pressure. Thus, a fall in gas pressure or air pressure will reduce all three pressures but a fall in water pressure will not affect the air and gas pressures. Thus, the arrange¬ ment is particularly useful in locations where the water pressure is reliable and does not fluctuate, but when the air pressure and/or gas pressure have a tendency to fluctuate. The regulator 22 contains no spring and is therefore closed completely until pressure is exerted from the regulator 18 along the conduit 72. The regulators 18 and .0 contain springs and so can be arranged so that initially low volumes can initially pass through them. Once the flow is established the pressures act on the active sides of the other diaphragms and the regulators are opened fully. The gas regulator 20 is usually ar¬ ranged to have a slightly higher applied spring pressure than the air pressure regulator 18 so that the regulated gas pressure always tends to be higher than the regulated air pressures. Similarly, since the regulator 22 contains no spring, the regulated air pressure tends to be higher than the regulated water pressure. Many other variations are possible within the general concept of the present invention. In Figures 3 to 10, the symbol G represents gas supply, the symbol ^ repre¬ sents air supply, the symbol W represents water supply and the symbol M represents supply of gas-air mixture. For example, in Figure 3 there is shown a schematic regu¬ lation system for a steam cleaner of the present invention in which the regulated gas pressure acts on the active side of the air regulator and the water regulator so that the latter two pressures drop correspondingly if there is a decrease in gas pressure. Also, the regulated air pressure acts on the active side of the gas regulator to drop the gas pressure if the air pressure drops. Once again the gas pressures are unaffected by water pressure and this arrangement is particularly useful when the gas pressure tends to fluctuate. The arrangement shown in Figure 4 , has the regulated water pressure acting on the air regulator while the regulated air pressure acts on the water regulator and the gas reg¬ ulator. This arrangement is particularly useful where there is a stable gas supply but where the water pressure and air pressure can fluctuate. The arrangement shown in Figure 5, is similar to that shown in Figure 4 except that the regulated gas pressure acts on the water regulator so that a drop in gas pres¬ sure would lower the water pressure but a drop in air pressure would not directly affect the water pressure. However, the water pressure would be indirectly affected by a drop in air pressure by the reduced air pressure acting on the gas regulator. With the arrangement shown in Figure 6, the regulated gas pressure acts on the air regulator, the regulated air pressure acts on the water regulator and the regulated water pressure acts on the gas regulator. Thus, a drop in any of the fluid pressures wo ' uld directly or indirectly lead to a corresponding drop in the other two fluid pressures. The arrangement shown in Figure 7 has the regulated water pressure acting on the air regulator and the gas regulator OλiPI while the regulated air pressure acts on the water regu¬ lator. Thus, a drop in water pressure leads directly to a drop in air and gas pressure while a drop in air pres¬ sure leads directly to a drop in water pressure but a drop in gas pressure would not affect the other pressures This arrangement is useful where air and water supplies are subject to fluctuations but when there is an assured gas supply. The arrangement shown in Figure 8 has the regulated air pressure acting on the gas and water regulators . A drop in air pressure would lead to a drop in gas and water pressures but a drop in gas pressure or water pressure would not affect other pressures. This arrangement is useful where there is an assured supply of gas and water but the air supply is subject to fluctuations. With the arrangement shown in Figure 9 the regulated air pressure acts on the gas regulator while the regulated gas pressure acts on the air regulator. This arrangement is useful where the air and gas supplies are subject to fluctuation but the water supply is reliable. In Figure 10, there is shown an arrangement where the regulated water pressure acts on the air and gas regu¬ lators. This arrangement is useful where the air and gas ON.PI VIPO supplies are reliable but the water supply is subject to fluctuation. In Figure 11, there is shown an arrangement where the regulated gas pressure acts on the air and water regu¬ lators. This arrangement is useful where the gas supply is subject to fluctuations but the air and water supplies are reliable. Modifications and variations such as would be apparent to a skilled addressee are deemed within the scope of the present invention. For example, the combustion chamber 50 could have another chamber in heat exchange relation to it which other chamber would have the water supply fed to it Also, the water regulators have been described without springs but it is to be understood that they can include springs or other means for adjusting the pressure on the diaphragm apart from fluid pressure.

Claims: CLAIMS 1. A steam cleaning apparatus comprising a combustion chamber having an inlet means arranged to be connected to a source of compressed air and a source of compressed combustible gas, and exhaust gas outlet means, a further inlet means arranged to be connected to a supply of water, said further inlet means being arranged to supply water to a heat receiving location in or adjacent to the combustion chamber so that the water can be heated by combustion of the air and combustible gas, said apparatus further comprising a respective supply line for gas, air and water and each supply line containing a fluid pressure regulator having an active side and a passive side, characterised in that inter-regulator conduit means is provided for applying the regulated fluid pressure from the passive side or sides of one or more regulators to the active sides of at least two regulators. 2. - A steam cleaning apparatus according to Claim 1, characterised in that an inter-regulator conduit extends from the passive side of_ the air regulator to the active side of the gas regulator and an inter- regulator conduit extends from the passive side of the gas regulator to the active side of the air regulator. 3. A steam cleaning apparatus according to Claim 2, characterised in that there is an additional ~ inter-regulator conduit extending from the passive side of the air and gas regulator to the active side of the water regulator. 4. A steam cleaning apparatus according to Claim 1, characterised in that there is an inter-regulator conduit extending from the passive side of the air regulator to the active side of the water regulator and an inter- regulator conduit extending from the passive side of the water regulator to the active side of the air regulator. 5. A steam cleaning apparatus according to Claim 4, characterised in that there is an additional inter- regulator conduit extending from the passive side cf the air regulator to the active side of the gas regulator. 6. A steam cleaning apparatus according to Claim 1, characterised in that an inter-regulator conduit extends from the passive side of the gas regulator to the active side of the water regulator and an inter-regulator conduit extends from the passive side of the water regulator to the active side of the air regulator. 7. A steam cleaning apparatus ^ according to Claim 6, characterised- in that there is an additional inter- regulator conduit extending from the passive side of the air regulator to the active side of the gas " regulator. 8. A steam cleaning apparatus according to Claim 1, characterised in that there is an inter-regulator conduit OMPI extending from the passive side of the gas regulator to the active side of the air regulator and an inter-regulator conduit extending from the passive side of the air regulator to the active side of the water regulator. 9. A steam cleaning apparatus according to Claim 8, in which there is an additional inter-regulator conduit • extending from the passive side of the water regulator to the active side of the gas regulator. 10. A steam cleaning apparatus according to Claim 1, characterised in that there is an inter-regulator conduit extending from the passive side of the water regulator to the active sides of the air and gas regulators. 11. A steam cleaning apparatus according to Claim 10, characterised in that there is an additional inter- regulator conduit extending from the passive side of the air regulator to the active side of the water regulator. 12. A steam cleaning apparatus according to Claim 1, characterised in that the regulators contain diaphragms and at least the air and gas .regulators containing mechanical means for applying pressure to the diaphragms. OMPI

Inventors: MUNTZ SAMUEL HENDRIK, MUNTZ, SAMUEL, HENDRIK
Applicants: MUNTZ SAMUEL HENDRIK, MUNTZ, SAMUEL, HENDRIK
Application year: 1983
Main classification: F23N5
IPC codes: B08B3