Patent Application
20130089825
1. Field of the Invention
Devices, systems, and methods consistent with the present invention relate to a torch and more particularly to an improved swirl combustion air fuel torch.
2. Description of the Related Art
Gas torches are used to combine air with a combustible fuel. The torches attempt to combine the air with the fuel to create an appropriate mixture ratio to provide a heating or cutting flame which is then used to heat or cut through materials such as metal. However, because of various factors, such as different fuel types and densities, flow rates, etc. it can be difficult to provide a torch which optimizes the fuel/air mixture to provide a stable and optimal flame.
An exemplary embodiment of the present invention is a torch, having a torch body having an upstream cavity, a mixture cavity and a tube connection portion downstream of the mixture cavity. The mixture cavity has a plurality of conical bores through a sidewall of the mixture cavity to permit a flow of air into the mixture cavity, and the tube connection portion has a bore to receive a flow from the mixture cavity and direct the flow to an exit of said tube connection portion. A tip orifice structure is inserted into the upstream cavity and the tip orifice structure has a bore through a center thereof. The bore has a first diameter and the bore directs a fuel to the mixture cavity. A tube is coupled to the tube connection portion which receives the flow from the tube connection portion, and has a inner diameter. The tube delivers the flow to a flame and the the ratio of the first diameter to the inner diameter of the tube is in the range of 5 to 7% for acetylene torches and 2 to 3% for propane and propylene torches.
The above and/or other aspects of the invention will be more apparent by describing in detail exemplary embodiments of the invention with reference to the accompanying drawings, in which:
Exemplary embodiments of the invention will now be described below by reference to the attached Figures. The described exemplary embodiments are intended to assist the understanding of the invention, and are not intended to limit the scope of the invention in any way. Like reference numerals refer to like elements throughout.
FIG. 1A/1B is a diagrammatical representation of a torch 100 in accordance with an exemplary embodiment of the present invention. The torch 100 is made up of a number of components, primarily including a tip tube 101; a torch body 103, a tip orifice 107, and a swirl tip insert 112. Each of these components will be discussed in turn.
The tip orifice 107 is a brass insert which is to be inserted into a cavity 110 in the torch body 103. The orifice 107 can be made of a metallic material such as brass. The tip orifice 107 can also have a threaded section 108 which allows the orifice 107 to be securely inserted into the body 103. Through the centerline of the tip orifice 107 an inlet bore 109 is provided. The bore 109 has a constant diameter along its length and a cylindrical shape. Based on the application for the torch 100 the bore can have different diameters. That is, for some operations a smaller bore 109 is needed while for other operations a larger bore 109 is needed. The bore should be made as smooth as possible so as to ensure smooth gas flow through the bore 109. In exemplary embodiments, the bore can have a diameter in the range of 0.007 to 0.04 inches.
The body 103 can also be made from brass and has a cavity 110 which allows for the proper seating of the tip orifice 107. This seating should be such that no gas can escape from the connection. An o-ring can be used to ensure an adequate seal is provided. Along the centerline of the body 103 is a bore 114 which allows for the flow of gas from the tip orifice 107 to pass through the body 103 to an inner cavity 113 in the body 103 and into the tube 101. The bore 114 is comprised of an upstream portion 114A and a downstream portion 114B which are separated by the cavity 113. In an exemplary embodiment of the present invention, the upstream portion 114A has a first diameter and the downstream portion 114B has a second diameter which is larger than the first diameter. In an exemplary embodiment, the upstream portion 114A has a diameter which is the same as the diameter of the bore 109 in the tip orifice. In a further exemplary embodiment, the upstream portion 114A has a diameter which is slightly larger than that of the bore 109. However, the diameter differential should not be so much as to adversely affect the flow of gas from the bore 109 into the cavity 113.
In exemplary embodiments of the present invention used with acetylene fuel the bore 109 has a constant diameter in the range of 0.01 to 0.04 inches. In exemplary embodiments of the present invention used with either propane or propylene fuel the bore 109 has a constant diameter in the range of 0.007 to 0.02 inches.
In another exemplary embodiment, the cavity 113 is sized such that the bore 109 of the tip orifice 107 directly delivers the fuel to the cavity 113, in that there is no upstream portion 114A of the bore 114. Rather the cavities 110 and 113 are sized such that the downstream tip of the tip orifice 107 directly contacts the cavity 113.
The body 103 has a first connection end 106 which connects to a gas supply line (not shown) which is typically connected to a gas supply source (also not shown). The first connection 106 can be of any known type of connection to allow for the body 103 to be properly secured to a gas supply line. In an exemplary embodiment of the present invention, the connection 106 is a “quick-type” connection end which allows for the quick release and connection of the body. Such a connection uses a slidable collar and a pressure fitting such that when the end 106 is inserted into the supply line a hermetic seal is provided to prevent gas from flowing through the joint. Such a connection type is generally known and need not be described in detail herein. On the sides of the body 103 are at least four conically shape bores 104 which all extend from an outer surface of the body 103 to an inner cavity 113. In the embodiment in which there are four bores 104, they are each positioned 90 degrees from each other radially. This inner cavity 113 couples the upstream and downstream portions 114A/114B of the bore 114 with the conically shaped bores 104 on the sides of the body 103.
During use of the torch 100, a fuel gas is provided from a source through a hose to the body 103. The gas then flows through the bore 109 in the tip orifice 107 into the upstream portion 114A of the bore 114 in the body 103. As the gas then flows into the cavity 113 towards the downstream portion 114B of the bore 114 it creates a venturi effect at the conical bores 104 which causes the atmosphere to be drawn in through the conical bores and into the cavity 113. Thus, in the cavity 113 a mixture of fuel and atmosphere is created. This mixture then passes down through the downstream portion 114B of the bore 114 and into the tube 101. The body 103 has a tube connection portion 102 which allows for the connection between the body 103 and the tube 101. This connection can be made in any number of ways, including a friction fit, a threaded connection, or the like. However, the connection should be also hermetic such that the mixture of fuel and atmosphere does not escape from the connection point. The downstream portion 1148 should have a sufficient diameter to deliver the combined volume of the atmosphere and fuel without restricting the flow of the mixture. All of the bores and cavities in the body are to be as smooth as possible so as to provide smooth surfaces for fuel and atmosphere flow.
The tube 101 can be made of a stainless steel material, as well as other metals which are capable of withstanding high temperatures. The tube 101 has an inside diameter ID which is selected for the appropriate operation. That is, a higher flow rate of mixture will require a larger diameter ID. The inside diameter ID is to be constant along the length of the tube 101 and should be a smooth surface to provide for optimal flow. The diameter ID can be in the range of 0.2 to 0.7 inches.
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It has been discovered, unexpectedly, that the ratio of the diameter of the bore 109 in the tip orifice 107 to the inside diameter ID of the tube 101 is important to the optimal operation of the torch 100. This ratio has not been previously appreciated or understood. Furthermore, it has been discovered that this ratio is dependant upon the type of fuel being employed for the operation. For example, this ratio depends on whether or not the fuel used is acetylene or propane and propylene. This will be explained more fully below.
It has been discovered that, in exemplary embodiments of the invention, if the torch 100 is to be used with acetylene fuel the ratio of the bore 109 diameter to the inside diameter of the tube should be in the range of 5 to 7%. In further exemplary embodiments to be used with acetylene it has been discovered that the ratio should be in the range of 5.4 to 6.6%. However, for torches to be used with either propane or propylene fuel exemplary embodiments are to have a ratio in the range of 2 to 3%. In further exemplary embodiments using propane or propylene the ratio is in the range of 2.5 to 3%. It has been discovered that these ratios, for the appropriate fuel, provide surprisingly improved performance. It has also been discovered that the ratio is dependant on the type of fuel to be used, as indicated above.
For example, if an exemplary torch 100 is to be used with acetylene fuel and the inside diameter ID of the tube 101 is ¼″, the diameter of the bore 109 in the tip orifice should be in the range of 0.0125″ to 0.0175″ (5 to 7%). However, if the exemplary torch is to be used with propane or propylene the diameter of the bore 109 is to be in the range of 0.005″ to 0.0075″ (2 to 3%). By maintaining these respective ratios, optimal performance can be achieved for the torch.
With these ratios, exemplary embodiments of the torch 100, used with acetylene, can provide overall mixture flow rates in the range of 2 to 30 SCFH (standard cubic foot per hour) at a fuel pressure of 14 PSI, while still provide an optimal flame. Similarly, in exemplary embodiments used with propane or propylene a flow rate in the range of 2 to 12 SCFH can be achieved at a fuel pressure of 28 PSI, while still providing an optimal flame. Of course, it is understood that larger flow rates are achieved by using a larger diameter tube 101 and bore 109. The ratios discussed above allow for an optimal flow and mixing of the atmosphere (e.g., air) with the fuel to achieve an optimal flame.
While the invention has been particularly shown and described with reference to exemplary embodiments thereof, the invention is not limited to these embodiments. It will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the following claims.
