JPS5938871B2 - Apparatus and method for reducing wastage of welding gas - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates primarily to methods and apparatus for welding, and more particularly to methods and apparatus for reducing the amount of inert gas consumed during welding operations.

The present invention is disclosed in U.S. Patent Application No. 1, filed March 17, 1980.
No. 30,706 and U.S. Patent Application No. 909,448, filed May 25, 1978.

Welding systems (e.g., MIG or TIG) may consist of a single welding station with its own welding gas supply, or may derive all gases from the same remote high-pressure gas source for use in larger welding shops. It can consist of a multi-strand welding station supplied with

In remote systems, main gas lines or headers run from the gas source to the various welding stations, whereupon drop (DrOp) lines run from there to the actual welding equipment. The invention is applicable to both types of welding systems.
In both systems, the gas is stored at a relatively high pressure and typically includes a pressure regulator in the outlet line from the reservoir so that the gas at the regulated pressure is supplied to one or more stations. It can be done.

In the past, it was common, or even necessary, to have a relatively high pressure of the welding gas downstream of the pressure regulator so that sufficient gas was available at all welding stations.

For example, such a pressure is approximately 45 psi (3.16
3K2/CTl'). This high pressure creates problems. At such high static pressures, when the actuator or trigger of the gas nozzle is initially depressed, a high static pressure is created in the line, causing a high flow of gas to exit the nozzle. The amount of gas exhausted is significantly greater than that required under transition welding conditions. This problem,
This cannot be solved by simply adjusting the pressure regulator to reduce the pressure, or in the case of remote systems, simply installing a second pressure regulator in each drop line to reduce the pressure in that line. Nor can it be solved by lowering it.

There are limitations on the amount that the pressure can be reduced and the amount that sufficient gas flow can be provided to the welding equipment to perform the necessary welding operations under both transition and steady state conditions. Thus, if the pressure regulator is adjusted to reduce the pressure so that exactly the optimum flow of gas is provided during steady-state welding conditions, the flow during transition conditions will be insufficient. . Moreover, if the gas pressure is reduced by a pressure regulator to provide optimal gas flow under transient conditions, gas will be in excess or wasted during steady state conditions. Therefore, the main object of the invention is to substantially reduce wastage of welding gas and to
Provides a means to separately control the gases supplied to the nozzle to achieve near-optimal gas flow at the nozzle to meet both transition-state and steady-state requirements, and to minimize gas wastage. An object of the present invention is to provide an improved method and apparatus.

According to the invention, a pressure regulator is installed in the gas line in combination with a surge tank at each welding station, in addition to and separate from the pressure regulator typically used in welding systems. to substantially reduce the pressure in the line.

In the case of remote installations, there is a pressure regulator and surge tank in each drop line. The surge tank is located at the outlet of the pressure regulator such that the outlet of the pressure regulator communicates with the inlet of the surge tank. A flow restriction means is placed between the outlet of the regulator and the inlet of the surge tank. The outlet of the surge tank communicates with the welding equipment. The purpose of the surge tank is to provide a low pressure gas reservoir between the regulator and the welding equipment. During the transition period, the surge tank
It functions to provide a gas flow greater than that supplied to the welding equipment during steady state operation. This tank thus serves to provide a "surge" of gas when the welding operation is started. The purpose of the flow restriction means is to increase or increase the pressure drop across the surge tank during the transition period, thus increasing the flow of gas. or to increase the surge above what it would be in the absence of limiting means.The objective is to efficiently meet the gas requirements under both transition and steady state conditions without waste. That's true.

Thus, at low pressures set to provide an adequate flow of gas under steady state conditions, the volume of the flow restriction means and surge tank is such that the amount of gas contained therein under low pressure, quiescent conditions is It should be such that it is sufficient to provide an adequate flow of gas during the transition period. The result is a significant reduction in gas wastage and correspondingly significant economic savings.

In a preferred embodiment of the invention, the components of the device,
For example, pressure gauges, pressure regulators, flow restriction means, and surge tanks are placed in sealed housings to prevent tampering.

This ensures that once the equipment is adjusted to function in the most efficient manner, it remains that way and is not tampered with by the welding operator. Thus, it is another object of the present invention to be economical in manufacture, durable in use, easily adjusted to the optimum efficiency of each welding station, and yet free from tinkering with its components once adjusted. It is an object of the present invention to provide a device that is easy to seal so as to prevent the problem from occurring. According to a preferred embodiment of the invention, the pressure gauge is externally visible on one side of the housing.

The key-operated lock selectively closes an opening in one side of the housing to allow pressure adjustment only when the lock is removed from the housing, thereby exposing the regulator's pressure adjustment screw. Make it possible to adjust the equipment. Referring to the drawings, numeral 10 represents a high pressure welding gas source.

This gas source 10 is connected via a gas line 11 to a pressure regulator 12.
connected to. Pressure regulator 12 is typically included in common welding systems. The outlet of the pressure regulator 12 passes through a line 13 to a gas control device 14 which is the subject of the present invention.
connected to. The outlet of the gas control device 14 is line 1
5 to a welding device 16 of a typical welding station. Examples of welding systems to which the present invention pertains include:
A metal inert gas (MIG) welding system and a tungsten inert gas (TXG) welding system, each welding system containing a sheath valve to prevent gas flow when welding is not in progress. Control device 14 in this preferred embodiment generally comprises a housing formed from housing members 82 and 84. Housing members 82 and 84 are welded together. Housing member 82 has an upper portion 86 and side portions 88 and 90 extending downwardly therefrom.
including. Housing member 84 has a lower portion and a rear wall 94 and a front wall 96 extending upwardly therefrom. Mounting 100 is located at the rear of the device and is placed in communication with line 13.

Mounting 100 is connected to the input of an adjustable pressure regulator 104 that includes an adjustment screw 106. Pressure regulator 10
4 delivers an outlet pressure of approximately 0 to 15 psi (0 to 1.05 Ky/?) at an inlet pressure of less than 350 ps1 (24.5 K2/CTl), and said low outlet pressure at a time that meets welding requirements. remain constant across the board. The outlet of pressure regulator 104 communicates with T-fitting 108 . T
Mounting 108 includes pressure gauge 110 and surge tank 112
communicate with the entrance. The pressure gauge is preferably O~30psi
(0 to 2.109 Ky/CTI). Installation 1
14 is arranged to communicate with the outlet side of the surge tank 112 and with a line 15 extending to a wire supply device or welding device 16. Further according to the invention, flow restriction means 117 are installed in the mounting 108 at the mounting connection to the surge tank.

This restriction means is circular in cross-section and shaped as shown in FIGS. 7 and 8 to snap into the mounting connection. The restriction means is a sintered mass, preferably of bronze, which is thus porous and capable of restricting the flow of gas. By way of example, the restriction means 117 can have a diameter of about 0.25 inches (2.75 cm) at its small end. The restriction means is capable of allowing sufficient gas to flow at low pressures to meet steady state requirements while simultaneously providing a pressure drop across the surge tank that is greater than the pressure drop in the absence of the restriction means and meeting transition requirements. to satisfy. As best shown in FIG. 3, face 118 of pressure gauge 110 is visible from the outside at the front of the housing.

A key-operated lock 120 is mounted at the front of the housing and includes a barrel 122. This barrel 122
can be removed from lock 120 when key 124 is used. Support 126 extends from lock 120 to pressure regulator 10, as best illustrated in FIG.
Extends to 4. Thus, once the barrel 122 is in place within the lock 120 and the key 124 is removed therefrom, access to the pressure adjustment screw 106 is prevented. However, once barrel 122 is removed from lock 120, pressure adjustment screw 106 can be turned by simply inserting a screwdriver, as seen in FIG. Thus, the described embodiment provides a self-contained solution for the device of the invention that is relatively inexpensive, durable, and prevents tampering with unit components, while at the same time facilitating adjustment by experts. A containment sealed unit device is provided.

This unit also facilitates connection to the gas line at each welding station. Theory of Operation There is no need to describe or even know the theory of operation of the present invention; it is sufficient that the apparatus and method of the present invention solve the problem and achieve the intended results. However, the theory of operation is believed to be as follows: if the gas flow required under transition conditions (when first activating the welding equipment, such as when depressing the trigger of a gas nozzle), the flow of gas required under steady-state conditions greater than the gas flow required during the condition (continuous welding after transition conditions).

It is believed that the reason for requiring this additional flow of gas during transition conditions is that when the welding equipment is shut down, air enters through the nozzle and partially into the gas line. This air must be rapidly paged and replaced with inert gas to produce a high quality weld. It is also important to displace the air in the weld zone of the workpiece at the beginning of welding. Curve A in FIG. 6 shows the optimal gas flow from the welding equipment versus time.

The time O-T1 is a transition period. The time after T1 is a steady state period. As shown by curve A, the gas flow required for proper welding during transition conditions is higher than during steady state conditions. Compared to curve A, curve B shows the gas flow from the welding equipment of a conventional welding system that does not include the control device of the present invention, and curve C shows the welding of a welding system that does not include a surge tank but only includes a regulator. Shows gas flow from the device.

These curves show that with a conventional system there is significant waste of gas during the transition period, as shown in curve B, but with the regulator alone, without a surge tank, as shown in curve C. Gas flow during the transition period is insufficient so that the As explained above, the main objective of the present invention is to provide sufficient gas flow from initial state (TO) through steady state without wasting gas.

In other words, the main objective of the invention is to get as close to curve A as possible. The present invention achieves this objective. Since the temperature change in the gas during the transition flow can be ignored and is ignored for the purposes of this analysis, ignoring temperature, Paul's law becomes: where P1 and P2 are absolute pressures. , where V1 is the volume of gas in the surge tank at static pressure and P1 is T.

is the static pressure in the surge tank at T1, P2 is the pressure in the surge tank at T1, and V2 is P1
is the effective volume of gas in the surge tank caused by the pressure change from P2 to P2. In other words, the pressure changes from P1 to P2
, the effective volume of gas in the surge tank increases. Alternatively, stated another way, the actual amount (weight) of gas in the surge tank decreases during the transition period.
The change in this quantity can be expressed as V2-V1 or ΔV, and T in curve A of FIG. From T
1, there is a surge or additional flow of gas required for proper welding during the transition period. Also,
It will be seen that the larger the factor P1/P2, the larger ΔV.

Flow restriction measures increased this factor and thus increased the surge during the transition period at low static pressure. Once steady state conditions are reached, there is no appreciable pressure drop across the surge tank, so P1 becomes P2
and V1 is equal to 2.

In other words, there is no excessive gas loss during steady state welding since the surge or increased flow of gas is only provided during the transition period. The volume of the surge tank and the pressure of the gas in the surge tank under quiescent conditions and the flow restriction means are chosen to create a gas flow that closely approximates the transient and steady state requirements. Thus, the surge tank has a sufficiently large volume to adequately gas the gas without undue wastage during transition conditions, and a low enough resting pressure to minimize gas wastage during steady-state conditions. should be. Various changes and modifications can be made to the present invention, as will be apparent to those skilled in the art. However, these changes or modifications are included within the teachings of this disclosure and the invention is limited only by the scope of the claims.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a typical welding shop layout. FIG. 2 is a perspective view of the apparatus of the preferred embodiment of the invention with a portion of the housing removed to better illustrate the invention. 3 is a front view of the apparatus of FIG. 2; FIG. FIG. 4 is a cross-sectional view of the device taken along line 4--4 of FIG. 3, with the dashed line indicating the lock removed therefrom.
FIG. 5 is a cross-sectional view taken along line 5--5 of FIG. 6th
The figure shows gas flow curves from initial to steady state conditions that approximate optimal flow requirements for efficient operation. FIG. 7 is an installation diagram showing in broken lines the flow restriction means according to the invention; 8 is a side view of the flow restriction means of FIG. 7; FIG. 10... High pressure welding gas source, 11.
...Gas line, 12...Gas regulator,
13... line, 14... gas control device, 15... line, 16... welding device, 82... housing member, 84・・・・・・
・Housing member, 86... Upper part, 88...
...Side part, 90...Side part, 92...
Lower part, 94... Rear wall, 96... Front wall,
100... Installation, 104... Adjustable regulator, 106... Adjustment screw, 108...
...T mounting, 110...Pressure gauge, 112
... Surge tank, 114 ... Installation, 117 ... Flow restriction means, 118 ...
・Screen, 120...Key operation lock, 122...
... Barrel, 124 ... Key 126 ...
...Support.

Claims (1)

Claims: 1. A gas discharge system comprising one or more gas consumption stations, each station connected through a gas line to a source of high pressure gas, and further comprising a control device therein, the control device comprising: a pressure regulator connected in a gas line to a gas consumption station for substantially reducing the pressure of the gas at an outlet of the pressure regulator; an inlet in fluid communication with the outlet of the pressure regulator; surge tank means having an outlet in fluid communication, whereby the flow of gas discharged at the reduced pressure from the controller to the station is controlled during a transition period immediately after operation of the station. during steady-state operating conditions. 2. A patent further comprising a housing having said pressure regulator disposed therein, and means for selectively permitting access to said regulator for adjusting said regulator and preventing tampering thereof by non-experts. A control device according to claim 1. 3. The control device according to claim 2, wherein the surge tank is located within the housing. 4. The control device according to claim 3, wherein said selective access means is a key operated closure. 5. The selective access means further includes a closure operable between a locked/closed position and an open position to form an opening in the housing with the closure in an open position, the opening being operable to form an opening in the housing. 4. A control device according to claim 3, which allows insertion of an adjusting device for adjusting the device. 6. The control device of claim 3 further comprising a pressure gauge in fluid communication with the outlet of the regulator. 7. The pressure gauge is installed within the housing,
7. A control device as claimed in claim 6, readable on the outside of the housing when the housing is closed. 8. The control device according to claim 7, wherein the pressure gauge is installed in a wall of the housing so that its surface can be exposed to the outside and read. 9. The control device according to any one of claims 1 to 8, further comprising flow control means between the pressure regulator and the surge tank.