WO2002047845A1

WO2002047845A1 - An arrangement for pressure regulation of exhaust fumes when welding or soldering chains

Info

Publication number: WO2002047845A1
Application number: PCT/SE2001/002730
Authority: WO
Inventors: Hans Gustav Erik Wahlbeck
Original assignee: Hans Gustav Erik Wahlbeck
Priority date: 2000-12-11
Filing date: 2001-12-10
Publication date: 2002-06-20
Also published as: AU2002222854A1; SE0004570D0; SE518022C2; SE0004570L

Abstract

The invention relates to a gas pressure regulating arrangement (90), which comprises a practically closed chamber or space (91), wherein said chamber includes at least one inlet port (91a), for receiving a chain extension consisting of a series of open links, an outlet port (91b), for a chain whose links have been closed by welding or soldering, and an outlet (91c), for the exit of exhaust gases occurring in said chamber. Located in the closed chamber (91) is at least one link-welding or link-soldering arrangement (31), to which the gas or gases, such as acetylene and oxygen is/are delivered for welding or soldering process. Combustion of the gases is controlled so as to take place under reducing conditions, i.e. with anoxygen-gas deficiency. The link-welding or link-soldering arrangement (31) has the form of a tunnel positioned over an underlying structure (3), which supports the chain extension and the chain. The surface of the tunnel (31), that faces towrads the supporting structure, is caused to define a narrow gap ('s') with the planar surface (3) of said structure. There is applied to the exhaust gases generated in the tunnel 831) a pressure (T1), which exceeds the pressure (T2) surrounding the tunnel (31) a pressure (T1), which exceeds the pressure (T2) surrounding the tunnel (31) and th epressure in the chamber (91), thereby creating conditions for an adapted passage of exhaust gas from the tunnel interior (31) to said chamber (91).

Description

AN ARRANGEMENT FOR PRESSURE REGULATION OF EXHAUST FUMES WHEN WELDING OR SOLDERING CHAINS

Field of invention The present invention relates generally to a gas pressure regulating arrangement for pressure regulation of exhaust gases when welding or soldering chains, i.e. in the absence of residual gaseous oxygen that is liable to oxidise the material used, after combustion.

In this regard, the invention relates to a gas pressure regulating arrange- ment that comprises an at least practically closed chamber, which shall at least include one inlet port, adapted to receive a chain extension that consists of a series of open links, one outlet port, for a chain that consists of a series of links which have been closed by welding or soldering the open links, and an outlet for exhaust gases occurring in said chamber, wherein said closed chamber contains at least one link-welding and/or link-soldering device, to which there is supplied a gas or typically a mixture of different gases, such as acetylene and oxygen or oxygen gas for welding or soldering purposes, wherein combustion of these gases is controlled to take place in a reducing atmosphere, i.e. with an oxygen deficiency, wherein said link-welding or link-soldering device has the form of a tunnel, which is orien- tated over an underlying supportive element, that supports the chain extension and the chain.

The present invention has been developed for the use in a production line of the kind in which there is used a rotatable disc or table and a number of peripherally related working stations, situated completely or partially above the upper surface of the disc.

There is fed to the edge region of the disc a series of to a chain co-ordinated open links, which are in the form of a chain extension and which links are closed by welds to form the chain, said open links being loosely interconnected and lying freely in relation to each other prior to the event when said open links being closed by welds in a link-welding device.

Description of the background art

With regard to the earlier known standpoint of techniques relating to a production line, particularly significant with respect to the present invention, refer- ence is made to the contents of an International Patent Application having the Serial Number PCT/SE83/00371 and allotted the International Patent Publication No. WO 84/01788.

This prior publication illustrates and describes a method and an arrange- ment for the production of non-allergenic objects, particularly objects formed from metals and intended for direct contact with the skin of a living creature, wherewith the present invention is also intended to fulfil these requirements.

In addition to chains of different kinds that have different link structures, examples of such objects include necklaces, ankle bracelets, wrist bracelets, ear- rings and/or nose rings, pieces of jewellery, watches, spectacles, etc., where completely pure metals, especially precious metals such as gold, silver, platinum, palladium, rhodium, are alloyed with optimally pure zinc, copper, aluminium, nickel or chromium, and where treatment processes carried out with the use of heating and cooling working stations are effected without access to air and without contact with surface reacting substances, such as salts or acids.

All heating and cooling processes are preferably carried out under the protection of a shielding gas. The arrangement illustrated in this prior publication utilises a production line for producing, from a series of co-ordinated open chain-links, a series of closed links, which together form a flexible chain. There is used in the production line a number of working stations that include; a first station, in which open links are placed in a co-ordination on a table, a second station, which closes the open links with welds to form closed links, a third station, which cools the newly welded links, and a fourth station, in which the cooled links are discharged from the production line. More particularly, it is said that, in order to enable the method to be carried out, the device shall comprise a rotatable table (61 ) for allowing a cold worked object (66), in the form of an open-link chain, to pass through a link-welding device (63) or channel while using a heating gas or a shielding gas (70), and a following link-cooling device (68), which uses the exhaust gases from the link-welding de- vice (63), said exhaust gases being conducted, through channels (71 , 73), as a cooling and a shielding gas during the cooling sequence, wherewith displacement of the object (66) in the cooling sequence takes place concurrently with the supply of cooling and shielding gas.

Fig. 7 of this prior publication can be considered significant with respect to the earlier standpoint of techniques in respect of the present invention.

Summary of the present invention

Technical problems When taking into consideration the technical deliberations as a person skilled in this particular art must make in order to provide a solution to one or more technical problems that he/she encounters, it will be seen that on the one hand it is necessary initially to realise the measures and/or the sequence of measures that must be undertaken to this end, and on the other hand to realise which means is/are required in solving one or more of said problems. On this basis, it will be evident that the technical problems listed below are highly relevant to the development of the present invention.

When considering the earlier standpoint of techniques, as described above, it will be seen that a technical problem resides in the ability to create condi- tions which enable an applied welding process and/or soldering process to be effected readily with the aid of simple means and in an atmosphere or environment that is free from oxygen, so as to prevent oxidation of individual links.

A technical problem resides in the ability to realise the significance of and the advantages afforded by creating a unique co-ordination of different elements and a number of exhaust gas treatment systems, in which requisite pressure differences have been taken into consideration and can be readily regulated.

In this regard, a technical problem resides in the ability to realise the significance of and the advantages afforded by adapting the welding and/or soldering functions, that include a tunnel surface, which faces towards said underlying sup- portive surface and which defines a narrow gap with an underlying supportive surface, to apply to exhaust gases, deriving from the welding process, a pressure that exceeds the pressure surrounding the tunnel and associated with said chamber, thereby having created conditions for an adapted exhaust gas passage from the tunnel interior to said chamber, said passage being narrow but nevertheless suffi- cient for the purpose intended.

Another technical problem resides in the ability to realise the significance of and the advantages afforded by enabling a first fan device or corresponding device, connected to said chamber for evacuating exhaust gases therefrom, to be controlled in a manner to maintain the chamber pressure slightly above the pres- sure caused around said chamber.

Another technical problem resides in the ability to realise the significance of and the advantages afforded by enabling a second fan device or corresponding device, connected to the tunnel and evacuating exhaust gases therefrom, to be controlled in a manner to keep the tunnel pressure slightly above the chamber pressure.

Another technical problem resides in the ability to realise the significance of and the advantages afforded by allowing an accepted pressure difference to lie at least beneath 10 mm H₂O (water column). A further technical problem resides in the ability to realise the significance of and the advantages afforded by choosing a pressure difference of between 1 and 3 mm H O in practice.

In respect of the aforesaid pressure difference, a further technical problem resides in the ability to realise the significance of and the advantages afforded by providing, between the tunnel and the chamber, a gap that is smaller than 0.3 mm.

A further technical problem resides in the ability to realise the significance of and the advantages afforded by allowing said gap to have, more practically, an extension or opening of between 0.05 and 0.1 mm.

A further technical problem resides in the ability to realise the significance of and the advantages afforded by enabling the rotational speed of each fan device used to be regulated in dependence of a pressure-difference detecting sensor, with higher speeds at higher pressure differences.

A technical problem also resides in the ability to realise the significance of and the advantages afforded by enabling an input port for open links to be adapt- ed, via adjustment of a number of port portions, to present to the open-link chain extension one or more gaps that are narrower than 0.4 mm.

Another technical problem resides in the ability to realise the significance of and the advantages associated with enabling said input port to be adapted, via adjustment of a number of port portions, to present to outer surface parts of the open-link chain extension one or more narrow openings of between 0.1 to 0.2 mm.

Another technical problem resides in the ability to realise the significance of and the advantages afforded by enabling said output port to be adapted, via adjustment of a number of port portions, to present to outer surface parts of the closed-link chain one or more narrow openings of less than 0.4 mm. Yet another technical problem resides in the ability to realise the significance of and the advantages afforded by enabling said output port to be adapted, via adjustment of a number of port portions, to present to the closed link chain one or more narrow openings of between 0.1 to 0.2 mm. A further technical problem resides in the ability to realise the significance of and the advantages associated with passing the exhaust gases, evacuated from the tunnel, through a gas cooling heat exchange unit.

Still another technical problem resides in the ability to realise the significance of and the advantages afforded by allowing the gas-cooling process to con- tinue until the temperature of the gases is at least below 10°C and preferably about 0°C or lower.

Another technical problem resides in the ability to realise the significance of and the advantages afforded by providing, downstream of the heat exchange unit, a fan device or corresponding device that functions to regulate the tunnel pressure.

In addition, a technical problem resides in the ability to realise the significance of and the advantages afforded by positioning, downstream of said fan device or corresponding device, a valve arrangement that can be controlled to obtain a desired pressure in the closed-link chain cooling arrangement. Another technical problem resides in the ability to realise the significance of and the advantages afforded by deflecting gas surplus to said chamber and part of said surplus to the chain and its closed-links cooling arrangement, via said valve arrangement.

Another technical problem resides in the ability to realise the significance of and the advantages afforded by allowing said surplus part to be subjected to a rise in pressure, with the aid of a fan device or corresponding device, and preferably also a downstream cleaning filter.

In this regard, a technical problem resides in the ability to realise the significance of and the advantages afforded by allowing said surplus part to be sub- jected to a rise in pressure and to deliver it as a clean-blowing gas stream to a temperature sensor.

Another technical problem resides in the ability to realise the significance of and the advantages associated with allowing said surplus part, whose pressure has been raised to be delivered as a clean-blowing gas stream to a wheel ar- rangement, adapted for displacing and cooling a closed-link chain.

Another technical problem resides in the ability to realise the significance of and the advantages afforded by delivering the surplus, that has been subjected to a rise in pressure as a clean-blowing air stream, to a sensor that functions as a flame monitor.

A further technical problem resides in the ability to realise the significance of and the advantages associated with passing said gas surplus, that has been subjected to a rise in pressure, as a clean-blowing air stream to a sensor that includes a mirror, a lens protector or corresponding means. Still another technical problem resides in the ability to realise the significance of and the advantages associated with causing the clean-blowing air stream to pass through a constriction, preferably an adjustable constriction.

Yet another technical problem resides in the ability to realise the significance of and the advantages afforded by passing a part of said gas surplus to said chamber, via a constriction, for instance.

A further technical problem resides in the ability to realise the significance of and the advantages afforded by causing said divided part of the gas surplus to be delivered to said chain and its closed-link cooling device at an overpressure above the chamber pressure. In addition, a technical problem resides in the ability to realise the significance of and the advantages afforded by enabling the pressure in the chain and closed-link cooling device to be adjusted to a value above the chamber pressure, via a valve means that functions to this end.

A further technical problem resides in the ability to realise the significance of and the advantages afforded by designing one or more of said fan devices to function via an ejector effect.

A technical problem also resides in the ability to realise the significance of and the advantages afforded by allowing the combustion process with an oxygen- gas deficiency to be observed by an ocular perception of the colour of the flame, such as a yellowish colour. Alternatively, the combustion process, with an oxygen- gas deficiency, is observed by combusting evacuated exhaust gases freely in air.

Solution

The present invention relates to a gas pressure regulating arrangement and more particularly to one such arrangement that is designed for use in a chain production line.

In the case of this application, it is proposed, in accordance with the invention, that a gas pressure regulating arrangement is based on the use of a practical- ly closed chamber, which includes at least one inlet port, adapted for a chain extension consisting of a series of open links, an outlet port, adapted for a chain consisting of a series of links that have been closed by welding or soldering, and an outlet which enables occurring exhaust gases to be evacuated in the chamber in a controlled manner, wherein at least one link-welding or link-soldering device is placed in the closed chamber, wherein a gas or gas mixture, such as acetylene and oxygen (oxygen gas), required for the welding or soldering process, is delivered to said device, wherein combustion of such gases is regulated so as to take place under a reducing atmosphere, i.e. with an oxygen gas deficiency, and wherein said link-welding or link-soldering device has the form of a tunnel, posi- tioned over an underlying supportive structure that supports the chain extension and the chain.

With the intention of solving one or more of the aforesaid technical problems, it is proposed, in accordance with the present invention, that in the case of such an arrangement, the tunnel surface facing towards the underlying support is adapted to define a narrow gap with said support surface, that the exhaust gases generated by the welding and/or soldering process in said tunnel shall be given a pressure that exceeds the pressure surrounding said tunnel and said chamber, such as to have created conditions for an adapted and necessary passage of exhaust gas from the tunnel interior to said chamber. By way of proposed embodiments, that lie within the scope of the inventive concept, it is proposed that there is connected to the chamber a fan device or corresponding device, which functions to evacuate exhaust gases from the chamber, and that said fan device or corresponding device shall be controlled to maintain a chamber pressure slightly above the pressure surrounding said chamber. A fan device or corresponding device, connected to the tunnel and operative in evacuating exhaust gases therefrom, shall also be controlled to keep the tunnel pressure slightly above the chamber pressure.

According to the invention, the difference in pressure is less than 10 mm H₂O, such as between 1 and 3 mm H₂O (water column). The gap shall have an opening, a parallel-related opening, in the order of less than 0.3 mm, such as between 0.05 and 0.1 mm.

The rotary speed of the fan device is regulated in response to a pressure- difference sensor, with a control circuit that causes the fan device to rotate at higher speeds in response to higher pressure differences.

The input port is adapted to present one or more narrow openings to the edge surfaces of the open-link chain extension via adjustment to a number of port portions, said narrow openings having a height smaller than 0.4 mm, such as between 0.1 to 0.2 mm. The output port is adapted to present to the edge surfaces of the closed- link chain one or more narrow openings, having a height smaller than 0.4 mm, such as between 0.1 to 0.2 mm, by adjustment of a number of port portions.

Exhaust gases evacuated controllably from the tunnel are cooled, by passing said gases through a heat exchange unit. The gases are cooled to a low temperature, where practical deliberations require a temperature of about 0°C.

A fan device or corresponding device for regulating tunnel pressure is positioned downstream of the heat exchange unit.

Located downstream of the fan device or corresponding device is a valve arrangement, a three-way valve, for regulating a current exhaust gas-pressure in a device for cooling the chain and its closed links.

A part of a gas surplus is deflected to the chamber via the valve arrangement, and a part of said surplus is delivered to the device for cooling said chain and its closed links. The divided part of the gas surplus is subjected to a rise in pressure in a fan device or corresponding device and a filter-cleaning function.

The gas surplus, subjected to a rise in pressure, is delivered to a temperature sensor in the form of a clean-blowing gas stream.

The gas surplus, subjected to a rise in pressure, is delivered as a clean- blowing and cooling gas stream to a wheel arrangement, adapted for displacing and cooling a closed-link chain.

Said gas surplus, subjected to said rise in pressure, is delivered to a flame-monitoring sensor as a clean-blowing air stream.

Said gas surplus, subjected to said rise in pressure, is delivered as a clean-blowing air stream to a sensor that includes a mirror, a lens guard or corresponding means.

The clean-blowing air stream shall be caused to pass through a constriction, preferably an adjustable constriction. Any additional excess from said gas surplus is delivered to said chamber, via a constriction.

This divided portion of the surplus is delivered to the device for cooling said chain and its closed links at an overpressure above the chamber pressure.

The pressure around the chain and its closed-links cooling device is ad- justed to a pressure above the chamber pressure, through the medium of said three-way valve arrangement.

Alternatively, one or more of said fan devices may operate via an ejector effect.

The combustion process, with oxygen-gas efficiency, is determined by ocular perception of the colour of a flame, such as a yellowish colour, or by allowing exhaust gases to be combusted in the free air.

Advantages

Those advantages primarily afforded by an inventive gas pressure regulat- ing arrangement reside in the fact that conditions have been created which enable a link-welding and/or link soldering function to be carried out in a reducing environment, and also in the creation of conditions which enable a cooling function to take place in a reducing environment, wherein these reducing environments or atmospheres are created with exhaust gases, generated in link-welding and/or link-sold- ering processes.

By providing different exhaust gas pressures in different chambers or spaces in the production line, there are created conditions, which prevent the access of oxygen to the chain and therewith prevent oxidation and/or other colour changes.

The primary characteristic features of an inventive arrangement are set forth in the characterising clause of the accompanying claim 1. Brief description of the drawings

An embodiment of an arrangement at present preferred and having characteristic features significant of the present invention will now be described in more detail with reference to the accompanying drawings, in which; Figure 1 illustrates a production line that includes a number of working stations for producing a flexible closed-link chain from a series of to a chain co-ordinated open links, with the aid of a link-welding arrangement as a working station, among other things, Figure 2 is a more general view in perspective of a casing, belonging to the link-welding arrangement,

Figure 3 is a horizontal view of the casing of the link-welding arrangement, Figure 4 is an enlarged view of part of the fig. 3 arrangement and shows an end-wall opening for a series of to a chain co-ordinated open links, Figure 5 is a sectional view taken along the line V-V in fig. 3, which illustrates one out of a number of gas flames, which function to heat a weld location and which is included in a casing, having exhaust gas evacuating channels and gas-cooling channels, Figure 6 is an enlarged view of a lower part of a casing according to fig. 5, said part being provided with an exhaust-gas guiding lip, Figure 7 is a horizontal view corresponding to the horizontal view of fig. 3, and shows connections for a cooling medium and exhaust gas conducting system, Figure 8 is a principle block diagram illustrating certain parts of an arrangement-associated control unit, Figure 9 illustrates schematically a gas pressure regulating arrangement constructed in accordance with the principles of the invention, and Figure 10 illustrates parts of the fig. 9 arrangement in a slightly larger scale.

Description of an embodiment at present preferred It will be noted that in the following description of an exemplary embodiment at present preferred and having the significance characteristic features of the invention illustrated in the various figures of the accompanying drawings, there have been used particular terms and particular terminology with the primary intention of clarifying the inventive concept. However, the expressions and terms used shall not be seen as limiting the scope of the invention and it will be understood that each term chosen shall be interpreted to include all technical equivalents that function in the same or in essentially the same way, so as to be able to achieve the same or essentially the same intention and/or technical effect.

As shown in fig. 1 is a production line 1 , from which a chain 2, consisting of a series of closed links, can be produced from a number of to a chain co-ordinated links or an extension 2', consisting of a series of open links.

The series of open links, shown in fig. 1 , have been referenced 21', 22' and 23' respectively, whereas the closed links have been referenced 21 , 22, and 23.

The welds 21a, 22a in respective openings 21a', 22a' closing the links 21 , 22 are thus made in the link welding arrangement.

The open links 21 ', 22', 23' are fed down onto a flat upper surface 3' of a rotatable disc or table 3 at a position referenced 3a.

The downfeed of the chain co-ordination, consisting of open links 21', 22', 23', is illustrated and described in more detail in Swedish Patent Application No. 0003587-3, filed on October 4, 2000, the contents of which patent application shall be considered to form part of the instant application so as to make more apparent an appropriate use application of the present invention in a production line that includes mutually sequential working stations.

The open-link chain co-ordination 2' resting on the planar upper surface 3' of the disc 3 is transported, section by section, through a welding or soldering working station 31 , and a following cooling station 32, wherewith the chain, now consisting of closed links 21 , 22, 23, is advanced along a radius-related circular surface section 3b of the disc 3.

A link-welding arrangement will be described in more detail here below, this description having connection with the description in Swedish Patent Application No. 0004064-2, filed on November 7, 2000, with the title "Link-Welding Ar- rangement", wherewith the contents of said application shall be considered as forming part of the present application, so as to make more apparent an appropriate use application of the present invention in a production line that includes mutually sequential working stations.

A link-cooling arrangement is described and illustrated in more detail in Swedish Patent Application No. 0004065-9, filed on November 7, 2000, with the title "Link-Cooling Arrangement", wherewith the contents of said application shall be considered as forming part of the present application, so as to make more apparent an appropriate use application of the present invention in a production line that includes mutually sequential working stations.

There is also shown a heat-dissipating and closed-link-cooling arrangement referenced 32' in fig. 1 in the form of a hat-shaped wheel.

Such a heat-dissipating and link-cooling arrangement is described in more detail in Swedish Patent Application No. 0004164-0, filed on November 14, 200, with the title "Heat-Dissipating Arrangement", wherewith the contents of said application shall be considered as forming part of the present application so as to make more apparent an appropriate use application of the present invention in a production line that includes mutually sequential working stations.

Thus, the chain 2 consisting of a series of closed links 21 , 22, 23 shall be adapted for transportation in an arc along the surface section 3b of the rotatable disc 3.

A chain-deflecting roller 4 is adapted to move the chain 2 and its chain sections from the upper planar surface 3' of the disc radially outwards from said disc in an arcuate path, and out over the rounded edge 3c of the disc 3. There is appropriated in this regard that the rotational movement of the deflecting roller 4 should be about its centre axis 4c, in the direction or the arrow. This arrangement also includes an abrasive disc 6, which functions to abrade any slag products that may have fastened to the planar surface 3^' of the disc. In the illustrated case, the chain 2 includes a section 2a, which leaves the link-cooling arrangement 32 and which has a section 2c that shall be curved around the deflecting roller 4, and also a section 2c, which, as a result of its intrinsic weight, presses the section 2c against the peripheral surface 4a of said roller 4. Deflection 2c of the closed-link chain 2 around the deflecting roller 4 with pertinent devices forms a working station for removing slag products that have adhered to the links in the welding station 31.

This arrangement is illustrated and described in more detail in Swedish Patent Application No. 0003879-4, filed on October 25, 2000, wherewith the contents of said application shall be considered as forming part of the present applica- tion so as to make an appropriate use application of the present invention more apparent.

The application was filed with the title "An Arrangement for Removing Slag Products". Figs. 2-8 thus describe and illustrate more clearly a link-welding arrangement 31 that can be used in the production line shown in fig. 1 and having the working stations (3a, 31 , 32', 32 and 4).

The link-welding arrangement 31 has a number of sequentially structured gas flames in the direction of open-link transportation caused by rotation of the disc 3, wherein each of said gas flames functions to deliver an adapted amount of thermal energy to respective links.

The successively generated, and therewith slowly increasing, thermal energy (the temperature) from each of the sequentially structured gas flames shall thus be adapted so as to be able to impart to each of the open links a predetermin- ed or at least a substantially determined rise in temperature during its transportation through the link-welding arrangement.

Thus, in this regard, it is not solely a question of a successively increasing thermal content with equal contributions from respective gas flames, but that there is actually provided a thermal energy edition from respective gas flames that can provide a time-related heating curve favourable to the final welding process.

This provides a more constant temperature, slightly beneath a temperature value applicable to the welding process, immediately prior to the actual welding process.

The gas flame that is situated last in the transport direction, or a group of co-ordinated gas flames situated last in said direction, shall be adapted to deliver to respective links additional heat and to cause an increase in temperature such that in conjunction therewith the welding process will be activated and terminated by causing the weld material and/or flux delivered to the links to melt in the open part of said open links defined by mutually facing end surfaces. These surfaces are situated so close to one another that occurring capillary forces will contribute to the welding or soldering process.

The chosen gas flames shall be mutually co-ordinated to enable the temperature of the chain links to be adjusted at the end of this working station, which temperature may be about 1000°C, to a predetermined link temperature at the end of the link-welding arrangement 31. This temperature is sensed by a temperature sensor 231 and the sensed value is sent to a control unit 200 for appropriate adjustment of the energy supplied to the gas flames or for adjustment of the speed at which the disc 3 rotates. Fig. 2 is a perspective illustration of the external configuration of the working station in the form of a link-welding arrangement 31 , which can be assumed to comprise a casing 31 a, which is fixed relative to a chassis.

A wall-opening 31 b in the casing 31a is adapted to surround respective open links with the smallest possible clearance, as said links 23', 22', 21 ' are fed into the arrangement 31.

It is assumed in this practical application that the link structure will have a more rectangular cross-sectional shape, with one long side lying against the planar surface 3' and the opposite long side facing upwards while the mutually opposite short sides define a right angle with the planar surface 3'. The size of the end-wall inlet opening 31 b can be adjusted with the aid of three motor-driven ports 31 c, 31d, and 31e.

An end-wall outlet opening 31 b' for the casing 31 is adapted to surround the chain 2, consisting of closed links 23, 22, and 21 , with the smallest possible clearance. The sized of the wall opening 31 b' can be adjusted by means of three motor-driven ports 31 c', 31d', and 31e'.

With respect to said thermal energy supply and said temperature adjustment, it lies within the scope of the present invention to create conditions which enable the gas flames to be raised and lowered, as illustrated in more detail in fig. 2.

In this regard, fig. 2 shows that a frame 31f mounted within the casing 31a can be raised and lowered with the aid of screw devices 31 g, 31 h, and 31 i by a driven belt 31 k and by a motor 311 (31 m). The appropriate height of the gas flames is regulated via a control unit 200 in response to the value of the temperature sensed by said temperature sensor 231.

The gas pressure applied to the gas flames shall, at the same time, be adjustable so as to enable the heat supplied and the temperature to be brought to a predetermined value.

Another possibility is to adjust the speed at which the disc 3 is rotated. Fig. 5 illustrates the arrangement with a gas flame, and then particularly the gas flame shown in fig. 3 via the section V-V.

It will be seen that the gas flame 51 has a "core", which terminates at the upper side 52a of the links 21 ', 22', and 23' (52), and that generated exhaust gases are deflected in respective directions under the influence of the upper surface 3' of the disc 3.

In this regard, the arrangement 50 is structured symmetrically about a gas flame centre line 51 ', and consequently only one-half of the arrangement will be de-scribed in greater detail. In the illustrated embodiment, the gas flame 51 is directed perpendicular to the chain links, resting on the upper planar surface 3' of the disc, and are adapted to be deflected symmetrically in respective directions.

A nozzle 53, from which the gas flame 51 issues, is mounted in a casing 54, 54' so that it can be raised and lowered, said casing including cooling chan- nels, which surround the nozzle 53 and form a plurality of exhaust gas channels.

As shown in figs. 5 and 6, mutually opposite wall portions 54, 54' of the casing, enclosing cooling channels 55a, 55b, 55c; 55a', 55b', 55c', with the outermost channels 55a, 55a' being provided with mutually opposing lips 56, 56', are orientated adjacent the disc 3. More specifically, it will be seen from fig. 6 that respective lips 56 shall protrude beyond an extension of the exhaust gas channel 57 among two mutually parallel exhaust gas channels 57, 57a.

Thus, two exhaust channels are situated on a respective side of the nozzle 53, where said two exhaust gas channels are formed by three parallel cooling channels. The cooling channels are formed by pipes, comprised of two parallel sides interconnected by semi-circular end elements.

It is proposed that the length/width ratio shall lie in the range of 10:1 to 40:1 , such as 30:1 , with the exhaust gas channels 57, 57a having generally the same width. Pair-wise connected cooling channels 55a, 55b shall form exhaust gas channels.

The casing wall parts 54, 54' are formed by three or four cooling channels, similar to the cooling channels referenced 55a.

As will be seen from fig. 5, the exhaust gases emanating from the gas flame 51 are conducted via exhaust gas channels, two on respective sides of a nozzle 53, in a direction away from the disc 3, and are deflected through 360 degrees so as to pass through a respective channel 59 and 59a towards the disc 3 on a respective side of a nozzle centre line 51 ', and then again deflected through 360 degrees so as to pass away from the disc 3 through a channel 60, 60' on a respective side of said centre line 51 ', and thereafter led away from the arrangement via an exhaust gas chamber 61.

It will be seen form fig. 5 that waste gas channels 59, 59' close to said centre line are mutually separated by two cooling channels 62, 62a. Referring back to fig. 2, it will be seen that two motors 31 c, 31 d and 31 c',

31d' respectively for actuating side-related ports are co-ordinated to form a support and face towards the centre of the disc.

A third motor 31 e, 31 e' for actuating an overlying port is arranged to extend over the chain. Between 30 and 50 gas flames may be included within the casing 32a.

Oxygen gas is delivered to a channel 53a and acetylene is delivered to a channel 53b.

The sequence of events inside the casing 31 a is monitored by a camera equipment 300, at the position shown in fig. 3. Channels 53c and 53d are intended to conduct cooling water.

The holder 54 can be raised and lowered through the medium of a screw arrangement 53f and an associated nut, which is driven by the wheel 31 h.

Fig. 7 shows that the arrangement is carried by an arm system 70, and that exhaust gases are led to cooling equipment (not shown) via a hose system 71 , 72.

Located downstream of the arrangement 31 is a welded-link displacement device 73 or 32'.

The present invention will now be described in more detail with reference to figs. 9 and 10. The gas pressure regulating arrangement 90, consisting of a practically closed chamber or space 91 , which includes at least one inlet port 91 a for an open-link chain extension, an outlet port 91 b for a chain whose links have been closed with weld material or solder material, and an outlet 91 c for exhaust gases occurring in the chamber 91. Located in the closed chamber 91 is at least one link-welding or link-soldering device 31 , to which a gas or gas mixture, such as acetylene and oxygen, is delivered for welding or soldering purposes, wherein the combustion of said gas or gas mixture is controlled so that combustion will take place under reducing condi- tions, i.e. with an oxygen gas deficiency.

The link-welding or link-soldering arrangement 31 has the form of a tunnel, which is positioned over a supporting structure, which supports the chain extension and the chain.

The surface 56, 56' of the tunnel 31 facing the supporting structure 3' is adapted to define a narrow gap "s" with said supporting structure 3'.

The same applies with respect to a gap allotted to the cooling arrangement 32' and 32 respectively, this gap not being shown in the figures but is nevertheless discernible.

There is applied to the exhaust gases generated in the tunnel 31 a pres- sure (T1 ) which exceeds the pressure (T2) surrounding the tunnel and that prevailing in said chamber, and conditions have been provided for adapted passage of the exhaust gas from the tunnel interior to said chamber 91 .

Connected to the chamber 91 is a fan device or corresponding device 92, which functions to evacuate exhaust gases from the chamber and which is con- trolled to keep the chamber pressure (T2) above the pressure (T3) surrounding said chamber.

Connected to the tunnel is a fan device or corresponding device 93, which functions to evacuate exhaust gases from the tunnel and which is controlled to maintain the tunnel pressure (T1 ) above the chamber pressure (T2). The difference in pressure (T1 - T2) or (T2 - T3) is caused to be less than

10 mm H₂O, through the medium of a differential pressure sensor 94a, 94b.

The pressure difference (T2 - T3) is between 1 and 3 mm H₂O.

The gap "s" is narrower than 0.3 mm.

The gap "s" shall, in principle, be as narrow as possible without danger of sliding contact with the surface 3', it being proposed that the width of the gap is between 0.05 and 0.1 mm.

The speed at which the fan device 92 rotates is regulated in response to a pressure-difference sensor 94b, with higher speeds at higher pressure differences.

The inward port 31 b is adapted to present a narrow opening to outer sur- faces of the open-link chain extension of less than 0.4 mm, such as between 0.1 to 0.2 mm, by adjusting a number of port portions.

The output port 31 b' is adapted to present a narrow opening to outer surfaces of the closed-link chain of less than 0.4 mm, such as between 0.1 to 0.2 mm, by adjusting a number of port portions.

Exhaust gases evacuated from the tunnel 31 are passed through a heat exchange unit 95b for cooling said gases, via a channel 95a.

When leaving the tunnel 31, the temperature of the gases may be in the order of 100-150°C. The gases can be cooled in a controlled manner to a temperature of about

0°C.

The fan device or corresponding device 93 for regulating the pressure in the tunnel 31 is located downstream of the heat exchange unit 95b.

Located downstream of the fan device or corresponding device 93 is a three-way, controllable valve arrangement 96, which functions to regulate the exhaust gas pressure (T4) in the chain and its closed links cooling arrangement 32.

A surplus amount of gas is deflected to the chamber 91 or deflected from the system via the valve arrangement 96 and via a channel 95c, and a part of the surplus is deflected to said chain and its closed-links cooling arrangement 32 via a channel 95d.

The divided part of the gas surplus is subjected to a rise in pressure in a fan device or corresponding device 97, via a channel 95e, and purification in a filter 97a.

The surplus subjected to a rise in pressure is delivered via a channel 95f as a clean-blowing gas stream to said temperature sensor (231 ).

The gas surplus subjected to a rise in pressure is delivered as a clean- blowing and cooling gas stream to a wheel arrangement (32'), adapted for displacing and cooling a closed-link chain.

Said gas surplus subjected to a rise in pressure is delivered as a clean- blowing air stream to a sensor (300) that functions as a flame monitor.

The gas surplus subjected to a rise in pressure may also be delivered as a clean-blowing air stream to a sensor, that includes a mirror, a lens guard or corresponding means.

The clean-blowing air stream is caused to pass one or more constrictions 98a, 98b...98e via the channel 95f.

A part of said surplus is delivered, via a channel 95g, to said chamber 91 , such as via a constriction 98a.

Said divided part of said surplus is caused to be delivered to the chain and its closed link cooling arrangement 32, via a channel 95h, in the event of an overpressure (T4) above the chamber pressure (T2).

The pressure in the arrangement 32 for cooling the chain and its closed links is regulated above a chamber pressure (T2), via said valve arrangement 96.

Alternatively, one or more of said fan devices 92, 93, and 97 may com- prise a device that operates with an ejector effect.

Combustion with an oxygen-gas deficiency is observed by ocular perception of the colour of the flame, such as a yellowish colour, via a channel for the unit 300. Alternatively, the deficiency is determined by combusting evacuated exhaust gases in air, as indicated by reference numeral 99. It will be understood that the invention is not restricted to the afore described and illustrated embodiment thereof and that modifications can be made within the scope of the inventive concept illustrated in the accompanying claims.

Claims

1. A gas pressure regulating arrangement (90) comprising a practically closed chamber or space (91 ), wherein said chamber includes at least one inlet port (91a), for receiving a chain extension consisting of a series of open links, an outlet port (91b), for a chain whose links have been closed by welding or soldering, and an outlet (91c), for the exit of exhaust gases occurring in said chamber, wherein there is located in said closed chamber at least one link-welding or link- soldering device (31), wherein there is supplied to said device the gas or gases required by the welding or soldering process, such as acetylene and oxygen, wherein combustion of said gas or gases is controlled so as to take place under reducing conditions, i.e. with an oxygen-gas deficiency, wherein said link-welding or link-soldering arrangement (31) has the form of a tunnel, positioned over an underlying structure (3), which supports the chain extension and the chain, charac- terized in that the surface of the tunnel (31 ) that faces towards the supporting structure (3') is adapted to define, with said support surface (3'), a narrow gap "s"; in that there is applied to the exhaust gases generated in the tunnel (31) a pressure (T1 ), which exceeds the pressure (T2) surrounding the tunnel (31) and the pressure in the chamber (91 ); and in that there is thereby created conditions for adapted passage of exhaust gas from the tunnel interior (31 ) to said chamber (91 ).

2. An arrangement according to claim 1 , characterized in that there is connected to said chamber a fan device or corresponding device, which functions to evacuate exhaust gases from said chamber and which is controlled to maintain the chamber pressure above the pressure around said chamber.

3. An arrangement according to claim 1 , characterized in that there is connected to the tunnel a fan device or corresponding device, which functions to evacuate exhaust gases from the tunnel and which is controlled to maintain the tunnel pressure above the chamber pressure.

4. An arrangement according to claim 1 , 2 or 3, characterized in that a pressure difference is chosen to be below 10 mm H₂O.

5. An arrangement according to claim 1 , characterized in that a pressure difference is chosen to be between 1 and 3 mm H₂O.

6. An arrangement according to claim 1 , characterized in that the gap has a width or height of less than 0.3 mm.

7. An arrangement according to claim 1 , characterized in that said gap has a width or height of between 0.05 and 0.1 mm.

8. An arrangement according to claim 1 , 2 or 3, characterized in that the speed of said fan device is controlled in response to a pressure difference sensor, with higher speeds at higher pressure differences.

9. An arrangement according to claim 1 , characterized in that said input port is adapted to present to the open-link chain extension a narrow opening, smaller than 0.4 mm, by adjusting a number of port portions.

10. An arrangement according to claim 1 , characterized in that said input port is adapted to present to the open-link chain extension a narrow gap of between 0.1 to 0.2 mm, by regulating a number of port portions.

11. An arrangement according to claim 1 , characterized in that said output port is adapted to present to the closed-link chain a narrow gap smaller than 0.4 mm, by regulating a number of port portions.

12. An arrangement according to claim 1 , characterized in that said output port is adapted to present to the closed-link chain a narrow gap of between 0.1 to 0.2 mm, by regulating a number of port portions.

13. An arrangement according to claim 1 or 3, characterized in that exhaust gases evacuated from the tunnel are passed through a heat exchange unit for cooling purposes.

14. An arrangement according to claim 13, characterized in that the gases are cooled to a low temperature, such as a temperature of about 0°C.

15. An arrangement according to claim 1 , 3 or 13, characterized in that a fan device or corresponding device, which functions to regulate the tunnel pressure, is located downstream of the heat exchange unit.

16. An arrangement according to claim 15, characterized in that a valve arrangement for regulating the exhaust gas pressure in the device for cooling said chain and its closed links is located downstream of said fan device or corresponding device.

17. An arrangement according to claim 2 or 16, characterized in that a part of said surplus is deflected to said chamber via the valve arrangement, and a part of said surplus is deflected to the arrangement for cooling the chain and its closed links.

18. An arrangement according to claim 1 or 17, characterized in that said surplus part is subjected to a rise in pressure in a fan device or corresponding de- vice, and to purification in a filter.

19. An arrangement according to claim 18, characterized in that the surplus subjected to said rise in pressure is delivered to a temperature sensor as a clean- blowing gas stream.

20. An arrangement according to claim 18, characterized in that said surplus subjected to said rise in pressure is delivered to a wheel arrangement adapted for displacing and cooling a closed-link chain, as a clean-blowing and cooling gas stream.

21. An arrangement according to claim 18, characterized in that said surplus subjected to said rise in pressure is delivered to a sensor, functioning as a flame monitor, as a clean-blowing air stream.

22. An arrangement according to claim 18, characterized in that said surplus subjected to said rise in pressure is delivered to a sensor that includes a mirror, a lens guard or corresponding means, as a clean-blowing air stream.

23. An arrangement according to any one of the preceding claims 19 - 22, characterized in that the clean-blowing air stream is caused to pass through a constriction.

24. An arrangement according to claim 18, characterized in that part of said surplus is passed to said chamber, e.g. via a constriction.

25. An arrangement according to claim 17, characterized in that said surplus part is delivered to said arrangement for cooling the chain and its closed links at an overpressure above the chamber pressure.

26. An arrangement according to claim 25, characterized in that the pressure in the arrangement for cooling the chain and its closed links is caused to be higher than the chamber pressure, through the medium of an adjustable valve arrangement.

27. An arrangement according to any one of the preceding claims, characterized in that one or more of said fan devices operates via an ejector effect.

28. An arrangement according to claim 1 , characterized in that combustion with an oxygen-gas deficiency is determined by ocular perception of the colour of the flame, such as a yellowish colour.

29. An arrangement according to claim 1 , characterized in that combustion with an oxygen-gas deficiency is determined by combusting evacuated exhaust gases in air.