JPS5819682A - Pressurized gas sealing method for confining furnace atmosphere and its seal - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Heat treatment tunnels in conveyor tunnel furnaces have long had problems with their end O-seal technology.

41, in the case of furnaces where the combustion chamber or tunnel must be constructed airtight to prevent atmospheric oxidation, to control the partial pressure of (explosive) gases, or to contain toxic gases, seals are required. The issue is important.

In such furnaces, it is necessary in all cases to rapidly cut the atmosphere, but the material to be treated is either continuous, such as strip and/or wire, or in the form of lumps carried on conveyor belts or gutshu boats. Whether it is the product of
Access to and from the furnace room must be provided.

The means of access to and from the furnace chamber should preferably be such that the workpiece can be handled as easily as possible and that gases do not escape across the boundaries of the heating chamber of the furnace.

Previously, it has been proposed that the access to the heating chamber be effected via a mechanical or physical type of seal.

An example of such a sticker is rice 13i4! Huge number,
There are felt pad graphite block seals on each opposite end of the furnace, such as those described in O5, No. 573. For this III#, oil is used as a sealing material.
A non-aqueous fluid seal is also disclosed. Also,
U.S. Patent No. 3. ll, 9. /! ;In the specification No. 7,
A liquid sealing means in the form of opposed water-acting sponge pads is disclosed.

In addition, rice aS 3. ．． 391. , Reissue Patent Specification gλg, No. 141 of the Reissue Patent Specification gλg, No. 141, contains pressure and pressure into the molten zinc bath at the end of the processing area, rather than upper and lower scissor rolls sealing the furnace against the ingress of air. A slidable gate covering the in-wall opening for maintaining the immersion of the wire to be processed is also disclosed.

A single pivot gate as well as a single slidable gate are disclosed in US Pat. No. 9172. No. 42, for example, is known in the art. In this case, a single gate between chambers is automatically activated by a quick switch that engages a tray on the conveyor.

3. Shielding of incident and emitted radiation due to single article drive; /30.2
! ;0 disclosed in the specification.

Pressure-sealed tunnels with multiple article-driven gates or flags to maintain seal pressure below furnace pressure or to retain furnace gas are described in U.S. Pat. No. 2.2g3.3!7. Specification, U.S. Patent No. 3,467
．． No. 366 and U.S. Patent No. 3, 1 Ob, λ11
Issue statement Kl! It is shown.

However, these seals are gas retarders, which are active and highly effective gas retarders to prevent expensive process gases from escaping or air from entering the furnace and causing accidents. It's not a sticker.

For purposes of the present invention, all seals are provided by seal gas. That is, by providing a seal for the pressure chamber by using a pressurized gas seal that does not have a physical structure such as a sponge or a scissor roll for the liquid that needs to come into contact with the material or article to be treated. be.

This objective is accomplished with a pair of seal tunnels, each located at opposite ends of the heat treatment tunnel of the conveyor tunnel furnace. The seal tunnels each extend in a pair of spaced apart transverse directions to provide a seal tunnel having a gas seal opening therebetween. The pair of cross members are formed by spaced apart end walls of the tunnel, each member having a gas seal opening closed by an adjustable sliding gate. Also,
These elements consist of weighted gates pivoted at the open ends of the gas seal tunnels to form at least two gas seal chambers and from the path of articles advanced by one of several conveyor means. It can also be attached to discrete, consecutive pivot points.

Each gate returns to its equilibrium position once the conveyor-carried articles have passed by gravity.

Each gas seal chamber is provided with an inlet gas manifold, or port, connected to a gas source, such as nitrogen, having a set pressure to deliver the required volumetric flow so that the gas seal chamber O gas pressure is slightly below ambient atmospheric pressure. High (and slightly higher than the gas pressure in the heating tunnel of the furnace). This pressure difference accelerates the gas flow through the flow restrictor. No toxic gases will escape from the furnace.

An exhaust gas manifold, or port, is also provided in each gas seal chamber. Connection to a negative pressure source such as ground suction provides another mode of operation. In this case, the pressure in the gas seal chamber is maintained at a pressure slightly lower than the surrounding atmospheric pressure and the gas pressure in the heating tunnel of the furnace. As in the previous case, these pressure differences accelerate the gas flow through the flow restrictor, creating a 'gas quad'.

As shown, a typical conveyor tunnel furnace 20 includes:
Roll 22. Rotatable in four-wheel stand 24.25.
It includes an endless conveyor belt 21 wrapped around 23 rolls, one of the rolls being driven by suitable means (not shown) which are well known in the art. Furnace 2
0 includes an input end RO2B, an output end opening 27, a heating or processing tunnel 28, and a heating or Jl&11 element 2-, all of which are well known in this technical field. The long heating tunnel, ie, the heating chamber, is kept airtight to prevent oxidation of the island covering layer #O.

In addition, this cover! & The wet material has a circular cross section (see Figures 2 and 3).
1a) Wire s1, WR drawing rectangle (Figures 4 and 5)
Kuep or strip material $2, placed on XJt conveyor belt 11 or pusher &-) (Figure 1, No. 4
IQ and Fig. 7) Any of the K-laden lump-like raw materials ss may be used.

The pressurized gas sealing means 34 of II/ is attached to the carry-in end-port 2@, and the pressurized gas sealing means aSS of S is connected to P2・O
It is attached to the discharge end opening 27 of the long heating tunnel 28. These seal means $4, S! ! are the same, so only one of them will be discussed, and each pressurized gas sealing means s4 or ss will be described as follows. A gas cool tunnel S@ through which the l# material can pass, and a pair of spaced apart fluid flow restriction members 37.8@ extending across this gas seal tunnel at all times and forming a gas seal Iis- therebetween. Contains. Each gas seal tunnel 36 has a gas seal end opening 41 at the input end.
and a gas seal end opening 42 at the discharge end.

Each side of the gas seal chamber 3 of each pressurized gas seal of the present invention has an outer am and an inner am. When a pressurized gas seal is used as an inlet seal to the furnace 2, the outer am
is the surrounding atmospheric chamber and the inner chamber is the furnace tunnel 28, which is maintained at positive gas pressure by the first gas pressure supply means 40.

Each gas seal is provided with an inlet gas manifold 43 connected to a second gas pressure supply means 44 which supplies a gas, such as nitrogen, at a set pressure to meet the requirements. A volumetric flow of gas is directed into gas inlet port 45 .

In another mode of operation, each gas school is provided with an exhaust gas manifold 48 connected to a source of negative pressure 470, such as a mill suction, and adapted to exhaust gas seal gas through an exhaust port 48. It is being

3 and 3, the gas sealing chamber 39 is also supplied with a volumetric flow of sealing gas by the supply means 44 via the inflow gas port 4s and the inflow gas manifold 43. The flow of sealing gas creates a positive pressure that is slightly higher than the gas pressure within the furnace 20 and greater than the ambient atmospheric pressure within the outer region 4s of the gas sealing chamber 3.
It is adjusted to hold. I! ! The seal gas used is most often inert. However, in some applications, such as the containment of toxic gases, air can be used, and in other cases it is also possible to use the derived product gas.

According to the elevated temperature operation of the sealing means $4 or 3i,
Performance can be improved by using the expanded seal gas. Operating costs can be lowered by reducing the required mass flow rate of seal gas for any given volumetric flow rate within the gas seal.

#Figure Ia, No. ? The embodiments of FIGS. 1I, 1E, and 5 are designed around the geometry of the wire 31 and web 32. 2 and 3, a continuous wire 31 having a circularly symmetrical cross-section is shown being forced through the furnace 20 for processing in place of the endless conveyor belt 21 shown in FIG.

In this embodiment, a pair of spaced apart, transversely extending flow restriction means 37, 3B are provided at the end wall 5 of the tunnel 36.
1.52, each having a sealed end opening 53.54 therein and a pair of adjustable gates 5156 each mounted for sliding across one of the openings 53.54. have. Each gate 55 or 56 includes a notch 5T or s8 in the lower edge 59;
Each opening has a complementary notch 61 or 62 in the upper edge 63.
which together surround the advancing wire and seal the openings 53, s4 against gas leakage. Each notch has a circular cross-section. The notch can be tightly moated around a wire of uniform circular cross-section, or if wires of different diameters are to be processed, the notch can be formed at a suitable angle, as shown. It is possible to form a polygonal aperture with a desired cross-sectional area by holding it to avoid excessive leakage.
S! ! S 511 is preferably slidably adjustable by a common central rod 64 from outside the tunnel s6 so that the gate can be raised or lowered to adjust the seal end opening 11 to the required clearance. When the flow area decreases in this way, the sealing gas flows to the sealing gate ss%
The vehicle will accelerate at high speed at S6. Such a fast flow helps prevent back-diffusion contamination of the process atmosphere. Adjustable goo)! ! ! . If the seal chamber pressure is adjusted to be higher than the atmospheric pressure at 49 0 j The Kf and 6' gases are set to 1 so that they do not mix.

In Figure Ha and Figure 5, the material being handled is a web or strip 32 and a slidable adjustable gate 55
．． A pair of slidable and adjustable gooses similar to 5) Is,
iii is the tunnel m wall ss.

71 and thereby define spaced apart transversely extending flow restriction members 37, 38.

The lower edges T2, T3 of the gate 65, SS are flat and in the same plane, and the gas seal opening 67. @8 upper edge 14,
Since T5 is also flat and in the same plane, a rectangular opening is formed that fits closely with the rectangular cross-section of the web or strip 32. Each gate ss, Is has, instead of a common control rod li4, an individual control rod 76 or 11, which makes it possible to obtain the desired clearance.

The discharge waste manifold 46 includes means for removing foreign matter that diffuses back into the sealing chamber. By applying suction to these manifolds, all foreign matter can be swept away from the seal fabric.

These inlet/outlet gas seal chambers 4 also provide the operating mode of the seal O#I. By closing the inlet gas manifold 43t and applying a large suction force to the exhaust gas manifold 41, the previously defined gas flow pattern is reversed. The high-speed flow of gas in the inner and outer chambers seals iiSIKM! It flows into the discharge Maejo No. 41. By balancing the inner/outer volume R1 and providing sufficient suction power, cross-contamination can be completely avoided. When operating in this mode, the previous cost of introducing seal gas is WIIK.
*can. The sealing action works on the gas in the inner/outer chambers, since the major function of a gas seal is the flow capability.Of course, in the case of toxic or flammable process gases, these gases are It is necessary to combust the gas appropriately.

Strips and wires have fixed geometries and dimensions. In this case, if there is a desire to reduce the flow area around the part undergoing treatment, this can be easily achieved. However, sintered parts 1 brazed aircraft parts,
For bulk products such as printed circuit boards and steel heat treated mechanical parts, mating openings are not always possible. Figure 81, JI6 and Figure 7 are
A series weighted gate pressure seal is shown.

The seal has a normally rectangular tunnel opening through which the bulk product can pass. A minimum of one chamber in series is required. This corresponds to three weighted gates. The number of chambers in series is not counted with the overall pressure difference increasing with the number of individual chambers.

In this embodiment, spaced apart, transversely extending displacement control members sr, sa are provided with three weighted gates 78, ?, each with a gas seal chamber s1 or 83 between them. ! 1
and 82 are formed by two. Since the gates are separated from each other, the two gates always hang downwardly from their respective pivot points 84, 85 and 86 due to gravity. When the product is placed on the conveyor and ascends to the ζ grooves 71 at an angle 91, the remaining gate forms a gas seal chamber.

Each mat and $3 of pressurized series gas seal II
It operates in the same way as the seal shown in Figures 2-5.

Each chamber is provided with an inflow gas manifold 43 and an exhaust gas manifold 4@. Each chamber has a pair of inflow/output gates -71 and 1, or T and 2, these gates are pivoted on low friction bins at pivot points $4.8S or $6. There is. Since these gates are weighted -2, the pressure difference between the two rising contacts only results in a small balanced gate pivot angle. Weight 92 determines the pressure rating of chamber s1, $s. Gate dimensions are tailored to the tunnel shape to reduce flow area. The bottom flow area based on the equilibrium gate pivot angle [1] determines the required volumetric flow rate corresponding to the required chamber pressure.

The side and top crossing areas are independent of the pivot angle.

As discussed above, reducing the flow area increases the top/bottom toR speed of the gate and helps reduce process gas backdiffusion. The weights 92 necessary to maintain a balanced gate pivot angle are stubs. As the equilibrium gate pivot angle IIO increases, the chamber pressure decreases rapidly for a constant volumetric flow rate. In a series arrangement of chambers, each gate is successively weighted at increasingly higher points, as indicated by sl, so that the chamber pressure increases progressively.

When each chamber is operating at its equilibrium pivot angle [-O, the operating wall of the seal is the same as discussed for the strip and wire seals. However, when the bulk product or wire basket is forced through the seal by the conveyor mechanism 21, the gate has to open to a very large pivot angle fK, as indicated by sl. (Note that the gate will be opened by the product being transported on the conveyor. If the material being conveyed by the conveyor is too fragile or shallow to lift the gate, it may be necessary to place the material in a heavy wire basket.) ) If the pivot angle becomes very large,
Gates are useless; in fact, one adjacent wealth acts as one large chamber. Importantly, the space of the Kotsubair transport product is greater than the two sealing chamber lengths, so that in any one II only one gate is lifted at a time.

If product space is not taken into consideration, all gates may open at the same time, leading to direct mixing of the atmosphere in the inner/outer chambers. Since only one gate is open at a time, the A-chamber, 3-gate pressure seal is the smallest in size. When one gate closes, the remaining two gates determine the pressure chamber. In other implementation M, 4! r1i
! The inlet and outlet gas manifolds are provided. The vacuum 1 pull in the exhaust manifold removes any foreign matter introduced when the gate is opened to the atmosphere in the inner/outer chamber. For strip or wire cooling, the series weighted gate pressure seals of FIGS. 1, 6, and 7 can also operate under suction mode.

In some conveyor-type furnaces, slow belt speeds are common because long processing times are required to cover short distances. At low belt speeds, requiring the bulk product space to be larger than the length of one sealing chamber does not increase efficiency and increases costs; the hot area of the furnace is only partially used. If the hermetic backing reaches its thermal load limit, the problem becomes somewhat less severe.

If a tight backing is required, the loaded and unloaded tables of the furnace are run at a linear speed that is greater than the linear speed of processing by the ratio of product space to product length.

In the method of the present invention, the first and first pressurized gas seals provided at both ends of the elongated heat treatment furnace subjected to gas pressure are each provided with a gas seal having at least one gas seal chamber therebetween. either by one slidable gate or by three pivoted gates forming at least 1000 gas seal chambers between them. When supplied and maintained at a pressure higher than the gas pressure in the processing tunnel and higher than the surrounding atmospheric pressure, a gas lock is formed which prevents leakage of gas into the processing tunnel or from the sensitive tunnel. Ru.

Establishing and maintaining a set pressure within each gas seal chamber includes delivering a sufficient volumetric flow to the gas seal chamber, while at each opposite end of each gas seal chamber or tunnel, the pressure is higher than the gas pressure within the furnace; This is accomplished by maintaining a flow restriction that is above the surrounding atmospheric pressure. The slidable gate is adjusted to the gap and the pivotable gate is adjusted to the weight so that the difference between ambient pressure, gas seal chamber pressure and furnace pressure is passed through the flow restrictor formed by the gate. , and causes an acceleration in the flow at that point, preventing mixing or diffusion of gases.

The invention is not limited to the application and detailed construction described and illustrated herein.

The present invention can also be used in devices other than furnaces.

Applications such as chilled jaconveyor paint spraying are examples of other applications of the present invention. It should be specifically noted that these seals can be used between various furnace chambers and/or regions.

[Brief explanation of drawings]

Figure 87 is a side view of a typical conveyor tunnel furnace equipped with pressurized gas seals of the present invention at the input and output ends. FIG. 2 is a partially enlarged side view in half section of an embodiment of the pressurized gas seal of the present invention using wire material. FIG. 3 is a front view of the seal of FIG. 2; FIG. 4 is a view similar to FIG. 1 of a pressurized gas seal of the present invention using web or strip material; Figure #Is is a front view of the seal of Figure 1. FIG. 6 is a view similar to FIGS. 2 and g+ of a pressurized gas seal of the present invention using bulk products on a conveyor belt. FIG. 7 is a front view of the seal of FIG. t46. 20...furnace 28...heating tunnel 34.35...pressurized gas sealing means 36...gas seal tunnel 39...gas seal chamber 55.56...engraving of gate drawing (contents, 2 No change) Figure 1 Procedural Amendment (
Method) 1. Indication of the case 1981 Patent Application No. 11137
0 No. 2, Title of the invention Pressurized seal method for sealing the furnace atmosphere and the seal 3. Relationship with the case of the person making the amendment Applicant 4, Attorney 5, Date of amendment order Voluntary 6, Amendment Subject to application form, all drawings

Claims (1)

[Scope of Claims] 1. At each diagonal end of the tunnel, each gas seal is formed by at least λ spaced apart flow restriction gates and arranged to define at least one gas seal chamber between the gates. By providing the thermal J6i
l) A method of sealing the pressure gas in the tunnel against the ingress of air into the tunnel and the leakage of gas from the tunnel, the gas pressure being higher than the gas pressure in the heat treatment tunnel and surrounding atmosphere. establishing and maintaining a constant volume flow of OV-ru gas into the Renki gas chamber at a pressure higher than the pressure; and articulating the gate to reduce the pressure difference between the atmospheric pressure and the seal and inside the tunnel. A method of sealing pressurized gas in a thermal tunnel, consisting of a step of restricting the flow rate, accelerating the flow rate and preventing gas mixing or diffusion. Yu said gate t! 2. The method of claim 1, wherein the step of -1l'lIJ is performed by sliding the gate from outside the gas seal. 3. The method of claim 1, wherein the step of articulating the gate is performed by pivoting the gate to a closed position under a selected weight or gravitational influence. Gas for the entrance or exit of the hot section 1 tunnel, which is of a type having at least one flow rate restriction gate arranged at a distance from each other and forming at least one gas seal chamber therebetween, and which operates at a predetermined gas pressure. in the seal, means for establishing and maintaining a set volumetric flow of sealing gas into the gas seal chamber at a pressure higher than the gas pressure in the heat treatment tunnel (and higher than the surrounding atmospheric pressure); and a gap opening in the gate; by adjusting the tunnel,
and means for accelerating the gas flow through the gate opening by means of a pressure difference between the gate opening and the atmosphere to establish a gas lock in the right circle. 3. The flow rate limiting gate is installed to slide to open and close, and the means for adjusting the opening between the gates is at least seven control rods connected together. 5. The gas seal of claim 4, wherein the control rod extends outside the gas seal and is adjustable during operation from outside the gas seal. 6. The flow rate restriction gate is pivotally mounted so as to be opened and closed individually and continuously by the drive of the article passing through the gas seal, and there are 88 gates between the pivotally mounted gates. The means for adjusting the at least three said gates forming at least one of said gates is selected to return each gate to an equilibrium position due to gravity and the gas pressure within the meter once each article has passed said gate. and a weight on said gate that is
Gas seal mentioned in the reference section.