JPS5948887B2 - fitting device - Google Patents

Description

[Detailed description of the invention] TECHNICAL FIELD The present invention relates to pipe fittings that utilize memory metals.

Thermorecoverable articles, i.e. articles that have been transformed from an initial thermally stable form to a second thermally unstable form and that can be returned or recovered towards said initial form by applying heat alone. It has many uses in various fields.

Such articles are typically made from polymeric materials, particularly crosslinked polymers, and are described, for example, in U.S. Pat.
No. 62 (Currie) and No. 3.086.242 (
Cook et al.).

Recently, it has been discovered that such articles can be made from a class of metals often referred to as "memory metals" or "memory alloys."

These metals exhibit changes in strength and morphological properties when passed through a transition temperature, often between the martensitic and austenitic states.

Articles made from these metals can also be used to make heat recoverable articles by deforming them while in the martensitic and cold state.

The deformed form of the article is maintained until it is warmed above the transition temperature to become austenitic and recover to its original form.

The deformation used to place the material into a thermolabile form is usually referred to as thermorecoverable plastic deformation and can be imparted by introducing strain into the article above the transition temperature, The article then assumes a deformed form upon cooling through the transition temperature.

It is understood that the transition temperature may be a temperature range, and that hysteresis usually occurs so that the exact temperature at which the transition occurs depends on whether the temperature is rising or falling.

Furthermore, the transition temperature is a function of variables such as the strain force applied to the material, the temperature increasing as the strain force increases, and so on.

Among these memory metals, notable ones include, for example, U.S. Pat.
．． No. 463, No. 3.753.700, No. 3.759.55
2, British Patent Nos. 1.327.441 and 1.327
．． 442 specifications and NASA issue 5P5110
There are various alloys of titanium and nickel described in ``55-Nitinol-Memory Alloy, etc.'' (U.S. Government Printing Office, Washington, D.C., 1972), the contents of which are not included herein. shall be referred to.

However, heat recoverable properties are not limited to such titanium-nickel alloys.

Thus, for example, various beta brass alloys exhibit this property.

For example, 5cripta by N. Nakanski et al.
Metalurgica5.

Pages 433-440 (Pergamon (Pres.
s1971).

) Such materials can be doped by known techniques to lower their transition temperature to low temperature systems.

Similarly, E. Enami et al., supra, 663
~Page 68 shows 3 as having such properties.
04 stainless steel is shown.

The contents of these descriptions are also referred to in this specification.

British patent specifications 1.327.441 and 1°327
, 442, utilize this thermally recoverable property as a unitary structure contractible member (i.e., thermally recoverable) useful for joining cylindrical substrates such as spaceflight hydraulics and other conduit systems. describes how it can be used to fabricate tubular articles (tubular articles in which forces are directed radially inward).

In the fabrication of such heat-recoverable fittings, the fittings are cooled below their transition temperature, for example by immersion in liquid nitrogen, and dimensioned to be larger than the original internal diameter of the fitting. The joint is expanded diametrically by pressing an outwardly tapered mandrel against the joint.

In this type of unitary thermally recoverable metal joint, the inner surface of the joint is machined prior to diametrical expansion so that the joint later heats around the substrate and "cuts into" the surface of the substrate. ” or otherwise provided with teeth that deform its surface.

This increases the resistance of the resulting article to tensile stresses and, in special cases, achieves an airtightness of the interface between the joint and the base body (as used herein "airtightness").
The term 211 kg/cm2 (3000 ps
ig) refers to the ability of a pressurized article to not pass more than 1 bubble per minute for 5 minutes when immersed in water).

A number of problems arise from providing such teeth on the inner surface of a unitary heat recoverable metal joint.

First of all, this tooth is subjected to great local pressure during expansion on the mandrel, as a result of which the tooth often suffers from defects that give rise to the following conditions:

That is, (a) impairing the ability of the joint to form an airtight joint;

(b) Reducing the tensile strength of the joint.

(c) To lower the amount of pressure that the joint can resist.

Second, many metal materials that are susceptible to heat recovery are difficult to machine.

Other problems arise from the unitary construction of previously used joints.

For one thing, such fittings recover too quickly when placed on a warm substrate, in which case special measures are required to prevent recovery from occurring before the fitting is in its correct position on the substrate. It is necessary to use cooling equipment.

Furthermore, strict quality control is required to ensure that all lubricant deposited on the inner surfaces of the fitting used to aid in expansion by the mandrel is removed prior to its use.

Finally, by somewhat limiting the range of materials that are susceptible to heat recovery, an optimal combination between the joint and the base material from mechanical, chemical and electrical points of view may be hindered. There is.

For example, this may be hindered from the viewpoints of corrosion resistance, thermal expansion properties, creep resistance, sealing properties, elastic modulus compatibility, high temperature strength, and the like.

The present invention comprises a thermally expandable member made of a memory metal and a sleeve member located outside the thermally expandable member, the sleeve member being such that the material provides a secure joint between the device and the substrate. A pipe fitting device is provided having a configuration and/or made of materials that facilitate the formation of a pipe fitting.

The present invention also provides a set of parts for making the above-described device consisting of a sleeve member suitable for being placed outside a thermally expandable memory metal member made of memory metal.

The pipe fitting device of the present invention can be used not only for connecting pipes, but also for repairing damaged pipes, such as plugging holes in or connecting broken pipes.

As used herein, the term "tubular" is not strictly limited to cylindrical hollow members, but rather irregular and/or hollow members.
It also includes members having various cross-sections, as well as members having, for example, Y-shaped, T-shaped, and X-shaped cross-sections.

Since the heat recoverable member of the present invention does not need to have teeth, the method of deforming it is simple.

In devices useful in accordance with the invention, the memory metal member is, for example, a short thermally expandable rod or tube, in which case the sleeve member is preferably positioned snugly around the memory metal member.

Such devices are used, for example, to connect pipelines internally.

Although the sleeve member may be formed as a single piece, such as a tube, the invention is not limited to such a shape, for example a segmented cylinder (the term "cylinder" is used in the general It would be advantageous if other shapes could also be used, such as those used in sense and not limited to a perfectly circular cross section.

As discussed herein below, it will be appreciated that all that is required is for the sleeve member to cover at least a substantial portion of the surface of the memory metal member, if the memory metal member does not. Otherwise, it will come into direct contact with the substrate during the joint.

Preferably, the sleeve member is sized and shaped such that upon recovery of the heat recoverable member, at least one of the dimensions of the sleeve member changes and the change in dimension engages the substrate.

In one preferred embodiment of the invention, the sleeve member has at least a portion of its major surface adapted to create a firm and preferably gas-tight seal between the device and the substrate upon retrieval of the device. Means are provided.

Such means preferably consist of at least one tooth on the main surface of the sleeve member.

Referring to the preferred tubular form of the device, the teeth are preferably arranged radially and more preferably circumferentially about the longitudinal axis of the sleeve member.

Advantageously, the sleeve member is provided with a plurality of teeth on each side of its midpoint.

However, other means may also be used to provide a good seal, for example ``the sleeve member may be provided with a ring of deformable material such as annealed aluminum or copper; It may also be coated with, for example, fluorocarbon or other polymeric materials or plated with easily deformable metal.

The sleeve member is advantageously provided on each of its major surfaces with means for establishing good contact between itself and the heat-recoverable metal member and between the coupling device and the base body. for example, each of its major surfaces may be provided with one or more teeth, and preferably each is provided with a plurality of teeth on each side of its midpoint. It will be done.

Advantageously, such teeth may be arranged in pairs, one formed on the outside of the sleeve member and the other formed on the inside of the sleeve.

Of course, the number, shape and location of the teeth will vary according to the material from which the teeth and the substrate are made and the type of interlock desired therebetween.

In another preferred embodiment of the invention, the sleeve member has at least one weakened wall section, preferably at least a pair of weakened wall sections.

For example, the weakened areas may be pores opened in the wall, or they may be "thin flat areas", i.e. the thickness of the wall is partially reduced, preferably these pores and the thin flat portions are arranged parallel to the axis of the sleeve member and the pairs of pores or thin flat portions are preferably arranged symmetrically such that a relatively uniform deformation of the sleeve member in its circumferential direction occurs upon recovery. Placed.

Preferably the pores and thin flat portions are equidistant from the end of the sleeve member and at least two pairs of pores or thin flat portions are provided on each side of the unweakened midpoint and equidistant from the midpoint. It is advantageous to be prepared.

Preferably, the thin flat portion is formed on the outer surface of the sleeve member.

Another preferred form of the weakened sleeve member has all its outer surfaces tapering from a maximum wall thickness at points adjacent its ends to a minimum wall thickness at a narrow midsection; Preferably, the inner surface of the sleeve member is uniform.

In all of the above cases it is preferred that the sleeve member is provided with a plurality of said teeth on its surface, preferably on either side of its midpoint.

Alternatively or additionally, it may also be preferred to construct the sleeve member from a material that is susceptible to abrasion, as discussed below.

In another preferred embodiment of the invention, the sleeve is made of abrasive material, such as metal.

"Abrasion" refers to a condition that arises from the affinity between metals that are easily abraded. Seizure occurs, followed by cracking and fracturing, resulting in an increase in surface roughness.

American Society for Metal
s, 8th edition ('1961), Metals Handbook 1st
See Volume 18.

(As used herein, the term "metal" means both pure metals and alloyed metals unless otherwise specified).

Abrasive metals may abrade each other and other metals that are similar in hardness, surface properties, and chemistry.

Particular frangible metals include titanium, aluminum, magnesium, and zirconium, and the sleeve member of the present invention can be made from such metals.

A preferred sleeve member is made from commercially pure titanium, such as titanium 50A.

One suitable titanium alloy is designated Ti-3A I-2,5V and is a titanium-aluminum-vanadium alloy.

The preferred aluminum sleeve member is made from 6061 aluminum series, preferably 6061T6 aluminum.

Their alloys are approximately 1% magnesium, 0.6% silicon, 0
．． Consisting of 25% copper and 0.25% chromium, and the balance aluminum.

Other suitable materials for the sleeve member include commercially pure zirconium, Zircaloy 2 (approximately 1.5% soot,
0.12% iron, 0.1% chromium, 0.005% nickel, and balance zirconium) manufactured by Zirconium Tec of Albany, Oregon.
It is an alloy obtained from H. Corp.

Also mentioned are magnesium alloys obtained from, for example, Dow Chemical Corp., which are
231B-F (approximately 2.5-3.5% aluminum, 0
．． 7-1.3% zinc, minimum 0.2% manganese, and balance magnesium) and ZK60A-T5 (contains approximately 4.8-6.2% zinc, 0.45% zirconium, and balance magnesium) ) is named.

For example, the sleeve member may be a simple tubular sleeve formed from abrasive metal, and the sleeve member may be a simple tubular sleeve formed from abrasive metal, and either between the sleeve member and the heat recoverable member or between the sleeve member and the substrate. There is also no need to provide other means to ensure a good seal.

Other means may be provided on the sleeve member (as described above) to provide a good seal, provided that such means are provided on only one of the major surfaces of the sleeve member. It is also often advantageous to make the sleeve member from a material that is susceptible to abrasion.

Briefly, if the contact surfaces, whether at the interface between the sleeve member and the heat recoverable member or the interface between the sleeve member and the substrate, are both substantially uniform;
It is advantageous for the sleeve member to be made from a material that is susceptible to abrasion.

To obtain the maximum benefit offered by the use of abrasive materials, the surface roughness of the sleeve member should be equal to or greater than the roughness of one of the surfaces it contacts in any particular application. It is desirable that the roughness is similar to that of the roughness.

For example, for the hydraulic conduit system in which the device is used, the generally uniform surface of the sleeve member is approximately 3.
．． It will advantageously exhibit a profilometer roughness of 18 microns (approximately 125 microinches) or less, more preferably 1.6 microns (63 microinches) or less.

As will be appreciated from the foregoing discussion, the dimensions, configuration, and materials of the sleeve member should be selected to ensure effective operation, taking into account the characteristics of the heat-recoverable metal member, the substrate, and the environment in which the device of the present invention is to be used. selected as obtained.

Thus, while the above discussion is directed to providing teeth on the sleeve member, providing a weakened portion in the insert sleeve member, and forming the sleeve member from abrasion-prone materials, respectively; A given sleeve member can combine any two or all three of these requirements, and in fact in any application its operation can be modified to include alternative designs and/or materials. It would also be obvious to do so.

For example, the sleeve member may be provided with a coating of polymeric material or deformable metal, as described above, to facilitate the formation of an airtight seal, eg, upon recovery.

Furthermore, the insert may be provided with teeth and/or weakened portions only in parts of its structure.

In some embodiments of the invention, the sleeve member is itself provided with an insert or an external auxiliary member to facilitate the overall action.

Special cases where this is advantageous are when the compatibility requirements between the sleeve member and the heat-recoverable metal member differ from those between the sleeve member and the base body, or for example between two hydraulic pipe bases. As in the case of forming a fluid-tight joint, each part of the sleeve member serves two different functions, such as proper mechanical coupling in pipes and pipe-to-pipe functions. This is the case when the function of forming a corrosion-resistant seal is required.

It is also suitable to provide one or more toothed members spaced apart from the midpoint on a sleeve member having a generally smooth corrosion-resistant surface.

Similarly, it is also possible to provide a sleeve member having general compatibility with the heat-recoverable metal member for the purpose of corrosion-resistant sealing and providing a suitable mechanical connection with its substrate. It has been found to be advantageous in some cases.

It will be appreciated that those concepts also apply to the outer sleeve member and also to compatibility with and satisfactory mechanical coupling to the heat recoverable metal member.

The sleeve member may be provided with a groove or other recess or otherwise shaped portion for proper positioning of another auxiliary insertion (external) member.

Additionally, the sleeve member and/or the auxiliary insert member may be resilient to facilitate secure positioning.

If the sleeve member is to be provided with such a separate auxiliary insert member, it may be provided with apertures or formed into an elongated segmented sleeve member to accommodate the separate auxiliary insert member. It is advantageous to pass or be able to be inserted through said pores so as to place the pores in a defined position.

However, this is not essential in all cases; it would also be possible, for example, to push the auxiliary insert member in from one end of the sleeve member.

Although the present invention is particularly directed to avoiding the disadvantages that arise when heat-recoverable metal parts are provided with teeth, problems that sometimes arise with the provision of teeth, such as difficulties in machining. However, deformations, such as deformations of the teeth that occur during expansion by the mandrel, are not always significant.

For example, some heat recoverable alloys are relatively easy to machine, and in certain applications some tooth deformation during deformation operations may not be significant.

Furthermore, it may be even more advantageous when providing teeth in this manner.

The invention therefore also encompasses devices in which the thermally recoverable member is provided with means, for example provided with teeth on one or more of its major surfaces. It is clear that the present invention is not limited to smooth-surfaced recoverable thermally expandable members.

In preferred tubular devices of the invention, the length of the sleeve member may be greater than, equal to, or less than the length of the heat recoverable, eg, heat expandable, member.

Preferably, however, the sleeve member projects from each end of the heat recoverable member so as to provide strain relief adjacent the opposite end of the recovered member.

In such cases, the length of the sleeve member is preferably no greater than about L+2 De, where De is the outer diameter of the thermally expandable member, and more preferably no greater than about 10 De. do not have.

Preferably, the sleeve member of the device is metallic.

However, other materials with metal-like properties but strictly non-metallic, such as graphite, graphite-glass composites, etc., could also be used in various applications.

Suitable materials are known and their selection will be readily available to those skilled in the art.

In the preferred use of the composite device of the invention for joining adjacent lengths of hydraulic tubes or other tubes made, for example, of stainless steel, titanium or aluminium, the sleeve is made of a metal having a predominant proportion of titanium. Preferably, it is made of.

The base of the titanium sleeve member is stainless steel.
For example, it is particularly preferred if it is made of 21-6-9 stainless steel (21% chromium, 6% nickel, 9% manganese).

If the substrate is made of a highly abrasive metal, the sleeve member can be made of a less abrasive metal that will abrade if it is brought into contact with the substrate.

For example, if the substrate is titanium, the sleeve member may be stainless steel.

These sleeve members are non-resilient.

Preferred metals for use in heat recoverable components include equiatomic titanium-nickel alloys and, in particular, substituted ternary alloys as described in U.S. Pat. Included.

Selection of suitable dimensions for a coupling device according to the invention will be easy for those skilled in the art.

It is recognized that the present invention substantially overcomes all the disadvantages of heat recoverable metal joints previously used.

By inserting the sleeve member between the heat recoverable member and the substrate around which the member is ultimately recovered, contamination of the substrate with various residues is prevented;
and the combination of the sleeve member and the substrate material for compatibility from mechanical, chemical and electrical points of view, i.e. corrosion, thermal expansion, creep resistance, sealing properties, elastic modulus, flexibility and high temperature strength. can be determined.

Any teeth provided in the coupling device can be formed on the sleeve member so that they are not exposed to the destructive forces introduced during expansion with a mandrel.

Since the heat-recoverable member does not need to have teeth, the manner in which it is expanded is simplified, eg bead or ball expansion can be carried out in addition to mandrel expansion.

A thermally recoverable element, also referred to as a "driver", which upon its recovery drives other elements of the composite device towards recovery, can be located within the other elements mentioned above; The other members mentioned above are thus forced outward rather than inward.

In such cases, the driving body may be solid or hollow.

Similarly, while the use of teeth is particularly advantageous in many coupling devices according to the present invention, the ability of the seam formed to resist tensile stresses by constructing the sleeve member from abrasive materials is significantly enhanced. It must be emphasized that

In fact, in certain cases, the resistance to tensile stresses is better when a frangible sleeve member with a uniform surface is used, which may dig into the substrate or otherwise deform it. It was discovered that this is larger than when multiple circumferential teeth are provided.

Next, the present invention will be explained in detail with reference to the accompanying drawings.

Figures 1a and 1b show a composite joint formed in accordance with the present invention, where the heat recoverable member or driver is located within the other member.

In FIG. 1a, the edge-aligned substrate is the heat recoverable member 7.
0. The tubular member 69 is located around the tubular member 69.

Of the two major surfaces of tubular member 69, the outer surface is generally straight, and the inner surface is uniform with maximum wall thickness at or near the ends and minimum wall thickness near midpoint 71. It has a sharp taper.

Thermal recovery of member 70 causes deformation of the sleeve member and substrate as shown in FIG. 1b, increasing the resistance of the resulting joint to tensile stress.

This type of joint device is particularly useful when connecting substrates where external joints cannot be used because of the space required around the joint.

Heat recoverable member 70 is shown as a solid rod.

However, if it is necessary to provide a fluid passageway, a tubular driver can be used.

Inserts of the invention with weakened wall sections can also be obtained by forming one or more pores or elongated thin flat sections in the insert.

The thin flat portions are regions of the outer surface of the insert where the wall thickness is locally reduced.

Preferably, the pores and the thin flat portion are arranged parallel to the longitudinal axis of the insert.

Typically, at least one pair of pores or thin flat sections are used in an array so that the deformation of the insert around the circumference is relatively uniform, for example due to a symmetrical arrangement.

Referring to FIG. 2, a perspective view of a tubular sleeve member 72 for a composite joint formed in accordance with the present invention is shown.

Sleeve member 72 has a weakened wall portion defined by a pair of pores 73 whose long dimension is parallel to the longitudinal axis of the insert member.

The midpoint of the pore corresponds to the midpoint of the sleeve member, and its ends are equidistant from the ends of the sleeve member.

FIG. 3 is a perspective view of a tubular sleeve member 74 similar to FIG.

However, in sleeve member 74, the weakened wall portion is formed by a pair of elongated thin flattened portions 75 parallel to the longitudinal axis of the sleeve member.

FIG. 4 is a perspective view of another tubular sleeve member 78 useful in the composite joint of the present invention.

Sleeve member 78 has a weakened wall portion formed by two pairs of apertures 79 located on either side of an unweakened intermediate section 80 .

The sleeve member 81 of FIG. 5 is the same as that of FIG. 4, except that the weakened wall portion is comprised of two elongated thin flat portions 82 disposed around an unweakened intermediate portion 83.
They are two pairs.

Although the major surfaces of the sleeves of FIGS. 2-5 are shown as generally straight, either or both surfaces may be provided with teeth as described below.

Preferably, a plurality of teeth are provided on both sides of the intermediate portion of the sleeve member.

The use of teeth further improves the tensile stress resistance of the recovery joint.

Alternatively, or in addition, the sleeve member can be made from abrasive materials as described above.

It will be apparent to those skilled in the art that the degree to which the sleeve member is weakened will determine the extent to which it deforms as it is compressed due to thermal recovery of the compressed sleeve.

In the case of pores, the degree of weakening is determined by the number, length and width of the pores.

In the case of thin flats, the number, length and width of the thin flats as well as their depth determine the degree of weakening.

For example, a resilient driver can be positioned inside another member such that expansion and recovery of the driver forces the other member more outwardly than inwardly.

In such a case, the driving body may be a tubular sleeve member or may be solid.

The expandable and recoverable drive body is conveniently obtained by drawing a solid or hollow rod of the desired heat-stable diameter to the desired heat-recoverable diameter while retaining the martensitic state by methods well known in the art. .

When heated to temperatures that exist in the austenitic state, the rod expands in diameter and contracts in length.

FIG. 7 shows an alternative form of sleeve member 111 with four large longitudinal pores 112 so that the sleeve member actually forms a cage.

The purpose of this basket is to house auxiliary inserts.

For example, the sleeve member 111 can be made from a soft metal that is compatible with hydraulic fluids and has good contact with heat recoverable metal drives.

In this case, it is advantageous to insert a further auxiliary member 113 as shown in FIG.

The auxiliary member 113 is provided with outer teeth 114 to facilitate positive contact with the sleeve member 111 and a central annular ear 115 that can cooperate with the groove 116 of the sleeve member 111 to facilitate correct positioning. will be provided.

Of course, the auxiliary member 113 can also be provided with internal teeth for contacting the base body.

Preferably, portion 115 is flexible so as to exert positive positioning pressure on 116.

Alternatively, in other applications it may be advantageous for the sleeve member 111 itself to be toothed (or machined to facilitate wear) and to be flexible, in which case a central soft sealing ring such as ring 109 in FIG. It can be located in the groove 116 and held there by a spring force on the part of the sleeve member 111.

Although certain sleeve members and auxiliary members have been described, it will be appreciated from the foregoing description that many other variations are possible depending on the particular application desired.

[Brief explanation of the drawing]

1a and 1b are cross-sectional views of a thermally expandable device positioned within the aligned ends of two pipes according to the present invention; FIG. 2 is a perspective view of a sleeve member suitable for use with the present invention; 3 is a cross-sectional view of another form of insertion sleeve member suitable for use in the present invention; FIG. 4 is a cross-sectional view of another form of sleeve member suitable for use in the present invention; FIG. FIG. 6 is a perspective view of an auxiliary insertion ring used in the sleeve member of FIG. 7; FIG. 7 is a perspective view of another sleeve member used in the invention; FIG. , FIG. 8 is a perspective view of an auxiliary insert member used in the sleeve member of FIG. 7. 69... Tubular member, 70... Heat recovery member, 71... Midpoint, 72... Sleeve, 73... Pore , 74...Sleeve, 75...Thin flat part, 81...
Sleeve, 82... Thin flat, 109...
... Auxiliary sealing ring, ]11 ... Insertion sleeve, 112 ... Pore, 113 ... Auxiliary member, 114 ... Teeth, 115 ... ...ear, 1
16...Groove.

Claims (1)

[Claims] 1. A pipe fitting device comprising a thermally expandable member made of a memory metal and a sleeve member located outside the thermally expandable member, the sleeve member being in contact with the thermally expandable member. or the thermally expandable member is positioned to contact the thermally expandable member when expanded to form a bond between the device and the tube to be mated, and the sleeve member A pipe fitting device, characterized in that means is provided on the main surface for ensuring an airtight seal between the device and the pipe to be connected.