Patent Application
20100133808
The present invention relates generally to metallic connectors which are intended to be used to join metallic parts together by deformation.
In one embodiment, the invention comprises a metallic connector for connection to a metallic pipe or to provide a connection between two or more metallic pipes.
In another embodiment, the invention comprises an assembly comprising a metallic element, which is preferably tubular, that is joined to a metallic connector, and a method of assembly.
In the building trade, it is well known that piping is used to distribute various fluids such as water and gas. Such piping typically comprises sections of rigid metal pipes, that are usually made of steel, which are threaded together using connectors, that are usually made of cast iron.
The pipes and the connectors are usually screwed together. Typically, the connector (such as an elbow, a coupling, or a T-fitting) has threads which are provided at the ends during manufacture of the connector. However, typically the pipe is first cut to the right length in the field during assembly of a piping system and then the ends of the pipe are threaded. Once the ends of the pipe have been threaded, one end of the pipe can be screwed into the connector.
This method of connecting pipes is very common, but is not particularly easy or economical. For example, a threading machine (or some other special piece of equipment) is normally used at the workplace to thread the ends of the pipes. Such threading machines are usually quite large and difficult to move.
Furthermore, once the ends of the pipe have been threaded, the threads are typically wound with Teflon or with hemp or with some other sealing material to make the joint with the connector watertight, and this procedure takes additional time during assembly of a piping system.
These steps are generally repeated for each of the sections of pipe in a piping system so that the various components may be connected in a professional manner and so that the connections are watertight and so that the piping assembly has the proper size and configuration.
The consequence is that the conventional method for connecting metallic pipes generally requires a very long time and the preparation of the threads at the pipe ends is relatively difficult. In addition, various problems such as leaks, stripped threads, and structurally weak connections may arise if a pipe has not been threaded properly.
In a prior art patent document (WO-03058108), the suggestion was made to connect pipes and connectors not by threading but by pressing them together. In this way, connections can be made quickly and simply due to the use of an automatic press which is positioned around the connector.
Furthermore, according to this patent document, the connection generally provides a consistent level of quality throughout various connections, since generally the only variable is the amount of pressure to be applied to the connector and this pressure is relatively constant for the same connector dimensions.
However, although the system of patent document WO-03058108 is relatively innovative and simple, there are still various difficulties and disadvantages provided by such a system. For example, in this system, the length of the pipe is understood to be relatively important and in certain conditions during assembly of a piping system it may be appropriate that a pipe having a greater (or shorter) length needs to be inserted into the connector.
It is an object of a preferred embodiment of the present invention to provide a metallic connector which may be connected with the end of a metallic item—preferably a pipe—in a manner which is relatively simple, rapid, and watertight, in order to avoid problems found with traditional connectors.
It is another object of a preferred embodiment of the present invention to provide a connection in which a metallic part—preferably a pipe or tubular member—is connected with a metallic connector to provide a connection which is relatively simple, rapid, and watertight, in order to avoid problems found with traditional connection arrangements.
It is yet another object of a preferred embodiment of the present invention to provide a method for assembling a connection in which a metallic part—preferably a pipe or tubular member—is connected with a metallic connector to provide a connection which method is relatively simple, rapid, and watertight, in order to avoid problems found with traditional connection methods.
With reference to
The metal connector 1 comprises a body with at least one female housing 2. The female housing is formed by an inner wall which is configured to receive the end section 4a of the metal pipe 4 to be connected.
In the preferred embodiments as shown in the Figs., the metal pipe 4 which is to be connected to the metallic connector 1 preferably has a substantially circular cross-section. Similarly, the female housing 2 of the metallic connector 1 also has a substantially circular cross-section.
With continued reference to
With reference now to the items seen in
With specific reference to
Preferably, at least a specified length L of either end of metal pipe 4 (comprising the end section 4a) can be inserted into the basically cylindrical body of female housing 2. The specific length L corresponds to the axial length of a portion of the female housing having a diameter D1 which is slightly greater than the inner diameter D of the connector.
In the preferred embodiments, the metallic connector 1 includes extensions or stops 3 which are provided on or form part of an inner wall of the metal pipe 1. These extensions serve as stops to prevent the metal pipe 4 from being inserted too far into the metallic connector. As can be seen from the Figs., the stops 3 are positioned so that they are further inside the metallic connector 1 than the minimum length L of pipe which is to be inserted into the female housing 2. When these stops 3 are reached by the length of pipe 4, at least the minimum length L of the metal pipe 4 has been inserted into the female housing 2.
With reference to
With reference again to
A significant feature of the preferred embodiments of the present invention is that an end of the metallic connector 1 will have a retaining ring 6, which—
Significantly, at the completion of the connecting operation by pressing in and deforming the female end of the metallic connector 1 and the end section 4a of the pipe 4, the retaining ring 6 is pressed very hard against the external wall of the end section 4a of the pipe 4, such that the end section 4a of the pipe 4 is held very firmly in place inside the female housing 2, and therefore inside the metallic connector 1.
The retaining rings 6 are preferably made of harder material than the material of the pipes or piping 4, so that during the deformation operation of the metallic connector 1 and the end section 4a of the pipe 4, the aforementioned retaining ring 6 also deforms the end section 4a of the pipe 4 and makes a slot about a circumference of the pipe end section 4a and the retaining ring is slightly inserted into the wall of the pipe 4. This means that the pipe 4 will be firmly connected to the metallic connector 1.
According to the preferred manufacturing method, the aforementioned retaining ring comprises only a portion of a complete ring. In other words, the retaining ring is preferably open, i.e. with a cut or gap provided somewhere along its circumference (see,
As shown in the preferred embodiments, the retaining ring 6 has an inner diameter so that (before the female end of the metallic connector 1 is compressed), the retaining ring will readily fit around the end 4a of the metal pipe 4. Preferably, the retaining ring is made of stainless steel.
The retaining ring 6 is preferably slotted firmly into the female housing 2, at a certain distance from the internal radial bushing or shoulder 5 at the end of the female housing. Forcing the open retaining ring 6 into the female housing 2 (i.e., by compressing the diameter of the retaining ring during insertion into the female housing 2), facilitates that the retaining ring 6 will be positioned properly inside the female housing 2, and also facilitates that the retaining ring 6 will not accidentally fall out from the metallic connector 1 when the end section 4a of the pipe 4 is inserted into the female housing. To keep the retaining ring 6 properly in place inside the female housing 2, an internal radial bushing (or preferably four internal radial bushes spaced apart by ninety degrees) are made generally at the outermost end of the inside of the female housing. An advantage of this internal radial bushing arrangement is that it can be made by caulking at staggered locations about the end of the housing, which are positioned ninety degrees apart. Of course, if six caulking locations are provided, the locations will be sixty degrees apart.
The caulking locations may be provided by punching a series of slots at the opening of the female housing of the metallic connector.
Another aspect of the preferred embodiments is that an annular seal member 7 is provided axially between the internal radial bushing or shoulder 5 and the retaining ring 6. The shoulder 5 keeps the annular sealing member 7 from being pushed into the metallic connector upon insertion of the pipe end. The annular seal member 7 forms a watertight connection with the outer surface of the end 4a of the metal pipe 4 and the inner surface of the female housing 2 of the metallic connector 1, after the female housing has been compressed about the end of the metal pipe.
The outer circumference wall of this annular seal member 7 is preferably in contact with the inside wall or inner surface of the female housing 2 and the inner circumference wall of the annular seal member 7 is preferably in contact with the outer wall or outer surface of the end section 4a of the pipe 4. Although the outer circumference wall and the inner circumference wall of the annular seal member 7 are curved in the circumferential direction, the walls are preferably relatively flat in the axial direction so that contact between the walls and the respective surfaces of the female housing and pipe end is better. The annular seal member 7 preferably has an axial length which is several times longer than the thickness of the retaining ring 6 (see,
Significantly, the internal radial bushing or shoulder 5 and the open or cut retaining ring 6 hold the annular seal member 7 in a proper position with regard to the female housing 2, both before and after the insertion of the end section 4a of the pipe 4 in the metallic connector 1, as well as after the deformation operation has been completed. The metallic connector 1 is preferably made of cast iron, which is relatively inexpensive. Preferably, after being formed, the metallic connector 1 is heat-treated so that it is tensile and ductile enough to allow the deformation operation to be carried out properly.
The metallic connector 1 is preferably made of malleable white heart cast iron (UNI EN 1562) with a maximum percentage chemical composition preferably of: C 0.20%; Si 0.95%; Mn 0.65%; P 0.05%; S 0.20%. The mechanical properties of the malleable white heart cast iron are preferably: Rp0.2 [MPa] 220; Rm [MPa] 400; and A min. 5%. White heart malleable cast iron is preferred because of its ability to be deformed without cracking. The cast iron connectors are preferably subjected to a suitable heat treatment under a controlled atmosphere and at an appropriate high temperature to provide an appropriate decarburization and malleability.
The metal connector preferably has a galvanized zinc coating provided by hot dip technology. The zinc coating is provided after the metallic connectors have been cleaned and washed in chloride acid and a phosphoric solution. The metallic connectors are dipped in a basin with melted zinc which is preferably 99.99% pure at a temperature of more than 600° C. The zinc coating will preferably completely cover the inside and outside of the metallic connector 1 to prevent oxide corrosion. After the zinc coating has been provided, the metallic connector will be provided with the annular seal member 7 and the retaining ring 6 which are preferably kept in place by the caulking bushings or shoulders provided at the outer (inside) end of the female housing.
The pipe to be connected to the metallic connector 1 is preferably formed of steel tube such as S 195T Number 1.0026 (EN 10255 Norm). The maximum percentage chemical composition of the piping is preferably: C 0.20%; Mn 1.40%; P 0.035%; S 0.030%. The mechanical properties of the piping are preferably: Rp0.2 [MPa] 195; Rm [MPa] 320-520; and A min. 20%.
The annular seal member 7 is preferably of an elastomer such as EPDM which has a working temperature range of −20° C. to 110° C. and a working pressure maximum of 25 bar at a temperature of 20° C. and 16 bar at a temperature of 100° C. These annular sealing members are suitable for use in sanitary plumbing, heating, air conditioning, fire protection and air compression piping systems.
The annular seal member 7 preferably has a radial thickness which is slightly greater than the radial thickness of the retaining ring 6 so that the annular sealing member is compressed when the female housing 2 is compressed about the end 4a of the metal pipe 4.
The cut retaining rings 6 are preferably made of stainless steel such as AISI 316L.
With reference now to
In piping systems for supplying heating gas for combustion, the annular sealing member 7 is preferably formed of an appropriate elastomer such as HNBR which has a working temperature range of −20° C. to 70° C. and a working pressure maximum of 5 bar.
With reference now to
With reference to
As can be appreciated by one of ordinary skill in the art upon reading the detailed description of the preferred embodiments, the metallic connector according to the present invention can be essentially any shape, and, if desired, can have one or more ends which are configured as shown in
Similarly, metallic connectors comprising the female housing according to the preferred embodiments of the present invention may have one end which is reduced in size (such as a reduced press elbow), or may have one end which is provided with either male threads or with female threads. In addition, the part to be connected to the metallic connector may be a nipple reducer with or without male or female threads, or a union fitting. Other plumbing fittings are, of course, suitable for use with the metallic connector according to the preferred embodiments of the present invention.
During assembly of a piping system, the elongation or contraction of the piping due to temperature variation should be taken into account as in the conventional piping systems such as those using threaded couplings. The pipe ends should be cut squarely and deburred to remove any debris prior to insertion into the female housing. If desired, a lubricant such as a silicon lubricant spray may be provided on the pipe end or inside the female housing.
If desired, the retaining ring 6 can be inserted into the female housing in some other way than that which is described above, and the open ring can also be maintained in the female housing in another way (for example, other than by the use of caulking).
With reference to
During assembly of a piping system, the female housing of the metallic connector 1 with the end of the pipe positioned within the female housing is positioned between the semi-circular portions 26, 28 of the jaw halves 20, 22. Then the distal ends of the jaw halves 20, 22 are urged apart by the press member to urge the semi-circular portions 26, 28 together and thereby compress the female housing of the metallic connector 1.
The press machine is preferably of suitable, conventional configuration and preferably has a minimum pressing force of 32 kN for piping sizes up to 1 inch.
Accordingly, when assembling a pipe joint comprising a metallic connector 1 and a pipe 4, the following stages may be applied—
Preferably, the jaws are provided with a raised feature on the semi-circular portions 26, 28 which will provide a visible marking on the outside of the female housing when the deformation is properly performed. This marking may comprise a dimple inserted into the female housing outer surface by the pressing jaws. If necessary, the pressing operation may be repeated on the same female housing without a likely damage to the metallic connector or to the pipe end. After compression, it may be possible to slightly rotate the metallic connector relative to the pipe end without harming the connection and without impairing the seal of the metallic connector with the pipe end.
The deformation of the female housing reduces the circumference of the female housing and results in the circumference of the retaining ring being reduced. In addition, the retaining ring deforms the inner wall of the female housing and the retaining ring is partially inserted into the inner wall of the female housing 2. At the same time, the retaining ring 6 deforms the outer wall of the end of the pipe and the retaining ring will be inserted slightly by deformation into the outer wall of the end section 4a of the pipe 4, thus locking the metallic connector and the pipe end together.
In addition, the compression of the female housing compresses the annular seal member 7 between the female housing and the pipe end to provide a water tight seal. If a copper annular ring is provided, the compression of the female housing also compressed the copper annular ring to form a gas tight seal between the female housing and the pipe end.
An assembly is thus obtained comprising a metallic connector 1 and a section of piping 4, which are locked together and relatively inseparable.
In the event of the metallic connector having one or mere additional ends which are to be connected in the same way, the above operations need only be repeated on the remaining female housings. It is easy enough to understand from the details above that the metallic connector in this invention is a solution to the technical problems for which this invention was designed, and at the same time the problems found with traditional methods. One advantage of the metallic connector in this invention is the structural simplicity with which it has been designed.
Clearly workmen in this field, when trying to comply with the specifications they have been given, may make all the changes they want to the connector and the various units as described above, for all of which there is protection as detailed in the claims below.
For example, the seals and retaining ring may be applied directly to the end of a pipe or another metallic item to be joined to the metallic connector, and then the female housing (without an annular sealing member and a retaining ring) may be positioned over the pipe end (having the annular seal member and the retaining ring) and then the female housing may be compressed as described above.
While the invention has been described in detail with reference to specific embodiments thereof, it will be apparent to one skilled in the art that various changes and modification may be made, and equivalents thereof employed, without departing from the scope of the claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| MI2006A002078 | Oct 2006 | IT | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/IB07/03258 | 10/29/2007 | WO | 00 | 1/4/2010 |
