GB2278169A

GB2278169A - Cast pipe fittings

Info

Publication number: GB2278169A
Application number: GB9407366A
Authority: GB
Inventors: Heinrich Strafhoff
Original assignee: Georg Fischer Rohrleitungssysteme AG
Current assignee: Georg Fischer Rohrleitungssysteme AG
Priority date: 1993-04-22
Filing date: 1994-04-14
Publication date: 1994-11-23
Anticipated expiration: 2014-04-14
Also published as: GB2278169B; ITMI940722A1; FR2704298B1; IT1269320B; CH688063A5; ITMI940722A0; ATA68894A; DE4313151C1; GB9407366D0; AT401096B; FR2704298A1

Description

2278169 SHAPED ARTICLES FORMED BY CASTING 1 The invention relates to

shaped articles formed by casting and is concerned with such articles, for example pipe fittings, having at least one connection end whereby they can be connected to other components.

It is known to provide the connection ends of cast pipe fittings with inner and/or outer screw threads for connecting pipe lines to the fittings. However, these require expensive mechanical processing after casting. Furthermore, in the case of a fitting constructed as a curve or T-piece, it is only possible to screw the fitting to a pipe already secured to a wall when there is sufficient space available to rotate the fitting and thereby screw it to the pipe.

Pipe line systems based on metal pipes are known which include components such as pipes and pipe fittings which are joined tightly together by means of push-in connectors acting in a force-fitting manner.

Such push-in connectors comprise a generally cylindrical housing into the open ends of which the connection ends of the components to be connected can be pushed. The housing is then clamped around the of the components by means of one or more clamping bolts. The housing includes a resilient sealing element which contacts the outer surfaces of the component ends to provide a fluid tight seal therebetween and also clamping members which mechanically engage with the outer surfaces of the component ends to retain the ends in the connector by resisting axial movement of the ends with respect to the connector. Push-in connectors of this type are described in DE-C-2760127.

However, components conventionally formed by casting cannot be used with such connectors and thus pipe line systems of the above type can only be used or 1 constructed to a limited degree.

It is an object of the present invention to produce cast shaped articles such as pipe fittings and other like components which can be used in pipe line systems of the above type in a simple and costeffective manner.

According to the present invention there is provided a cast shaped article having at least one connection end which is free of flash and which has a length (L) which is from 0.5 to 1.2 times its outer diameter (D).

For a better understanding of the invention and to show how the same may be carried into effect, reference will now be made, by way of example, to the accompanying drawings, in which:- Fig. 1 is a plan view of a pipe fitting in the form of a 900 bend formed of cast material and joined to a pipe by means of a push-in connector (shown in partial section), Fig. 2 is a plan view of a pipe fitting in the form of a T-piece formed of cast material, Fig. 3 is a partially sectioned plan view of a pipe fitting in the form of a reduction piece formed of cast material, and Fig. 4 is a section of a pipe fitting in the form of a stop end formed of cast material.

Referring now to Figure 1, the pipe fitting has two plug-in connection ends 2 which are flared in that they increase conically in diameter towards the outer extremity 3. The angle of the flare a may be from 0.5 to 2% preferably 1. This increase in diameter towards extremity 3 improves the axial tensile strength of the plug-in connection. (Alternatively, the connection ends may be of cylindrical construction of constant diameter).

The fitting is formed from a casting material by a A casting process and each connection end 2 is prepared by removing the flash, resulting from the casting process, from the outer surface of the fitting for a length L which corresponds to 0.5 to 1.2 times the external diameter D of the end 2.

As can be seen in Fig. 1, the fitting can be connected to a metal pipe 5 by means of a push-in connector. The connector 4 comprises a housing 6 into which the end 2 of the fitting and the end of pipe 5 can be inserted so that the housing 6 envelops the ends. Located within the housing 6 is a rubber sealing sleeve 7 and two clamping members in the form of high tensile steel coils 8 arranged to co-operate with the ends to be joined. The housing 6 is clamped around the ends by nut and bolt assembly 9 so that the sleeve 7 seals against the outer surfaces of the ends to provide a fluid tight joint and the coils 8 mechanically engage with the outer surfaces of the ends to prevent the ends being axially withdrawn from the connector 4.

Ordinarily, it is sufficient if length L is about 0.5 to 0.6 times the outer diameter D and preferably therefore the connection ends are of this length for reasons of economy of material.

If cast fittings are to be directly joined together by means of such a connector, it is advantageous if at least one of the fittings has a connection end of length L which is about 1.2 times the outer diameter D so that the connector can be completely slipped over that end prior to being partially withdrawn, once the connection end of the other fitting is in position, so as to envelop both connection ends.

The fitting shown in Fig. 1 can, alternatively, be designed to have a larger radius whereby the usual 300, 45' or 60' bends (either angled or curved) can also be provided with plug- in connection ends of this type.

1 Also the two ends 2 can have corresponding different outer diameters for use with pipes or other components of different diameters.

Referring now to Fig. 2, there is shown a cast T- piece 10 having three connection ends 2 of the type described with respect to Fig. 1. If desired, the connection ends of the T-piece can be of different diameters.

Referring to Fig. 3, there is shown a cast reduction piece 20 having two connection ends 2 of different diameter. Otherwise the connection ends are as described in Fig. 1.

Referring to Fig. 4 there is shown a cast fitting in the form of a closure 30 having a connection end 2 of the type described in Fig. 1. The closure can serve as a cap or a plug, as shown.

The cast articles of the invention may be formed of various metallic casting materials and are preferably made of malleable cast iron, either plain (bright-finished) or ungalvanized, or galvanized. Furthermore, the articles may be made of cast spherical graphite, gray cast iron, unalloyed cast steel, or alloyed cast steel.

In addition to the sand mould casting process, the articles.may be made by the precision casting process, which has also become known as the fine casting (high quality casting) or exact casting process. This is particularly the case when using cast steel.

By providing the shaped articles with connection ends according to the present invention they can be tightly joined, by push-in connectors in a forcefitting manner, to pipes or to a further shaped article. Thus, for example, shaped articles of the most varied shapes, which can be produced costeffectively, can be easily joined by plugging or clamping to pipes already arranged on, or in a recess -5 of, a wall.

1

Claims

CLAIMS:

1. A cast shaped article having at least one connection end which is free of flash and has a length (L) which is from 0.5 to 1.2 times its outer diameter 5 (D).

2. An article according to claim 1, wherein the connection end is cylindrical and of constant diameter.

3. An article as claimed in claim 1 wherein the connection end is flared in that its diameter increases conically towards the extremity of the end.

4. An article as claimed in claim 3 wherein the angle (a) of flare is from 0.5 to 2.

5. An article as claimed in any preceding claim which is a pipe fitting in the form of a bend.

6. An article as claimed in any one of claims 1 to 4 which is a pipe fitting in the form of a T-piece.

7. An article as claimed in any one of claims 1 to 4 which is a pipe fitting in the form of a reduction piece having connection ends of different diameter.

8. An article as claimed in any one of claims 1 to 4 which is a pipe fitting in the form of a closure.

9. An article as claimed in any preceding claim and made of malleable cast iron.

10. An article as claimed to 8 and made of cast spherical

11. An article as claimed in any one of claims 1 graphite.

in any one of claims 1 to 8 and made of alloyed or unalloyed cast steel.

12. An article as claimed in any preceding claim and made by the precision casting process.

13. An article as claimed in claim 1 substantially as hereinbefore described with reference to and as illustrated in any one of Figures 1 to 4 of the accompanying drawings.

14. In combination, an article as claimed in any one of the preceding claims and a push-in connector connecting the article to another component.

Y 1

15. The combination of claim 14 wherein the component is a metal pipe.

16. A pipe line system including the article or combination of any preceding claim.

17. The use of a shaped article as claimed in any one of claims 1 to 13 in combination with a push-in connector in a pipe line system based on metal pipes.