IE69544B1

IE69544B1 - A lining method and apparatus

Info

Publication number: IE69544B1
Application number: IE922072A
Authority: IE
Inventors: Michael O'connell; Noirin O'connell; James M Sheeran
Original assignee: Fordbrook Eng Ltd
Priority date: 1992-06-26
Filing date: 1992-06-26
Publication date: 1996-09-18
Also published as: GB2268116A; BE1004407A6; IE922072A1; GB9216222D0; GB2268116B

Abstract

A fitting such as a T-piece (1) is lined with plastics material (2) by inserting former sections (20, 21) fixed in end caps (25), and former rings (3), the former sections (20, 21) and end caps (25) being hollow and having connections (23, 26) for circulating cooling media and heating the assembly in an oven together with a pot containing plastics lining material before forcing the molten plastics material into the gap between the fitting (1), former sections (20, 21) and end caps (25) through sporge hole (40) by a ram. Cooling media are circulated through the end caps (25) and former sections (21, 22) to obtain a uniform layer of plastics lining 2 on the inner surfaces of the fitting.

Description

A lining method and apparatus The invention relates to a method and apparatus for lining a flanged fitting such as a T-piece, elbow piece, cross piece, reducer, valve or the like.

Various methods of producing plastic lined metal pipes are known. Such pipes are used to transport corrosive liquid. However, while attempts have been made to produce plastics lined pipe fittings such as T-pieces and the like, none of these methods have been entirely successful for economic and/or technical reasons.

This invention is therefore directed towards providing a method and apparatus for effectively and economically lining pipe fittings with plastics material.

According to the invention there is provided a method of lining a flanged fitting such as a T-piece comprising the steps of; inserting a former through the fitting, - 2 applying end caps to the flanges of the fitting, fixing the former to the end caps so that the former is spaced-apart from the inner wall of the fitting μ to define a gap for receiving lining material, heating the fitting, the former and the end caps in an oven, simultaneously heating lining material in the oven until the lining material is molten, injecting the molten lining material into the gap 10 between the former and the fitting, cooling the former with a cooling medium, and on setting of the lining material, removing the former from the fitting.

In preferred embodiment of the invention, former rings are 15 placed between the end caps and the flanges, each former ring defining together with the associated end cap a gap extending partially radially outwardly along the flage to receive lining « material for partially lining the flanges of the fitting.

In one embodiment of the invention a cooling media is circulated through the end caps. Preferably, different cooling media or the same cooling medium at different temperatures are circulated through the end caps and former to cool the lining material at different sites of the fitting. The cooling media may include a cold liquid such as water and/or a cold gas such as air or the like.

In one embodiment of the invention the fitting, former, end caps and plastics lining material are heated to a temperature of between 35O0C and 460°C.

In one embodiment of the invention the molten lining material is injected into the gap between the former and fitting by a ram means. Preferably, the molten lining material is injected into the lining gap at a pressure of up to 60 bar.

In one embodiment of the invention, the molten lining material is injected through a filter screen.

Typically, the fitting is of steel material and the lining material is selected from polytetrafluoroethylene, PFA perfluoro (alkoxyalkane) copolymer and FEP perfluoro (ethylene20 propylene) copolymer with the optional addition of antistatic Teflon* material.

* Teflon is a Registered Trade Mark - 4 The invention also provides a lined fitting such as a T-piece, elbow piece, cross piece, reducer, reducing flange, valve or the like whenever produced by the method of the invention.

In another aspect the invention provides an apparatus for 5 lining a flanged fitting such as a T-piece by the method of the invention, the apparatus comprising; end caps for the flanges of the fitting, a former supported by the end caps and extending through the fitting to define a gap for receiving lining material, the former and end caps having passageways for cooling media, In one embodiment of this aspect of the invention the apparatus includes former rings for interposing between the end caps and flanges of the fitting to define together with the associated end cap a gap extending partially radially outwardly along the flange for receiving lining material. In one case, the former comprises a number of interconnected former sections.

Preferably, the apparatus includes an oven for heating the fitting, former, end caps and plastics lining material.

Preferably, the apparatus also includes a ram means for injecting molten lining material into the fitting through a hole communicating with the gap defined between the former and the fitting.

In a preferred arrangement, the apparatus includes a nozzle through which the molten material is injected into the fitting.

Filter screen means may be provided through which the molten material is passed prior to injection into the fitting.

The invention also provides a lined fitting whenever produced using the apparatus of the invention.

The invention will be more clearly understood from the follow description thereof given by way of example only with reference to the accompanying drawings in which:Fig. 1 is a cross-sectional view of a fitting being lined with lining material, Fig. 2 is a diagrammatic exploded view of part of the apparatus used in the lining method, Figs. 3 and 4 are respectively perspective and crosssectional view of part of the apparatus, and - 6 Fig. 5 is a side, partially cross-sectional, view of a fitting lined using the method and apparatus of the invention. p Referring to the drawings, there is illustrated a fitting, in 5 this case a T-piece 1 which is lined with plastics material 2 using the method and apparatus of the invention. The T-piece is in this case an equal T-piece having a straight run ' section 5 terminating in end flanges 6, 7 and a perpendicular section 8 terminating in an end flange 9. The T-piece is of steel material and the lining 2 is of a suitable plastics material such as polytetrafluoroethylene, PFA, FEP with the optional addition of an antistatic Teflon (RTM).

The fitting 1 is lined by first inserting a former which in this case has a straight run section 20 and a perpendicular section 21. The former is of tubular cylindrical construction closed by ends 22 having connections 23 for circulating cooling media such as cold water or air through the former.

End caps 25 are provided for the flanges 6, 7, 9 of the Tpiece and these are also of hollow construction with connections 26 for circulating a suitable cooling medium through the end caps independently of the former. Annular » former rings are interposed between the end caps 25 and the respective flanges 6, 7, 9 which define together with the end caps 25 and the flanges a gap through which the lining material is allowed to flow to partially line the flanges 6, 7, 9 (as will be particularly apparent from Fig. 5) for mating with correspondingly lined pipe sections. The formers 20, 21, end caps 25, and annular former rings 30 may be assembled in any suitable manner. In this case, the former rings 30 are bolted to the respective flanges 6, 7, 9 by bolts 35 and bolts 36 bolt the end caps 25 and former sections 20, 21 together.

The fitting 1 includes an inlet sparge hole 40 through which plastics lining material is injected.

In the method of the invention, the former sections 20, 21 are first inserted through a fitting 1 and the end caps 25 and former rings 30 are fitted as illustrated. When the former end caps and former rings 30 are fitted, the arrangement is such that the former is spaced-apart from the inner walls of the fitting 1 to define a substantially uniform gap for receiving lining material.

The fitting with former, end caps, and former rings attached is then placed in an oven as is a pot containing granules of plastics lining material. The fitting and lining material are heated in the oven to a temperature of from 350°C to 460°C until the lining material is molten and the fitting is heated through. The lining material is the transferred to a ram arrangement having a nozzle through which the lining material is injected under a pressure of up to 60 bar into the fitting through the hole 14, the molten lining material filling the gap between the former sections 20, 21, end caps 20, former rings 30 and the fitting. The end caps 20 and former sections 20, 21 are cooled by circulating a cooling medium through the caps 25 and former sections 20, 21 in such a way as to facilitate substantially uniform setting of the lining material to provide a substantially uniform thickness of lining material throughout the fitting. When the lining is complete the fitting with the former sections 20, 21 and end caps 25 still in place is removed and allowed to set at room temperature. The former 20, 21 end caps 35 and former rings 30 are then removed to provided a lined fitting as illustrated in Fig. 5.

Preferably, an orifice plate or filter screen is provided for filtering material injected into the fitting.

The invention provides an effective and economical method and apparatus for lining fittings.

It will be appreciated that while the invention has been described with particular reference to the lining of a T-piece it may be applied to lining any suitable fitting such as a cross-fitting, a reducing T, an instrument T, elbows of <,* various angles such as a 90° or 45° elbow, a concentric or ./ eccentric reducer, a reducing flange and various constructions of valve.

The internal walls of the fitting may be provided with means for mechanically interengaging with lining material. For example, the walls may be provided with grooves or recesses into which the lining material flows for improved mechanical interengagement.

The invention is not limited to. the embodiments hereinbefore described with may be varied in both construction and detail.

Claims

1. A method of lining a flanged fitting such as a T-piece comprising the steps of f inserting a former through the fitting, 5 applying end caps to the flanges of the fitting, fixing the former to the end caps so that the former is spaced-apart from the inner wall of the fitting to define a gap for receiving lining material, heating the fitting, the former and the end caps in 10 an oven, simultaneously heating lining material in the oven until the lining material is molten, injecting the molten lining material into the gap between the former and the fitting, 15 cooling the former with a cooling medium, and on setting of the lining material, removing the t former from the fitting.

2. A method as claimed in claim 1 wherein former rings are placed between the end caps and the flanges, each former ring defining together with the associated end cap a gap extending partially radially outwardly along the flage to receive lining material for partially lining the flanges of the fitting.

3. A method as claimed in claim 1 or 2 wherein a cooling media is circulated through the end caps.

4. A method as claimed in claim 3 wherein a different cooling media or the same cooling medium at different temperatures are circulated through the end caps and former to cool the lining material at different sites of the fitting.

5. A method as claimed in claim 4 wherein the cooling media include liquids such as water.

6. A method as claimed in claim 3 or 4 wherein the cooling media include cold gas such as air.

7. A method as claimed in any of claims 1 to 6 wherein the fitting, former, end caps and plastics lining material are heated to a temperature of between 350”C and 460°C. 12

8. A method as claimed in any preceding claim wherein the molten lining material is injected into the gap between the former and fitting by a ram means.

9. A method as claimed in claim 8 wherein the molten lining 5 material is injected into the lining gap at a pressure of up to 60 bar,

10. A method as claimed in claim 8 or 9 wherein the molten lining material is injected through a filter screen.

11. A method as claimed in any preceding claim wherein the 10 fitting is of steel material and the lining material is selected from polytetrafluoroethylene, PFA perfluoro(alkoxyalkane) copolymer and FEP perfluoro(ethylene-propylene) copolymer with the optional addition of antistatic material. 15

12. A method substantially as hereinbefore described with reference to the accompanying drawings.

13. , A lined fitting whenever produced by a method as claimed in any preceding claim.

14. A fitting as claimed in claim 13 which is selected from 20 Tee-pieces, elbow pieces, cross pieces, reducers, reducing flanges and valves.

15. Apparatus for lining a flanged fitting such as a T-piece by the method as claimed in any of claims 1 to 12, the apparatus comprising; end caps for the flanges of the fitting, 5 former supported by the end caps and extending through the fitting to define a gap for receiving lining material, the former and end caps having passageways for cooling media, 10

16. Apparatus as claimed in claim 15 including former rings for interposing between the end caps and flanges of the fitting to define together with the associated end cap a gap extending partially radially outwardly along the flange for receiving lining material. 15

17. Apparatus as claimed in either of claims 15 or 16 wherein the former comprises a number of interconnected former sections.

18. Apparatus as claimed in any of claims 15 to 17 wherein the apparatus includes an oven for heating the fitting, former, end caps and plastics lining material.

19. Apparatus as claimed in any of claims 15 to 18 wherein the apparatus includes ram means for injecting molten lining material into the fitting through a hole communicating with the gap defined between, the former and 5 the fitting.

20. Apparatus as claimed in claim 19 including a nozzle through which the molten material is injected into the fitting.

21. Apparatus as claimed in claim 19 or 20 including filter 10 screen means through which the molten material is passed prior to injection into the fitting.

22. Apparatus substantially as hereinbefore described with reference to the accompanying drawings.

23. A lined fitting whenever produced using an apparatus as 15 claimed in any of claims 15 to 22.