GB2287078A

GB2287078A - Ductile steel pipe

Info

Publication number: GB2287078A
Application number: GB9426107A
Authority: GB
Inventors: Matamala Juan Bautista; Mora Miguel Sune
Original assignee: MORA CONST MEC
Current assignee: MORA CONST MEC
Priority date: 1993-12-22
Filing date: 1994-12-22
Publication date: 1995-09-06
Also published as: ES1026652U; ITRM940224V0; GB9426107D0; FR2714141A1; DE9420444U1; ES1026652Y; PT9110T; ITRM940224U1; PT9110U; IT233757Y1

Abstract

A steel pipe with flexible properties for the conveyance of fluids includes a stainless steel tubular element 1 with integral end connectors 3, 4 which enable it to be joined to other elements in a system and has on its outer surface a helicoidal thread 9 which extends without any intermediate gaps, from the connector of one end to the connector at the other end of the pipe. <IMAGE>

Description

DUCTILE STEEL PIPE FOR THE CONVEYANCE OF FLUIDS This invention relates to a new steel pipe for the conveyance of fluids which incorporates novel characteristics and inventive features in comparison with currently known pipe design.

The conveyance of fluids require pipes with properties of both mechanical and chemical resistance to the fluids conveyed, and the fluids conveying system needs properties of physical flexibility to ensure the efficient operation of the system in practice. For this reason, many and varied types of pipes for fluids conveyance have been introduced, and particular mention should be made of pipes manufactured from rubber or rubber by-products, plastic pipes and mixed material pipes, the last being composed of a rubber core or core of similar material and an outer flexible steel casing.

In other instances, elastomer pipes with an outer sheath or coat of interwoven steel fibres are used which make them highly resistant and flexible.

Pipes that are currently known do not easily combine the properties of flexibility, watertightness and appearance. It is therefore impossible to avoid high-cost pipes if adequate mechanical and chemical resistance as well as good flexibility and an acceptable external appearance are required at the same time.

Copper pipes with transversal grooves, which improve the flexibility of a simple copper pipe, have also been introduced, but they have limitations owing to the relative susceptibility of copper to certain types of chemical attack, for example, environmental corrosion in domestic systems in kitchens and bathrooms. These externally grooved copper pipes present a serious problem of soiling and unsightly discoloration, which is increased by chemical attack which is simply the result of the environment, which is even more noticeable in pipes used in kitchens and bathrooms and in similar systems. Moreover, the outward appearance of copper pipes provides a striking contrast to the objects and decorations used in kitchens and bathrooms, which precludes their use as visible pipes unless they are painted, which is not an ideal solution and which adds considerably to their cost.

This invention provides highly novel characteristics and solves the foregoing problems that beset currently known pipes for fluids conveyance.

The steel pipe which is the object of this invention is essentially characterized in that it is constructed from a single piece of preferably annealed stainless steel of an appropriate wall thickness and which has connectors that can be joined to other fixed elements relating to fluids, such as outlets, taps, etc., and characterized in that over the whole of its outer surface is a helicoidal thread which starts at the very end of the pipe, that is, without any intermediate gaps, which enables the pipe to be fitted around any bends or curves that may be present when installing fluids conveyance systems, especially those in kitchens and bathrooms. It has been observed that the characteristic of the thread continuing right to the end connectors of the pipe is a very important one, since this has been shown in tests to be an essential characteristic of the pipe' s flexibility, enabling it to be curved accurately from the very beginning of the connectors.

The angle of the helicoidal thread will vary depending on the characteristics of the pipe.

The wall thicknesses will also vary, and it is recommended that the wall thickness is not less than approximately 0. 3 mm; the preferred thickness is 0. 5 mm.

The ability of the pipe to curve will vary according to its size, although in tests it was observed that optimum values were obtained with radii of curvature that were at least about one third the length of the pipe.

In some instances, the angle of the thread in relation to the perpendicular at the pipe's-axis may give nil values, resulting in transversal grooves, whilst in other instances this angle may be gO , that is, in the form of simple longitudinal grooves.

If the pipe which is the object of this invention is manufactured from stainless steel it may be used directly in any bathroom or kitchen siting or in other visible systems without detracting from any decorative features. In this way, an original effect in pipes for the conveyance of this type of fluid will be achieved as they can be used without requiring to be painted or given any other decorative finish.

An example of an application of a pipe for fluid conveyance according to this invention is described below, and the preferred practice is shown in the attached diagrams.

Figure 1 shows a complete longitudinal section of a pipe constructed according to this invention.

Figure 2 shows in detail a longitudinal section of a pipe wall in a curved position.

Figure 3 shows a transverse section of the pipe.

Figure 4 shows diagrammatically an installed pipe according to this invention.

In the preferred practice shown, the pipe according to this invention, generally indicated as (1), has connectors which, as an example, are shown as (2) and (3). The former is a collar designed to fit inside a nut or a connecting piece (4), whilst the connector (3) is shown with a groove (5), in which a toroidal joint or other similar element is housed (6). These connectors (2 and 3) may have conical sections like that at the connector (2), indicated by (7), or like that at connector (3), indicated by (8), which are designed to achieve a better fit of any elements required to be connected to pipe (1). A characteristic of the pipe (1) is that it is manufactured from stainless steel which has preferably been annealed in order to improve its flexibility, with an outer helicoidal thread (9), the pitch of which will be defined by the angle a shown between the edge of the thread and a perpendicular to the axis of symmetry (10) of the pipe.

The angle a will vary according to the dimensions of the pipe and its application, and may range from 0 to 90 , corresponding to the extreme cases of transversal or longitudinal grooves.

The curvature of the pipe may vary according to the pipes dimensions. Figure 4 shows diagrammatically a connection of two units (11 and 12), of the type normally used in bathrooms and kitchens, connected by a pipe (13) according to the present invention, which remains curved around the contour of an intermediate obstacle, diagrammatically represented as (14), so that it is kept away from the obstacle.

In the curvature of the tubular element the radius of curvature may vary, although it has been observed in tests that optimum values are obtained for radii of curvature (15), Figure 2, that are approximately two and a half times the nominal diameter of the pipe, which is equivalent to its being curved into a complete semicircle.

The wall thickness of the pipe will also vary, although tests carried out show that this thickness, i. e. that at region (16), Figures 2 and 3, should not be lower than 0. 3 mm, normally ranging from 0. 3 mm to 1. 0 mm, with a thickness of about 0. 5 mm being preferred.

The foregoing description is illustrative but not limitative, and it should be understood that those skilled in the art may introduce many variants in the pipe according to this invention without deviating from the required characteristics.

The essence of this invention may be translated into practice in forms that differ in detail from that given as an example in the foregoing description and to which the protection being claimed will equally apply. The pipe may therefore be constructed in any shape or size from the most appropriate material and still remain within the spirit of the claims.

Claims

1. A ductile steel pipe for the conveyance of fluids characterized in that it includes a stainless steel tubular element with integral end connectors which enable it to be joined to other elements in a system and has on its outer surface a helicoidal thread which extends without any intermediate gaps, from the connector of one end to the connector at the other end of the pipe.

2. A ductile steel pipe for the conveyance of fluids as claimed in Claim 1, characterized in that the tubular element is manufactured from annealed stainless steel.

3. A ductile steel pipe for the conveyance of fluids as claimed in Claim 1, characterized in that the angle between the flank of the thread and the perpendicular to the axis of the pipe ranges from 0 to 90'.

4. A ductile steel pipe according to claim 1, substantially as herein described.

5. A ductile steel pipe substantially as herein described with reference to the accompanying drawings.