Flange Connection for Quartz Tubes

The present invention relates to a flange connection to connect tubes of quartz glass or other quartz structural elements together, and more particularly to a universally useful flange connection which can be applied to tubes, pipes, and the like, of quartz glass or quartz materials regardless of size.

Tubular elements made of quartz glass or of quartz-ceramic materials are used in many applications, particularly in laboratories, and as components in various types of chemical and other apparatus. To connect tubes and pipes of such material together by flange connection causes difficulties since the material is brittle and difficult to shape. It has been proposed to connect tubular elements of quartz-type material together by forming flanges on the pipes or tubes to be connected, interposing a compressible sealing ring between the elements, and clamping the flanges to each other by means of external clamping rings, which surround the pipes or tubes. The flange may be formed as an externally projecting ring, or as a conical enlargement in the region of the flange connection. Such flange connections are illustrated, for example, in the prospectus Q-C 1/112, 1974, issued by Heraeus Quarzschmelze GmbH. The tubular element, during manufacture, has the ring-shaped flange thickening or projection formed thereon, the thickening projections then retaining the metal clamping flange which is placed thereabout. The flange projection itself can be made as desired in conical form, as a ring-shaped projection having an essentially rectangular cross section, or in other forms.

It has been found in operation that connecting tubes or pipes of quartz-type material by means of a projecting flange causes difficulties if the pipe has an inner diameter exceeding about 18 inches (45 cm), and having a wall thickness in excess of about 5/8 inch (15 mm).

It is an object to provide a flange connection suitable for quartz-type pipes, tubes, or the like, which is universally applicable regardless of diameter of the pipe or tubular element.

Briefly, the end portion of the pipe or tubular element is formed with a circumferential groove or recess. A spring wire, preferably of circular cross section, is snapped into the groove or recess, the wire fitting into the groove or recess only over a portion of its cross section, the remaining portion projecting therefrom. The remaining portion of the wire is clamped between a flange ring having an external flange with openings therethrough suitable for attachment to an external structure, and a counter or clamping ring, which is located at the side of the spring ring opposite the flange ring. The counter ring and the flange ring are connected by bolts to clamp the spring ring therebetween, the spring ring being held on the tubular element by its seat in the circumferential groove.

Two quartz elements can be connected together by using similar flange rings and clamping rings, and connecting the flange rings by bolts, preferably by spring-loaded bolts.

The single FIGURE is an axial cross section through two quartz pipes, connected together in accordance with the present invention.

The invention will be illustrated using as an example a butt connection of two pipes, in which one of the connections will be described in detail; the other is identical, and similar parts have been given the same reference numerals, with prime notations. A single explanation, therefore, suffices.

A pipe 1 is formed with a circumferential groove or recess 2. A spring ring 3 of essentially circular cross section is snapped into the recess 2. The spring ring, for example, is a split ring made of spring steel, nickel steel spring wire, or the like. The groove is of such thickness that the ring 3 fits into it with only a minor portion of its circumference, preferably less than half the diameter of ring 3--see the FIGURE. A flange ring 4 engages the projecting portion of the spring ring 3 on one side thereof; a counter ring 5 engages the projecting portion of the spring ring 3 at the other side thereof. The flange ring 4 and the counter ring 5 are clamped together by clamping bolts 6, located circumferentially around the connection at suitable distances from each other, for example placed uniformly around a circular pipe every 20.degree., 30.degree. or 60.degree., in dependence on the diameter of the pipe. The flange ring 4 and the counter ring 5 are axially clamped together, thus securely holding the spring ring 3 in the groove. The flange ring 4 as well as the counter ring 5 are formed with respective conical engagement surfaces 8 engaging the projecting portion of the spring ring 3 beyond a diametrical line parallel to the pipe 1 and exerting radially inwardly directed pressure on ring 3. The conical engagement surfaces 8 permit floating assembly, and adjustment independent of variations and tolerances of the outer diameter of the pipe 1 so that, upon tightening of the screws 6, uniform engagement pressure of the ring 3 within the groove 2 will be obtained. The inner clearance openings of the rings 4 and 5 is slightly larger than the maximum diameter of the pipe 1 to be expected, in the light of tolerances.

To connect two pipes together, two identical connections are placed on the respective pipe ends 1, 1', a sealing element of an elastic material 9 is placed between the butted ends of the pipes 1, 1', and the flange rings 4, 4' are connected by circumferentially positioned bolts 10, preferably spring-loaded by compression springs 11 to provide for resilient, but tight and secure engagement.

The rings 4, 5 can be made of any suitable metal, or may be made of a plastic material, reinforced by glass fibers. The spring rings 3 need not be made of metal; they may also be made in the form of cup springs or spring washers of resilient material which can be snapped into the circumferential recesses or grooves 3.

Before assembly, the rings 4, 5 as well as the rings 4', 5', of course, fit loosely around the respective pipes 1, 1'. The conical surfaces 8 are so arranged that the divergent surfaces on the rings 4, 5 face the respective pipe 1, 1'; thus, the side of the flange ring 4 which faces the counter ring 5 has a cross-sectional area adjacent the pipe 1 which is substantially less than the cross-sectional area remote therefrom; the counter ring 5, likewise, has a cross-sectional area adjacent the pipe 1 which is less than that remote therefrom. Preferably, the cone angle .alpha. of the flange ring 4, 4', is equal to the cone angle .beta. of the counter ring 5, 5'. The dimensions of the flange rings and of the counter rings are so selected that the cross section, in the region of the screw connection by the bolts 6, is a maximum. The angles .alpha. and .beta. are not critical; preferably, however, the angles are about 38.degree..

To connect two pipes 1, 1' together, the bores 7, 7' for bolts 10 preferably are slightly larger than the outer diameters of the bolts 10, and the bolts are tightened by compression of spring 11 by a nut secured thereto.

The arrangement has the advantage that tubular bodies of any desired diameter of quartz material, for example, can be connected without the requirement of forming a thickened region to make a flange which uses material difficult to handle and which is expensive. The flange can be easily and quickly connected on any tubular element. Tolerances of the outer diameter of the tubular element are readily accomodated, and a single size of flange ring 4, 4', and counter or clamping ring 5, 5' can be used regardless of tolerance variations of the pipes themselves.

To permit attachment of rings 4, 5, the rings themselves can be split radially and connected together by radially projecting connecting lugs, as well known.

The surfaces on the flange rings 4, 4' and on the counter rings 5, 5' which are remote from the respective opposite ring are, preferably, plane and flat to provide bearing surfaces for the connecting screws 6, and for the nuts and bolts, or springs, respectively, of the connecting bolts 10 and spring 11.