Cast flange for pipe couplings

End clamp housing for attachment to a cylindrical body, the side end housing being a unitary metal casting comprising; an open annular base element provided with a first, ingoing flange at a first side of the base element and a second ingoing flange at a second side of the base element.

The second ingoing flange having a cross-section forming a loop extending outwardly beyond the base element; and a pair of clamp members projecting outwardly from the base element. The clamp members being positioned face to face and having an aperture to allow the insertion of a tightening element which can be operated to reduce the distance between the two ends of the open annular base element and thereby press an annular seal element against the outside of a pipe inserted through the seal clamp housing, which after release of the tightening element returns to its original dimensions.

More particularly, the invention provides an improved flange and its seal which is attachable to the external surface of a pipe and which can be used to eliminate a small leak if access to a pipe extremity is available. The flange housing isalso useful, again in combination with a seal element, for anchoring an adjacent item and for preventing fluid flow along the external surface of the pipe.

Pipe couplings and the clamps associated therewith are well known and have been manufactured by the present inventors for some years. The coupling comprises a central body member and two side clamps. A prior-art clamp is illustrated in FIG. 1. However there has now been found an improved manufacturing method which at the same time allows a design improvement and cost reduction of this item.

No directly relevant US patents were found. A 2-part seal clamp assembly for piping is disclosed by Friedrich et al. in U.S. Pat. No. 5,692,544, the purpose of which is to contain leakage between the large diameter end flanges of adjoiningco-axial pipes. Devices intended to seal pipe leaks are seen in US Patent Applications 2001/0008149 by D{grave over ( )}auria, No. 2004/0108010 by Gaston et al, and No. 2004/0118467 by Pirart. These disclosures do not however relate to the type of sealclamp which is the subject of the present invention.

A disadvantage of presently known end clamps of the steel band type is that the areas adjacent to the lug of the seal clamp, at each side are unflexible, straight and not concave, when viewed parallel to the seal clamp axis, whereas the sealoperates better when pressed inwardly by a concave surface. This defect in band clamps could be due to the nature of bending machines, the first and the last portion of a metal strip being curved not being bent, and remaining as flat as the originalmetal strip, probably because at the beginning and at the end of the bending process the workpiece is in contact with only 2 of the 3 rollers of the bending machine.

In a coupling of the type seen in FIG. 1 of the prior art design, and also in U.S. Pat. No. 4,463,975 to McCord, a sudden increase in thickness of the band when approaching the area of the lug is seen. This thickness results in sharp loss offlexibility near the lug, the outcome of which is that when in use this section will retain its original flat shape and thus fail to conform to the circular seal. More sealing pressure is thus required before a pressure-tight condition prevails. Applying high sealing pressure delays work on site and shortens the life of the flexible seal.

An open annular base element provided with a first, ingoing flange at a first side of said base element and a second ingoing flange at a second side of said base element, said second ingoing flange having a cross-section forming a loopextending outwardly beyond said base element; and a pair of clamp members projecting outwardly from said base element, said clamp members being positioned face to face and having an aperture to allow the insertion of a tightening element which can be operated to reduce the distance betweenthe two ends of said open annular base element and thereby press an annular seal element against the outside of a pipe inserted through said seal clamp housing, which after release of said tightening element returns to its original dimensions.

It has been found that the cast-iron flange clamp is no heavier than the sheet steel clamp which it now replaces. This is due to the use of thin walls reinforced by ribs on the outer face of the new clamp body.

Article Posted By : Isabella Xu zjflange is the leading manufactory and exporter of steel flange in Zhejiang Province of China.We are specialized in manufacturing and exporting Forged Steel Flanges and Pipe Fittings,our original factory was established in 1969 and have more than 40 years history in forging and exporting area.