Rotatable fire sprinkler fitting

A fire sprinkler fitting has a cylindrical body and an insert. The insert has an inner end which is disposed within a proximal portion of the bore, such that the outer end protrudes beyond the open bore end by a distance D. The outer end has internal threads which are sized and dimensioned to accept and retain a fire sprinkler therein. The insert is rotatable within the body without effecting the distance D.

BACKGROUND OF THE INVENTION

Fire sprinkler systems are increasingly recognized as necessary safety features in the construction of new buildings and in the upgrading of existing buildings. There is a problem, however, in the installation of fire sprinkler systems.

Many styles of fire sprinkler heads have built-in deflectors that require rotational orientation of the sprinkler head to correctly position the deflector to produce the desired spray pattern when the head operates. All prior art fire sprinkler heads are attached to the piping mains by tapered pipe threads designed to produce a water tight seal using the interference of the tapered threads, plus either or both of a thread tape or thread paste. Thus, it can be appreciated that proper orientation of prior art sprinkler heads can usually only be accomplished by under-tightening the sprinkler heads or over-tightening the sprinkler heads. Overtightening of the tapered pipe threads produces interference between the mating threads, resulting in distortion of the mating parts. Undertightening over the tapered pipe threads can produced leaks.

Accordingly, there is a need for a fire sprinkler fitting which avoids the aforementioned in the prior art.

SUMMARY

The invention satisfies this need. The invention is a fire sprinkler fitting comprising (a) a cylindrical body defining a bore with a center line, an open bore end, the bore having a distal portion adjacent to the open bore end and a proximal portion spaced apart from the open bore end, and (b) an insert having an outer end and an inner end, the inner end being disposed within the proximal portion of the bore such that the outer end protrudes beyond the open bore end by a distance D, the outer end having internal threads which are sized and dimensioned to accept and retain a fire sprinkler therein. In the invention, the insert is rotatable within the body without affecting the distance D.

DETAILED DESCRIPTION

The invention is a fire sprinkler fitting10comprising a cylindrical body12and an insert14disposed within the cylindrical body12.

The cylindrical body12defines a bore16with a centerline18and an open bore end20. The bore16has a distal portion22adjacent to the open bore end20and a proximal portion24spaced apart from the open bore end20. The cylindrical body12also defines an inlet end26having an open inlet bore28.

The proximal portion24of the bore16defines a shoulder29disposed in a plane which is perpendicular to the centerline18of the bore16.

In the embodiment illustrated in FIGS.1and4-6, the outer side surface30of the body12is smooth and is sized and dimensioned to match the internal bores31of standard pipe fittings33. Because the outer side surface30is smooth and is sized and dimensioned to match the internal bores31of standard pipe fittings33, the fitting is easily disposed within the internal bores31of standard pipe fittings used in fire sprinkler systems.

In the embodiment illustrated inFIGS. 7 and 8, the inner side surface32of the inlet bore28is smooth and is sized and dimensioned to match the exterior dimensions of standard pipe exteriors. Because the inner side surface32of the inlet bore28is smooth and is sized and dimensioned to match the outer dimensions of standard pipe exteriors, the embodiment of the fitting10illustrated inFIGS. 7 and 8is easily attached to the end of a water supply pipe.

The cylindrical body12is typically made from a polymeric material, such as PVC or CPVC. However, cylindrical bodies12made from other materials, such as from a metal, can also be used.

The insert14has an outer end34and an inner end36. The inner end36is disposed within the proximal portion24of the bore16a distance L from the open bore end20, such that the outer end34protrudes beyond the open bore end20by a distance D.

The inner end of the insert14defines a circumferential flange37which abuts and is retained by a shoulder29defined within the proximal portion24of the bore16within the cylindrical body12.

The outer end34of the insert14has internal threads38which are sized and dimensioned to accept and retain a fire sprinkler therein.

In the embodiments illustrated in the drawings, the internal threads38are sized so as to not produce interference with the exterior threads40of a fire sprinkler head42, but to merely engage and hold the sprinkler head42axially against a first elastomeric seal44. In the embodiments illustrated in the drawings, the first elastomeric seal44is an O-ring. Other types of elastomeric seals, such as elastomeric gaskets, can be used as the first elastomeric seal44. Note that the first elastomeric seal44in the embodiment illustrated inFIG. 8is adapted to be disposed beneath the center of the exterior threads40of the fire sprinkler head42.

Alternatively, the internal threads38can be sized and dimensioned to produce interference with the exterior threads40of a sprinkler head42. In this alternative embodiment, no elastomeric seal44is needed at the base of the insert14.

The insert14is disposed within the body12such that the insert14is rotatable with respect to the body12without effecting the distance D. Preferably, the insert14is rotatable within the body12only by application of a torque of at least about 2½ ft-lbs, typically greater than 5 ft-lbs, and most typically between about 5 ft-lbs and about 60 ft-lbs.

In the embodiments illustrated in the drawings, the seal between the insert14and the body12is reinforced with an optional second elastomeric seal46. The second elastomeric seal46can be an elastomeric gasket, an elastomeric O-ring or other form of elastomeric seal known to those in the art.

The insert14is typically made from a metal, such as a brass. However, the insert14can alternatively be made from a polymeric material, such as a plastic, so long as the polymeric material has a melting point at least 10° F. greater than the melting point of the body12.

Where the body12is made from a polymeric material, a collar48, typically a metal collar, can be disposed around the body12to reduce stress on the body12by the insert14. The collar48is sized so as to not cover an undue portion of the over-molded plastic. Covering an undue portion of the over-molded plastic unnecessarily increases operating torque. Thus, the collar48is preferably disposed around the body12such that the collar48extends around the distal bore portion22, but not around the proximal bore portion24. Preferably, the collar48also provides a wrench head50with gripping flats52for conveniently retaining the collar48(and the body12) when the insert14is rotated.

FIG. 6illustrates the installation of the embodiment of the invention illustrated inFIGS. 1,4and5into the internal bore31of a fitting33used in a water supply header. In a first step, the fitting of the invention10is disposed within the internal bore31of the water supply header fitting33, and is retained therein with an appropriate glue or cement. A fire sprinkler head42can be disposed within the outer end34of the insert14, either before or immediately after this first step. After the fitting10has been securely disposed within the water supply header fitting33, wrenches54can be used to rotate the insert14with respect to the body12to optimally adjust and orient the sprinkler head42.

As can be seen from the foregoing discussion, the inserts of the invention allow the installer to attach fire sprinklers to fire sprinkler water pipes without having to use specially designed fire sprinkler attachment fittings. Also, the inserts of the invention allow the installer to install fire sprinklers into fire sprinkler piping in such a way as to consistently achieve optimum attachment alignment and tightening.

Having thus described the invention, it should be apparent that numerous structural modifications and adaptations may be resorted to without departing from the scope and fair meaning of the instant invention as set forth hereinabove and as described hereinbelow by the claims.