The present invention relates to a plumbing fitting and particularly one for use with a fire suppressing sprinkler system and its method of manufacture.
Installation of sprinkler heads which utilize metal threads to a typical water system employed in fire suppressing systems typically involves threading the tapered metal threaded sprinkler head into a threaded polymeric socket, in turn, bonded to a polymeric water supply line using a bonding adhesive. If over tightening of the metal sprinkler head occurs, it can result in fractured polymeric sockets for receiving the fire sprinkler head or, if under tightened, water leaks can result. These problems exist, in part, because it is desirable to have the sprinkler heads specifically aligned to present a desired sprinkling pattern or, in some installations, an aesthetically pleasing common appearance. In order to do so, typically a sprinkler head wrench is employed to prevent damage to the sprinkler head during installation and approximately 25 to 50 foot-pounds of torque is applied to install the sprinkler head. Alignment of the sprinkler heads then frequently requires additional tightening as much as a quarter turn to properly align the sprinkler heads. In horizontally extending sprinklers, it is necessary for the sprinkler head deflector to be substantially horizontal and the sprinkler head fitting square to the receiving socket. Typical seals, such as O-ring type seals, have been problematical in such installations in which under tightening can cause leaks, while overtightening in an effort to obtain a seal can result in stripping or fracturing of the receiving polymeric threads of the water supply socket.
There remains a need for an improved plumbing fitting for receiving a sprinkler head which includes a seal shape that allows a sprinkler head to be mounted to a receiving socket of a fire suppression water supply line using a lower torque to achieve a seal, thereby preventing damage to the sprinkler head while providing a watertight seal and proper alignment of the sprinkler head with respect to other sprinkler heads and/or to the water supply line.
The present invention solves this need by providing an in-molded brass fitting received by a polymeric pipe socket, which is coupled to the water supply line. In one embodiment, a plumbing fitting for installing a metal fire sprinkler head to a polymeric water supply line is provided and includes a polymeric cylindrical fitting having an outer diameter at one end for extending into a water supply line and a second end molded around a threaded brass insert. The threaded brass insert includes an internal annular sealing surface, a first external annular groove spaced from one end for receiving an O-ring seal and receiving molded material from the over-molded cylinder fitting, and a second external annular groove spaced from the first annular groove for receiving molded material from the over-molded cylindrical fitting for sealably securing the brass insert within the cylindrical fitting. It also includes an annular tapered seal positioned within the brass insert and having a annular sealing surface abutting the annular sealing surface of the brass insert.
In another embodiment, an annular seal is provided for use in sealing a fire sprinkler head to a threaded fitting coupled to a water supply. The seal includes an annular body having a central opening defined by an outwardly tapered conical wall, with the conical wall terminating in a first annular surface at one end and a second annular surface at an opposite end. The seal has an outer surface including an inwardly tapered outer conical wall extending to the one end of the seal wherein the first annular surface sealably engages a threaded fitting and the second annular surface is sealably engaged by a sprinkler head.
A further embodiment of the invention includes method of manufacturing a fitting for coupling a fire sprinkler head to a water supply line including the steps of 1) providing a generally cylindrical threaded brass insert for threadably receiving a sprinkler head; 2) forming a first inwardly extending groove on an outer surface of the insert; 3) inserting an O-ring in the inwardly extending groove; 4) providing a second inwardly extending groove in said insert which is spaced from said first groove; and 5) molding a polymeric material in the shape of a coupling for attaching a fire sprinkler head to a water supply line over the brass insert, such that the polymeric material extends into said second groove.
The brass insert in a preferred embodiment of the invention receives a unique tapered seal which seats and forms a seal between the brass insert and the sprinkler head. The seal includes an inner tapered passageway which is compressed when tightening the sprinkler head, as well as an external taper to allow the seal to conform to the insert. In one embodiment, the seal also includes an outwardly tapered entry opening for easily receiving the sprinkler head during its installation. The fittings employ one of two different brass inserts, both of which use the unique tapered seal for receiving a sprinkler head providing strength and easy coupling.
In yet another embodiment, the same unique seal is used with an entirely plastic socket using NPSH threads for receiving tapered NPT threads of a sprinkler head. In all of the embodiments, the unique tapered seal allows easy installation utilizing relatively low torque to prevent damage to the sprinkler head and eliminates use of pipe dope or other thread sealant material. The seal provides a watertight seal between a sprinkler head and receiving socket which allows easy installation of a sprinkler head and facilitates proper alignment.
These and other features, objects and advantages of the present invention will become apparent upon reading the following description thereof together with reference to the accompanying drawings.
Referring initially to
In the embodiment of
The low torque fitting 10 further includes a rubber O-ring 50 which fits within an inwardly projecting annular O-ring receiving groove 44 of the brass insert 20 and provides a seal between the brass insert 20 and the inner cylindrical wall 35 (
The fitting 10 includes a uniquely shaped tapered seal 60 which, as best seen in
The brass insert is shown in detail in
The sprinkler head 12 is threaded into fitting 10 after the input end 30 of fitting 16 has been bonded to supply line 14. As the head 12 is installed, the seal 60 deforms somewhat, as seen in
The sprinkler head is installed in fitting 10 without the use of any sealant, which is unnecessary. The sprinkler head 12 is first threadably inserted by hand until contact with gasket seal 60 is felt. Next, using a sprinkler head wrench, the sprinkler head 12 is rotated clockwise (to tighten) a minimum of ¼ turn (90°). In order to properly align the sprinkler head for a desired spray pattern or to align horizontally, or with other heads in some installations, the seal 60 allows the sprinkler head to be further rotated up to 360° or one full turn. Thus, the geometry of seal 60 allows the sprinkler head to be properly aligned without damage to either the sprinkler head or the receiving fitting 10, while at the same time providing a watertight seal using a relatively low torque for installation. If necessary, during the lifetime of an installation it becomes necessary to replace the seal 60 it can removed and replaced with a new seal.
The steps of manufacturing the fitting 10 include (1) placing O-ring 50 in groove 44 of brass insert 20; (2) positioning insert 20 in a mold concentric with the mold walls defining the CPVC fitting 16; (3) over-molding the brass insert 20 and O-ring 50 with CPVC or other suitable polymeric material; (4) removing the fitting 16 with the sealed brass insert from the mold; and (5) inserting the annular seal 60 into the fitting 10 with surface 62 abutting annular surface 22 of the brass insert 20 in the CPVC fitting 16.
Turning now to
The cylindrical collar 175 of insert 170 provides backing reinforcement for the polymeric threads 182 and, therefore, strengthens the fitting 116. In this embodiment, the seating surface 62 of the seal (
In a third embodiment of the invention shown in
CPVC body 216 has a cylindrical input end 230 with a wall thickness of about 0.22 inches which is sealed to a supply conduit 14 (
In each of the three embodiments, the same seal 60 is employed and its multiple tapered configuration is critical to the success of all three embodiments in providing a low torque, leak-proof connection between the sprinkler head and the socket defined by the receiving fittings 16, 116, and 216. Critical elements of the seal geometry include the conical wall 63 in the center of the seal, the inwardly tapered outer edge 64 of the seal, and the annular seat 68 with tapered inlet transition wall 69 allowing the sprinkler head to be easily inserted and compress the seal 60 without damage to the seal and without interfering with the flow of water through the center aperture 61 of the seal. The material employed for seal 60 is an EPDM material having a durometer hardness of from 65 to 80, and preferably 70, to provide the desired sealing function and maintain sprinkler head position. This connection style fitting can also be incorporated in other various fitting styles, such as 90° elbows, T's and crosses, which accept direct connection of fire sprinkler heads.
It will become apparent to those skilled in the art that various modifications to the preferred embodiments of the invention as described herein can be made without departing from the spirit or scope of the invention as defined by the appended claims.
This application claims priority under 35 U.S.C. § 119(e) and the benefit of U.S. Provisional Application No. 62/378,338 entitled Low TORQUE SPRINKLER FITTING AND METHOD OF MANUFACTURE, filed on Aug. 25, 2016, by Eldon Douglas Jackson, the entire disclosure of which is incorporated herein by reference.
Number | Date | Country | |
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62378338 | Aug 2016 | US |