Issue: 6/01
It has become the formula for financial viability for a company to increase quality while reducing material and labor costs. It is, however, a difficult proposal since every company tries to do the best with the least, so how can they possibly do better?
The answer is of course to find a new, and theoretically better, way of doing things. But when that question comes to something as common as joining pipes, we are frequently so in tune with the traditional way of doing things that it becomes difficult to imagine any other way. Fortunately, there are inventors out there with nothing on their mind other than new ways of doing everything, including joining pipes.
New Pipe Joining Method
Inventor James David DiRocco of Delmar, DE, is among those creative inventors making new inroads in the field of mechanical piping technology. DiRocco received U.S. Patent no. 6,149,206 on November 21, 2000, for his latest development titled, "Fluid Distribution Apparatus and Method." The invention, now assigned to Dresser Industries, Inc., in Dallas, TX, is a sort of quick connect device for pipes that utilizes very standard industrial components.Although the patent doesn't make an issue of it, the invention is aimed at large diameter piping typically joined with welded or soldered flanges that are ultimately bolted together with a gasket. Ostensibly, the design could be applied to small diameter pipes, but with the idea of cost savings through reduced materials and labor, it almost assuredly will only be applicable to large diameters as a flange replacement technique.
The idea is fairly simple. Pipes used in this system have a series of two beads raised near the end of the pipe, and connections have a bore with an internal shoulder. A packing seal is placed between the two beads, and the pipe end is inserted into the bore until it rests on the shoulder. Finally, a mechanical fastener is inserted through the connector to hold the pipe in place.
The patent states that the beads can be formed by any applicable manufacturing process, and even goes so far as to say they can be formed on a lathe. However, in the name of cost savings, it seems that for malleable materials, the beads could be swaged directly onto the end of the pipe or cast on for non-malleable materials. Bead spacing is simply a function of the diameter of standard seals that will be great enough in diameter to provide adequate sealing with the internal bore of the connectors.
Fastening the pipe to the connectors is accomplished using either standard commercial hardware, or at the very least, hardware manufactured specifically for the purpose that is based on standard hardware designs. The patent spells out at least three specific types of hardware that can be used to connect the components, including essentially an external snap-ring, and internal snap-ring and pins. Additionally, there is no reason to believe that bolts couldn't be used in the same type of application as the pins in the event that the installer wanted to be more certain of a positive lock on the fasteners.
Advantages
The invention offers the distinct advantages that it is far less labor intensive to install and therefore faster to install, and it doesn't require specialized operators such as certified AWS pipe welders to operate in the field. Moreover, snap-rings or pins, or even only two bolts, are much faster to install than conventional bolting, and it doesn't require the operator to have a calibrated torque wrench on hand. Finally, there are some advantages over bolted flanges, where the bolted connection must be inspected as part of a regular preventive maintenance schedule. There are inherent problems with the inspection of installed bolts in the field dealing with the plastic deformation of the fastener, which, although beyond what we have room to describe here, are very difficult issues for inspection and compliance with government standards.Although Dresser Industries specializes in equipment for oilfield industries, this system could be equally applicable to any industrial, residential, commercial or municipal fluid distribution or collection system. Regardless of whether the pipes are plastic, cast iron soil pipe, malleable iron or even potentially concrete, the design seems to have suitability to almost any large diameter piping application.
