Fluid handling – Processes – Involving pressure control
Reexamination Certificate
2000-07-19
2001-08-28
Michalsky, Gerald A. (Department: 3753)
Fluid handling
Processes
Involving pressure control
C137S360000
Reexamination Certificate
active
06279595
ABSTRACT:
I. FIELD OF INVENTION
The present invention relates to an improved flow rate valve system and valve, especially for axially-rotated valves and includes both apparatus and methods. In particular, the present invention has applicability where a freeze resistant valve is preferred.
II. BACKGROUND OF THE INVENTION
Valves have been used for many centuries in a variety of applications. As the technology has progressed, more sophisticated uses have been found for valves. For instance, various improvements have been made in methods of actuation of the valve. Some of these methods include motor driven actuation, solenoid actuation and more recently, computer controlled actuation, and so forth However, the essential flow design of valves has stayed relatively constant along four basic designs.
One type of valve used is a gate valve. It is simple in design, inexpensive, and can be used in a variety of applications. A gate valve typically contains a circular disk, known as a gate, mounted transverse to a conduit or pipe which engages a seat to block or restrict flow. A gate valve is generally known to those in the art as being poor for controlling flow other than in a fully-opened or fully-closed position. The interface between the gate and its seat generally erodes and is prone to maintenance.
Another typical valve is known as a globe valve. Those in the art know that it is good for throttling at other than fully-opened or fully-closed positions. An example is shown in U.S. Pat. No. 4,066,090 to Nakajima et al. As can be seen, the flow path is somewhat circuitous resulting in generally higher friction losses, nonlaminar flow, and may prematurely induce flow separation and/or cavitation. Thus, flow rates tend to be less than those of a fully-opened gate valve, the fluid flow path tends to wear, and the globe valve, because of its inherent construction, tends to be bulky.
A third type is a ball valve. The ball valve may offer some advantages of increased flow over the globe valve. The valve actuator connected to the ball is mounted transverse to the flow. As the valve opens, the ball is rotated and aligns a central hole in the ball to the conduit through the valve. The ball valve tends to be somewhat bulky, generally uses two seating surfaces on either side of the ball, and may be somewhat expensive to manufacture.
A fourth type of valve is known as a butterfly valve. The butterfly valve has an internal seat that is typically oriented transverse to the conduit. An external valve stem rotates typically a circular disk transverse the conduit to engage the seat to block fluid flow. A butterfly valve generally has high flow rates and low maintenance. However, it retains the typical construction of a transverse-mounted valve with a transverse valve stem. While the valve stem may be remotely actuated by motors and other devices known to those in the art, it may not be suitable for sealed installations where it might be desirable to completely encase the valve, remote actuator, and seat in a conduit for efficient installation nor is it suitable for installing in a wall structure where access to the actuator is restricted because of the transverse orientation.
An underlying quest in the various designs of valves is a balance between low friction losses, high flow rates, and throttling characteristics. Other considerations may include freeze resistance, simplicity of construction, cost of manufacturing, and perhaps other specialized uses. While there have been numerous variations of the valve types such as described above, there remains a need to provide an improved flow, low friction valve. This may be especially useful in applications where a remote actuation along a central axis is desired. Typically, these installations involve freeze resistant installations.
In addressing freeze prevention or reduction, efforts have been concentrated on a remote location of a plug of a globe valve away from ambient conditions that could lead to freezing. A typical example is seen in FIG. 7 of U.S. Pat. No. 4,532,954. By remotely locating the plug, the flow of the liquid, typically water, could be stopped a distance in a pipe or a conduit away from the freezing ambient conditions. Those in the art typically concentrated on a globe valve type seat because of the inherent difficulty of actuating a gate valve from within the conduit. In this construction, the nose portion engages a valve seat to seal any flow at a remote location from adverse ambient conditions. As is shown in that figure, the nose must engage a valve seat through the aperture that restricts the flow of water. This remote location results in a beneficial blocking of the water away from the freezing ambient conditions. However, it causes other problems. The wear surfaces may be prone to water erosion and deposits from water impurities. Also, in order to obtain a proper seal, the mechanical advantage of the screw of the valve stem may, after much use, crush the tip of the nose portion. Once the nose was crushed or deformed, it required even harder tightening of the nose which eventually lead to leading (the famous “drip drip”). Also, the inherent design of the nose portion, engaging an aperture, causes a significant pressure drop, as those with ordinary skill in the art would immediately recognize. This significant pressure drop reduces flow rates. Reduced flow rates may cause a necessarily proportional increase in the size of conduit, valve, or other devices to obtain the needed flow rates. Additionally, the use of the nose section was a modification of the globe valve type seat which required many turns to suitably seal the flow. Likewise, the valve control rod (stem) moved in the typical longitudinal direction—it was not fixed with respect to the conduit or pipe in which it was assembled. Therefore, increased wear and increased maintenance resulted from not only the rotational movement, but the longitudinal movement as it engaged those portions of the valve seat. While an increase in size of the typical valve might achieve the necessary flow rates, typically, this was not a viable option because of size, costs, and compatibility with other components of the piping system.
Thus, prior attempts to remotely seal the water flow or other liquids lead to high pressure drops, low flow rates, and maintenance. The flow rate is especially important in designing sprinkling systems. Both residential and commercial sprinkler systems require a higher flow rate than the typical gate valve or globe valve delivers for given typical size. Thus, an installation was not able to use the typical valving of a typical free resistant hydrant—instead, it required a direct connection to other piping with sophisticated valving controls. The sophisticated valving, as those with knowledge of sprinkler systems would recognize, required expensive controls, maintenance, purging during off season uses, local and national codes, and other issues.
A further complication resulted from the axially rotated valves such as the valves referenced above and others such as U.S. Pat. No. 3,848,806 to Samuelsen, et al. This actuation shows that the valve stem on such axially-rotated valves has been heretofore in the flow path. Until the present invention, on such axially-rotated valves, it may have been considered by those in the art that the valve stem was required to be placed in the flow path in order to engage remotely the nose portion to the aperture. However, the additional turbulence and volume contained by the valve stem in the flow path results in additional loss of efficiency, increased resistance and friction, and lower flow rates.
Thus, as systems have become more sophisticated, a need exists for a valve that can be remotely actuated through the internal structure of a valve away from adverse ambient conditions, and yet be inexpensive, easily installed, of the same or similar diameter to existing piping systems, and still maintain high flow rates and low pressure drops. If a system was available that would allow a high flow rate water hydrant that could be converted to a combinat
Burgess Robert K.
Lindberg William R.
Walrath David E.
Big Horn Valve, Inc.
Michalsky Gerald A.
Santangelo Law Offices P.C.
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