Gas and liquid contact apparatus – Fluid distribution – Valved
Reexamination Certificate
1999-04-27
2001-02-13
Bushey, C. Scott (Department: 1724)
Gas and liquid contact apparatus
Fluid distribution
Valved
C261S079200, C261SDIG001
Reexamination Certificate
active
06186481
ABSTRACT:
SUMMARY OF THE INVENTION
This invention relates generally to static mixing of fluids, and more particularly to an apparatus for mixing streams of water and steam and delivering a stream of heated water.
In many industrial operations, especially in chemical processes, plant steam provides a convenient source of heat, and can be mixed with water, to provide instant hot water. Conventional steam-water mixing devices, however, are subject to several problems.
One problem with conventional steam-water mixing devices is due to the rapid collapse of steam bubbles as the steam condenses upon contact with the water. The rapid collapse of steam bubbles sets up vibrations in the mixing device and in associated plumbing, producing a large amount of noise.
Another problem is that failure of the water supply to a conventional mixing device can cause it to deliver steam at its outlet unless elaborate precautions are taken to make the mixing device fail-safe.
The principal object of this invention is to provide a simple and reliable steam-water mixing device that is much quieter in operation that previously available steam-water mixers. Still another object of the invention is to provide a simple steam-water mixing device that reliably avoids dangerous maloperation in the event of a water supply failure.
Briefly, the invention addresses the noise problem by guiding the incoming water and steam into coaxial vortices inside and outside of a tube, respectively. The vortices come together just beyond an open end of the tube, and mix to produce a stream of heated water. Regulation and fail-safe operation are achieved by using the tube itself as a component of a valve. The tube is moved axially by a temperature-responsive mechanical actuator, and cooperates with a deflecting shoulder in a housing to regulate the flow of steam. The movement of the tube relative to the actuator not only regulates the temperature of the water, but also shuts off the flow of steam in the event of a failure of the water supply.
The steam and water mixing apparatus in accordance with the invention has, as one of its components, a tube extending along an axis and having an axial opening at one end. Water is directed, preferably by a first set of vanes, into the interior of the tube, to establish a first vortex of water circulating about the axis, both within the tube and beyond the axial opening. Steam is directed, preferably by a second set of vanes, in a second vortex surrounding the tube, circulating about the axis and extending beyond the end of the tube. The vortices are directed into contact with each other, preferably by a deflecting surface which reduces the radius of the steam vortex, and by an expansion space causing the water to be directed outward, so that the water and steam mix together to produce a stream of heated water.
Several other features are present in a preferred embodiment of the invention. One such feature is that the water and steam are directed into counter-rotating vortices. Other preferred features include the following.
The flow of steam is regulated in response to the temperature of the exiting heated water stream to maintain the heated water at a substantially constant temperature, and the temperature-responsive regulating mechanism also shuts off the flow of steam when the rate of flow of water falls below a predetermined minimum level. The tube and the deflecting surface are relatively movable in the direction of the axis to vary the cross-section of the steam flow passage, so that the tube and surface together serve as a steam valve. The flow of steam is controlled by a temperature-responsive actuator for effecting relative axial movement of the tube and the deflector surface in a direction to reduce the cross section of the flow passage as the temperature of the heated water increases.
The actuator is preferably a mechanical actuator comprising a body and a stem which projects from the body as the temperature of the heated water increases. The actuator body is connected to the tube through a sleeve which extends along the axis into the tube through the axial opening. The stem of the actuator bears against a rod which extends, along the axis, through the sleeve and in turn bears against a surface which is held in fixed relationship to the tubular enclosure. Thus, the actuator moves the tube axially relative to the deflector in a direction to decrease the cross-sectional area of the annular opening as the temperature of said heated water in the exiting stream increases. An adjusting screw, threaded into the tubular enclosure and extending along the axis, has an end providing the surface against which said rod bears.
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Bushey C. Scott
Howson and Howson
Therm-Omega-Tech, Inc.
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