Patent Application
20130292596
My invention relates to the field of automatic control and more specificly to Control Valves used in the regulation of flow, pressure, or temperature, for example, as is common in the process industry.
A more refined application can be found in the climate control of buildings handling chilled water or steam, for example. Such valves tend to be small, need to be less costly, and be reliable.
Globe style control valves have been used in the past. However, they tend to be more bulky, are more costly, and offer only restricted flow capacity. Ball valves are another typical alternative comprising a pieced ball, squeezed between a pair of Teflon seals and rotated by a shaft. While such valves have more than ample flow capacity, they tend to be hard to operate due to the great friction exerted by the seals, when one attempts to open such valves. This necessitates the use of strong, and hence more costly, operating devices. This friction also creates undesirable dead-band or hysteresis, a major detriment for automatic and stable control.
The current invention overcomes all such objections in that it has ample flow capacity, in excess of what is offered in globe valves; it is of compact size and consists of few parts, all major cost savings. Finally, with exception of a low stem seal friction, there is virtually no operating friction, offering the use of much smaller (and hence less costly) operating devices. Such absence of objectionable operating friction also allows for a very smooth and stable control action, translatable into a much closer temperature control.
Referring to
Plug 6 has a spherical circumferential portion 10 capable of closingly engaging the intersection between the orifice 4 and said tapered ending 9, wherein the tapered ending of center section 8 assists plug 6 to center itself when approaching said orifice.
Plug 6 furthermore has a bulbous extension 11, configured to sweep by the corner of the orifice, defined as the upper part of inner circumference facing the tapered ending 9, when the plug is rotated up to 45 degrees away from the closed position. This will limit the flow passing that portion of the orifice, resulting in a more gradual opening characteristic between flow and plug travel as depicted by curve B in
The bulbous extension 11 can be omitted (see dotted line 12) whenever an alternate linear relationship, as shown in line A of
Housing 1 has a neck 13 as shown in
Neck 13 in addition, houses a guide bushing 16 having a recess 17 containing therein a shouldered portion 18 of shaft 7, to prevent the latter to be expelled by fluid forces from housing 1.
Finally, a seal 19 is retained between a recess in neck 13 and guide bushing 16, while a threaded retainer 20 keeps the guide bushing 16 in its proper location.
Plug 6 features a slotted opening 21, more clearly shown in
Having thus shown the function and features of the invention in a preferred embodiment, it should be understood that numerous changes can be made without departing from the scope of the following claims. For example: A pin might connect the plug to a round shaft instead of using a square and, a flange or a retaining ring might be employed instead the shown threaded retainer to keep the guide bushing in place. Furthermore, flange connections to a pipeline could replace the threaded ports shown in
Finally, a separate seat ring, perhaps made from a harden able metal, might be inserted at a proper location within said housing, instead of the lower cost, integral orifice being part of said housing.
