Valves and valve actuation – Reciprocating valve – Particular head and seat cooperation
Patent
1997-04-15
1998-04-14
Lee, Kevin
Valves and valve actuation
Reciprocating valve
Particular head and seat cooperation
251318, F16K 132
Patent
active
057383375
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a poppet damper for controlling gas flow, the poppet damper being disposed in a duct for conveying exhaust gas such as hot exhaust gas discharged from, for example, a general boiler or incinerator, and, more paticularly, to such a poppet damper with improved sealing.
BACKGROUND ART
A conventional poppet damper in an exhaust gas duct is illustrated in FIG. 4. In this poppet damper, an openable and closable poppet plate p of a poppet damper P is placed on a damper seat d disposed at a gas flow control portion in an exhaust gas duct D. It controls gas flow by an opening-and-closing operation of the poppet plate p by a driving device M via a damper shaft S.
In the aforementioned conventional poppet damper P, however, only one plate is used for the poppet plate p, which results in the necessity of using highly-sophisticated manufacturing and mounting adjustment techniques to improve sealing, in higher machining costs, etc.
In particular, when hot exhaust gas flows, the heat of the hot exhaust gas deforms the poppet plate p, the damper shaft S, the damper seat d, the duct casing D, etc., which results in inadequate sealing.
Accordingly, an object of the present invention is to overcome the aforementioned conventional problems by providing a poppet damper in an exhaust gas duct allowing easy sealing surface machining for providing a sealing surface and providing excellent sealing despite deformation caused by heat.
DISCLOSURE OF THE INVENTION
To this end, according to the present invention, there is provided a poppet damper including a damper seat, disposed in a duct casing; a poppet plate for controlling exhaust gas flow by adjustment of the gap between the poppet plate and the damper seat; and driving means for reciprocatingly driving the poppet plate, wherein a seal plate is mounted on the poppet plate, which seal plate is separated by a gap of predetermined size from the poppet plate, with the seal plate placed in contact with the damper seat, when the damper is closed. The aforementioned seal plate is preferably 0.3 to 1.0 mm thick. The gap of predetermined size between the aforementioned poppet plate and the aforementioned seal plate is preferably formed by interposing a spacer 0.5 to 2.0 mm thick therebetween .
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 illustrates a poppet damper of an embodiment of the present invention;
FIG. 2 is an enlarged view of a critical portion of a poppet damper of an embodiment of the present invention;
FIG. 3 is a schematic view of a construction of an incineration facility exhaust gas treatment system with a poppet damper of the present invention installed therein; and
FIG. 4 is a schematic view of a construction of a conventional poppet damper.
BEST MODE FOR CARRYING OUT THE INVENTION
FIGS. 1 and 2 each illustrate an embodiment of the present invention. A cylindrical damper seat 2, which forms an opening 1.2 meters in diameter, is provided in a steel-plate duct casing 1.
Reference numeral 3 denotes a poppet plate of a mild steel which is 1.3 meters in diameter and 4.5 mm thick. The poppet plate has attached thereto a 0.5 mm thick seal plate 5 of a stainless steel by a 1 mm thick spacer 4.
The aforementioned poppet plate 3 is driven in the directions indicated by arrow A by an air cylinder 7 via a damper shaft 6 to adjust the size of the gap between the aforementioned seal plate 5 and the aforementioned damper seat 2, whereby exhaust gas flow is controlled.
Although when the damper is closed, the aforementioned seal plate 5 is in contact with the aforementioned damper seat 2, it is necessary to take into account deformation of the poppet plate 3, the seal plate 5, etc., when hot exhaust gas flows. In this embodiment, the pressure difference between the upper and the lower flow at the poppet plate 3 and the seal plate 5 is 1.47 kPa (at a maximum temperatuxe of 190.degree. C.). Accordingly, at initial setting, the position of the poppet plate 3 is adjusted so that the damper seat 2 and the seal plate 5 are separated by
REFERENCES:
patent: 3951130 (1976-04-01), Lowe
patent: 4103708 (1978-08-01), Huntington
patent: 4274516 (1981-06-01), Barley
patent: 4345623 (1982-08-01), Krull et al.
patent: 4354528 (1982-10-01), McAndrew
patent: 4360370 (1982-11-01), McAndrew
patent: 4523931 (1985-06-01), Miller et al.
ABB Flakt AB
Lee Kevin
LandOfFree
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