Valves and valve actuation – Pivoted valves
Patent
1991-03-26
1992-06-09
Rivell, John
Valves and valve actuation
Pivoted valves
251356, 13762544, 137875, F16K 120
Patent
active
051200210
DESCRIPTION:
BRIEF SUMMARY
This invention relates to improvements in or relating to isolators, i.e. isolating valves, especially diverter and flap isolators. The invention is particularly concerned with the flap and blade construction of small such isolators.
Diverter and flap isolators are commonly used for gas turbine/waste heat recovery systems and other applications where high temperatures are involved. The isolators are fitted with thermal insulation to minimise the radiative and convective heat losses to the isolated space. The fitting of thermal insulation can cause, however, uneven temperature distributions throughout the blade structure which can lead to distortions and thus impair the sealing efficiency.
For large isolators this problem can be overcome by having a separate load bearing flap arm system to which separate blades are attached, one in the case of flap isolators, and two in the case of diverter isolators. As will be described in more detail subsequently with reference to the diverter isolator shown in FIG. 1 of the drawings, the attachment of the blade(s) to the flap arm assembly is carried out in such a way that differential movements are possible between the blade and flap arm assembly. For small flap and diverter isolators (typically up to 2m square) this solution :s unnecessary as the differential movements are small. Further, because of smaller size it is difficult to design such a system in a suitably compact manner.
The present invention aims to overcome or at least mitigate the disadvantages of the known isolator systems.
The present invention provides an isolator wherein blade frame members thereof are used as load bearing members for transmitting the blade loading to an operating shaft.
There is suitably used a combined blade and flap arm assembly in which the side members of the blade frame are extended to attach to the shaft, acting as the load bearing members of the flap system. The edges of the blade frame are completed on the other two sides parallel to the shaft by two lateral channel members. Optionally an additional angle frame is welded to the blade plate to enable a double sealing system to be applied to one or both of the outlets. Flexible metallic seals are fitted to the periphery of these frames to provide the necessary closures.
Preferably insulation is provided on one side only of a blade plate, and the blade plate is attached to a cross-sectionally generally channel-shaped blade frame.
The blade plate is most preferably welded to the blade frame, either directly or through at least one strip.
Alternatively the blade frame may be provided with at least one flat strip around the inside boundary of the frame, the blade plate being bolted to the flat strip(s).
The insulation can be suitably retained between the blade plate and cladding, or alternatively the insulation can be retained between two blade plates.
A single or double seal is preferably provided at each side of the channel-shaped blade frame.
Where no insulation is required then the blade plate can be welded into the blade frame as no significant temperature differential exists between the blade frame and the blade plate.
In the case that insulation is required it is necessary to employ a different construction. Suitably the blade frame is provided with two flat strips around the inside of the frame, drilled to enable the blade plate to be bolted to it The outer strip is welded to the frame after bolting the blade in place. The holes in the blade plate are sufficiently large to take up the anticipated amount of differential expansion. The blade plate is attached to the blade frame using bolts, nuts, flat washers. On assembly the bolts are fully tightened, then slackened off a predetermined amount to ensure that the blade plate can differentially expand with respect to the blade frame, the nuts being finally tacked to the bolt to prevent slackening.
In this construction the insulation need only be on one side of the blade only, because the amount of differential expansion which can be accommodated is not limited by the maximum indu
REFERENCES:
patent: 3035810 (1962-05-01), Lowe et al.
patent: 3592221 (1971-07-01), Worley et al.
patent: 3698429 (1972-10-01), Lowe et al.
patent: 4207864 (1980-06-01), Fischer et al.
patent: 4294283 (1981-10-01), Scharres
patent: 4531361 (1982-09-01), Worley
patent: 4552181 (1985-11-01), Hawkins
patent: 4821507 (1989-04-01), Bachmann et al.
patent: 4821771 (1989-04-01), Maxwell
Hearnden Trevor H.
Squirrell Anton F.
Grovag Grossventiltechnik AG
Rivell John
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