Fluid handling – Line condition change responsive valves – With separate connected fluid reactor surface
Patent
1996-09-10
1998-01-13
Ferensic, Denise L.
Fluid handling
Line condition change responsive valves
With separate connected fluid reactor surface
62225, 236 92B, 137495, F16K 3112
Patent
active
057068534
DESCRIPTION:
BRIEF SUMMARY
The invention relates to a valve, especially a thermostatic expansion valve, having a housing carrying a valve seat, having a closure member which is movable by the force of a working element against the force of a setpoint spring, and having a setpoint adjusting device housed in a lateral connecting tube, which adjusting device engages by means of a contact face with a sloping face of an axially guided plate supporting the setpoint spring and has an adjusting screw for displacing the contact face with a component acting radially with respect to the plate axis.
Such valves are known, for example, from DE-PS 964 241 or FIG. 7 of U.S. Pat. No. 5,186,207. The control by means of a sloping face of the plate supporting the setpoint spring has the advantage that a compact type of construction is produced. Manufacture requires a considerable degree of machining, however, for example, in the cutting of a thread in the connecting tube receiving the setpoint adjusting device.
In FIGS. 1 and 4 of U.S. Pat. No. 5,186,207, inlet and outlet connecting tubes are formed by portions of tube inserted in the remainder of the housing. For the purpose of adjustment, a pressure-applying piece bears by means of a sloping contact face on the sloping face of the plate supporting the setpoint spring, and is secured in its position by indentations in the tube wall of the outlet connecting tube. Subsequent adjustment of the set point is not possible in this case, however.
The invention is based on the problem of providing a valve of the kind mentioned at the outset, in which machining in the area of the setpoint adjusting device is reduced or completely avoided.
This problem is solved according to the invention in that the adjustment device comprises a pressure-applying piece which carries the contact face, is secured against rotation and has a threaded bore, and the adjusting screw engages with its shank in the threaded bore and is secured against displacement by bearing against the connecting tube.
By separating the contact face and the adjusting screw the thread engagement can be moved from the housing to the pressure-applying piece. Means for preventing rotation of the pressure-applying piece and axial displacement of the adjusting screw are all that is required on the housing. This can be achieved without machining the housing. A further advantage consists in that the sloping contact face does not rotate with the adjusting screw. The contact face can therefore have a large area lying against the sloping face of the plate supporting the setpoint spring.
It is especially favourable for the connecting tube to be in the form of a shaped sheet metal part. The sheet metal can be easily shaped to fulfil the remaining functions (safeguarding against rotation, stop function).
It is also favourable for the connecting tube to be formed by a substantially cylindrical tube which is attached to a base housing. The tube can be pre-assembled together with the adjusting device, and subsequently joined to the base housing.
An especially simple means guarding against rotation is provided when the pressure-applying piece has on its circumference at least one longitudinal groove in which an indentation of the connecting tube wall engages.
In a further embodiment, a sealing ring surrounding the head of the adjusting screw is provided, the sealing ring being secured in position on one side by a flange on the head and on the other side by an annular limiting disc positioned against the head and held in place by an indentation in the connecting tube wall. The indentation can be identical to that for safeguarding against rotation. The sealing ring held fixedly in this manner between the flange and the annular disc effects a good seal with respect to the medium in the housing, especially a refrigerant.
Moreover, it is advisable for a bushing to be fitted at the outer end of the connecting tube, against which the head of the adjusting screw bears. This bushing therefore forms a stop member which secures the adjusting screw against axial displacement.
The b
REFERENCES:
patent: 2182718 (1939-12-01), Anderson et al.
patent: 2258295 (1941-10-01), Merz
patent: 5148978 (1992-09-01), Stapelbroek
patent: 5186207 (1993-02-01), Kaneko
R.o slashed.nnow Allan
Rasmussen Jens Erik
Vestergaard Anders
Danfoss A/S
Farid Ramyar M.
Ferensic Denise L.
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