US2276830A - Safety diaphragm - Google Patents

Description

March 17, 1942. J. H. DORAN 2,276,830

SAFETY DIAPHRAGM Filed Sept. 11, 1940 l7 l4 l5 l8 Inventor: John H. Doran,

y His Attorney.

Patented Mar. 17, 1942 SAFETY DIAPHRAGM John H. Doran, Scotia, N. Y., assignor to General Electric Company, a corporation of New York Application September 11; 1940, Serial No. 356,279

1 Claim.

The present invention relates to safety diaphragms for elastic fluid turbine arrangements. More specifically, the invention relates to arrangements including a diaphragm and a cutting edge associated therewith for cutting open the diaphragm upon the occurrence of a predetermined high pressure in the exhaust end of the turbine. In arrangements in which the diaphragm is completely out it is forced into the power plant room and thereby may cause damage to apparatus with which it may come into contact.

One object of my invention is to provide an improved safety diaphragm arrangement whereby the above danger is substantially eliminated. Another object of my invention is to provide an improved safety diaphragm arrangement in elastic fluid turbines whereby excessive pressures in the exhaust and the inlet portion thereof are eliminated.

For a consideration of what I believe to be novel and my invention, attention is directed to the following description and the claim appended thereto in connection with the accompanying drawing.

In the drawing, Fig. 1 illustrates an elastic fluid turbine arrangement embodying my invention; Fig. 2 is a top view of a safety diaphragm shown in Fig. 1; and Fig. 3 is a section along line 33 of Fig. 2.

The arrangement shown in the drawing comprises a high pressure elastic fluid turbine It) having an exhaust end connected by a crossover conduit H to the inlet 12 of a double flow low pressure turbine I3. halves i4, i5 exhausting into an exhaust casing or hood 16. The exhaust hood and the crossover conduit are fabricated and the inner walls of the cross-over conduit are formed by the exhaust hood IS. The turbine rotor is supported on bearings II, it secured to and held on the exhaust hood [3. An arrangement of this kind is more fully disclosed in the patent to O. Junggren, No. 2,102,416, issued December 14, 1937, and assigned to the same assignee as the present applioation. In order to prevent the setting up of excessive pressure in the exhaust casing [6 the latter is provided'with a safety or blow-out diaphragm l9 which is cut open upon the occurrence of a predetermined pressure in the exhaust hood to permit exhaust fluid to discharge directly into the atmosphere or other point of low pressure.

In accordance with my invention a similar safety or blow-out diaphragm arrangement 20 is provided with regard to the cross-over conduit The latter has two H. The safety diaphragm arrangements I9, 20 are substantially alike and as shown in Figs. 2 and 3 each safety diaphragm arrangement comprises a diaphragm 2| held between a grid 22 and a ring 23 secured together and fastenedto a I flanged opening 24 by means of a plurality of bolts 25. A cutting member 26 is fused to the ring 23 and has a cutting edge closely spaced with the diaphragm 21. The purpose of the grid 22 is to support the diaphragm during low pressure conditions existing inside the turbine. The pressure in the exhaust hood during normal operating condition is substantially below that of the atmosphere and the pressure in the crossover conduit is below that of the atmosphere during starting operation. If duringoperation the pressure inside the exhaust hood or the crossover conduit rises a predetermined value above atmosphere, the corresponding diaphragm 2| is forced away from the supporting grid toward the edge of the cutting member 26 whereby the diaphragm is cut open. In order to retain the central diaphragm portion cut away from the outer or rim portion, means are provided in accordance with my invention whereby the central diaphragm portion is supported on the ring 23. In the present example a cross-bar 21 extending diametrically across the diaphragm is secured to the ring 23 by bolts 28. The bar 21 is formed with a central opening 29. A pin or like member 30 is secured to the central portion of the diaphragm 2| and projects freely through the opening 29. An outer portion of the pin 30 is provided with a cotter pin 3|. If now the diaphragm is cut open during operation, the central or cut away portion secured to the pin 30 is retained on the cross bar 2'1, that is, it can no longer be thrown out into the open power plant room. The pin 38, as will benotic-ed, forms a clearance with the opening 29 in the cross-bar 21, thereby preventing interference with the free movement of the diaphragm 2! during operation.

Having described the method of operation of my invention, together with the apparatus which I now consider to represent the best embodiment thereof, I desire to have it understood that the apparatus shown is only illustrative and that the invention may be carried out by other means What I claim as new and desire to secure by Letters Patent of the United States, is:

A safety diaphragm arrangement for protecting turbine plants against excess fluid pressure comprising a grid, a ring, a diaphragm securely held between the grid and the ring and a cutting member secured to the ring with a cutting edge in proximity to the diaphragm, and means associated with the ring for retaining a central portion of the diaphragm after it has been cut away during operation, said means comprising a crossbar extending diametrically across and spaced from the diaphragm and bolted to the ring external of a chamber to be protected and a pin secured to the central portion only of the diaphragm and freely projecting through an opening in the cross-bar, the central portion of the diaphragm to which the pin is fastened being of relatively small size and considerably spaced from the cutting member so that the pin does not materially affect the flexing of the diaphragm.

JOHN H. DORAN.

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