Steam valve

Application filed September 30,1929, Serial

My invention relates to steam valves, and more particularly to steam valves which may be loaded on either side and in which the. stop or closing member is balanced in 5 whichever direction the steam flows. Such valves are, for instance, used in’ plants for cutting off individual steam boilers from a common steam main to which are connected a plurality of steam boilers. If such valves 1q are computed according to the principles applied to low pressures, dimensions for the diameter of the valve stem would result' with the materials at present available which would about correspond with the diameter of 15 the stop member itself. The problem facing the designer is thus to relieve the valve stem of the pressure acting upon it.

The plug of the valve according to my invention is so designed that when the valve 20 is closed the plug permits the passage of a small quantity of^! steam for the purpose of increasing the closing presslire or facilitating the opening movement. This may, for instance, be attained by providing the plug 25 with bores or passages through which a communication is established between the spaces above and below the plug. This communication is preferably interrupted by an auxiliary valve with a spherical contact surface 80 which is forced down on its seat by a spring. The plug is provided with two seating faces, one being formed on the plug body and the other on an elastic plate or disk rigidly connected with the plug. If a high pressure acts 85 on this elastic disk from underneath, this disk is able to rise slightly off its seat and to permit the passage or the steam.

An embodiment of my invention is illustrated in longitudinal section in the drawing 40 affixed to my specification.

In this drawing, 1 is a valve chest through which the steam flows by way of a duct portion 2 to the duct portion 3, or vice versa from the duct 3 to the duct 2. The flow of 45 steam is controlled by means of a doubleseated plug 4 which is forced down on its seat by means of the valve stem 5. Assuming that the normal steam flow is from the duct 2 to the duct 3, and that the valve is closed, 69 a high pressure acts on the underside of

No. 396,181, and in Germany October 2, 1928.

valve plug 4 which pressure is transmitted to the valve stem 5. To ensure tightness of the valve in spite of the high pressure to which it is exposed the valve stem would have to have a large diameter in order to _β3give it the necessary mechanical strength to permit the exertion and maintenance of a sufficiently high closing or sealing pressure. The object of my invention is to make the valve stem of small diameter and to let the qq steam itself on the higher pressure side supply the major portion of the closing pressure. For this purpose valve plug 4 is provided with the bores 6 and 7 which put the space underneath plug 4 in communication with ₆₅the space 8 above the plug. This communication is controlled by an auxiliary valve 9 which has a spherical seating surface and is forced down, upon its stationary seat within the plug 4 by means of a spring 10. If the y₀pressure underneath plug 4 is very much greater than on the other side, auxiliary valve 9 is slightly forced off its seat and a small quantity of steam passes into chamber 8 through the bores 6 and 7 until the same 75 pressure is set up in chamber 8 which prevails in duct 2. As soon as this state of balance has been attained plug 4 is relieved of its load from below, ana only a relatively small force need be exerted through valve go spindle 5 to provide the necessary closing pressure to keep the valve tight. When the valve is opened with the assumed flow direction from 2 to 3, the spindle on being raised lessens first the pressure upon spring 35 10 and then lifts valve 9 and thereby establishes a free communication between the underside of plug 4 and chamber 8, so that now the spindle only has to transmit the power necessary to overcome frictional re- 90 sistances in lifting plug 4 when spindle collar 12 abuts against cap hut 14 on further raising of the spindle.

If the steam flows in the opposite direction, from the duct 3 to the duct 2, a small 95 quantity of steam can pass through passages 16 between the plug and its guide sleeve 15 into the chamber 8 because the upper seat of plug 4 consists of a resilient plate 11 which yields as long as' le pressure below the plate ioc

1,870,293 in clearances 16 is greater than above it. whereby the fluid pressure established in said As soon as the same pressure has been set chamber assists the spindle m holding the up in the chamber 8 as in duct 3, the plug plug on its seat, and means operated by said is exposed at the top to the high pressure spindle for lifting said spring controlled existing in duct 3 which assists materially valve from its seat when the spindle is raised the closing pressure exerted by spindle 5. to unseat the valve plug. .

If it is desired to open the valve, spindle In testimony whereof I affix my signature. 5 upon being raised, raises first the spherical HAN8 ΜΙΗΙ/ΚΚ.

valve 9 until the collar 12 comes in contact with the lower face 13 of the cap nut 14 in which valve spindle 5 is journalled. In this way communication is set up first between chamber 8 and duct 2, and the steam in chamber 8 escapes into duct 2 and thereby unloads the top of the valve and lessens the resistance to the opening movement of the valve plug.

Various changes may be made in the structure described without departing from the spirit of my invention.