| 摘要 |
<p>A shut-off device with an annular sealing seat (6) composed of annular metallic membranes (9, 10) having approximately identical surfaces and joined to each other on their outside diameter by a weld seam (18) and connected on their inside diameter in a tightly sealed manner to the ring (16) by weld seams (19, 20). The two membranes (9, 10) and the ring (16) together form a pressure chamber (11) in which pressure Ps is effective and which is connected via a bore (17) to the interior of housing (7) in which pressure Pb prevails. Pressure chamber (11) is also connected via a bore (12) and pipe (13) to the external shut-off valve (8). When shut-off device (1) is completely unpressurized, membrane (10) contacts shut-off element (2) at least at least on an interrupted circular line. Operating pressure Pb prevails inside pipes (3). This operating pressure should be reliably sealed off from the rest of the shut-off device (1) in each operating phase by the flexible sealing seat (6), the rigid seat (5) and and the shut-Off element (1). Seal gas pressure Pg is effective inside the rest of the housing (7) and must be higher than operating pressure Pb. Pressure Ps prevails inside pressure space (11) inside membrane system (9, 10) and is equal to pressure Pg when the shut-off element (1) is at rest. the pressure differential of Pg and Pb on the annular surface with the outside diameter, the middle seal diameter (22) and the inside diameter of the membrane (9) serves to deform the membranes (9, 10) toward the shut-off element (1), thus compressing the sealing surfaces. Pressure compensation prevails on all other surfaces, especially on those of the membrane (10). In order to displace the shut-off element (1), the compression of the sealing surfaces must be reduced to a minimum. This is achieved by opening the external shut-off valve (8). Since the cross-section of bore (17) is considerably smaller than that of bore (12), pressure Ps decreases almost to zero.</p> |
