| 摘要 |
<p>Case 04-4229-U.S. APPLICATION OF NORMAN F. GREEN NON-SYMMETRICAL OVERLOAD PROTECTION DEVICE FOR DIFFERENTIAL PRESSURE TRANSMITTER A differential pressure to electrical signal transmitter has a pair of barrier diaphragms and a central control diaphragm located between the barrier diaphragms. A first outer chamber on the outside of one barrier diaphragm is pressurized with a first input fluid while a second outer chamber on the outside of the other barrier diaphragm is pressurized with a second input fluid. A first inner chamber between an inside surface of one of the barrier diaphragms and one side of the control diaphragm is filled by a first substantially incompressible fill liquid. A second inner chamber between an inside surface of the other barrier diaphragm and the other side of the control diaphragm is filled with a second incompressible fill fluid. The fluid pressure of the two fill fluids are conducted by corresponding fluid filled channels to respective sides of a displacement sensing element to displace the element to produce electrical signal output signals which are dependent upon the difference in pressures of the first and second fill fluids and, hence, upon the pressures of the first and second input fluids. The control diaphragm is biased into a predetermined position by spring loaded spacers located on corresponding sides of the control diaphragm in the first and second inner chambers respectively. The spacers have fluid passage holes to permit the fill fluids to reach the control diaphragm. A first spacer is concentric with the first inner chamber which is smaller in diameter than the second inner chamber whereby the second spacer which is concentric with the second inner chamber overlies the peripheral edge of the first inner chamber to produce a differential input fluid pressure overload response correlated to the non-symmetrical ratio of the directional strength of the displacement sensing element.</p> |
