1. Field of the Invention
The present invention relates to pressure transmitters. More specifically, the present invention is directed to a pressure transmitter using a sealed pressure transmitting system including a barrier diaphragm facing a fluid being monitored.
2. Description of the Prior Art
Pressure transmitters utilizing a pressure sensor, e.g., a semiconductor chip, arranged in a sealed fill fluid system with a barrier diaphragm facing a fluid being monitored are well-known in the art, e.g., the differential pressure transmitter shown in U.S. Pat. No. 3,559,488. In order to facilitate the connection of such a pressure transmitter to a fluid being monitored the use of a remote connection between the barrier diaphragm at the fluid being monitored and the pressure sensor has used a fluid filled capillary transmitting the pressure from the barrier diaphragm to the sensor, e.g., the pressure transmitter shown in U.S. Pat. Nos. 2,906,095 and 3,999,435. However, in those differential pressure transmitters there was no provision for enabling the barrier diaphragm to be selectively positioned within a container or housing containing the fluid being monitored whereby the barrier diaphragm is located at a desired location with respect to the internal wall surface of the container containing the monitored fluid, e.g., flush with the internal wall surface. In order to provide such a capability in a limited fashion the pressure transmitter has been supplied with a barrier diaphragm located on one end of a projecting tube with a pressure transmitter and a mounting flange attached to the other and of the tube. By providing a plurality of different lengths of the tube between the attached transmitter and the flange, the corresponding location of the diaphragm in the container containing the fluid being monitored is achieved. However, such a structure has necessitated the manufacture, storage and use of a plurality of pressure transmitters with corresponding tube lengths to satisfy the various requirements of the industry for the location of the barrier in the monitored fluid. Accordingly, in order to provide a universal and adaptable pressure transmitter capable of affording an infinite number of tube lengths for selectively locating the barrier diaphragm in the fluid, it is desirable to provide a pressure transmitter having a selectively variable location of the diaphragm with respect to the mounting flange at a distanc defining the location of the barrier diaphragm in the monitored fluid.