Process detection apparatus

• US 5,554,809 A
• Filed: 10/05/1994
• Issued: 09/10/1996
• Est. Priority Date: 10/08/1993
• Status: Expired due to Term

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Kobayahsi, Teruo, Fukunaga, Masao, Yamamoto, Yoshimi, Tobita, Tomoyuki, Nagasu, Akira
• Primary Examiner(s): Chilcot, Richard
• Assistant Examiner(s): AMROZOWICZ, PAUL DOUGLAS
• Application Number:
  US08/318,315
• Time in Patent Office: 706 Days
• Field of Search: 73/700, 73/716, 73/723, 73/756, 345/33, 345/38, 345/43, 345/50, 345/55, 345/117, 340/815.44, 340/815.78, 340/815.79, 324/156
• US Class Current: 73/700
• CPC Class Codes: G01L 19/0007 Fluidic connecting means
• CPC Class Codes: G01L 19/0038 being part of the housing other details about the housing G01L19/14
• CPC Class Codes: G01L 19/02 Arrangements for preventing, or for compensating for, effects of inclination or acceleration of the measuring device; Zero-setting means for aneroid barometers G01L7/14
• CPC Class Codes: G01L 19/0645 using isolation membranes, specially adapted for protection
• CPC Class Codes: G01L 19/142 Multiple part housings
• CPC Class Codes: G01L 19/146 using flexible element between the transducer and the support
• CPC Class Codes: G01L 19/148 Details about the circuit board integration, e.g. integrated with the diaphragm surface or encapsulation

Abstract

A compact pressure differential/pressure detector is a process detection apparatus for measuring a pressure, a level, a pressure differential of a process fluid. The detector is constructed of a pressure sensing block having sensors for sensing a pressure and a pressure differential, a signal processing block for processing signals from the pressure sensing block, and a terminal board block for receiving power supply from outside and transmitting signals to outside. These blocks are arranged along the same axis. Furthermore, an indicator indicating a process state is also arranged along the same axis and received in a covering case. The case is firmly attached to the pressure sensing block. The process detection apparatus permits a compact design and offers an excellent maintainability.

Claims

1. A process detection apparatus for providing data regarding process fluid as an output to an external element, the apparatus comprising:

a pressure sensing body having a sensor sensing a pressure of the process fluid;

a signal processing portion having a signal processor circuit processing a signal from the pressure sensing body; and

an indicator provided on the signal processing portion and indicating data regarding the process fluid;

wherein,

said sensor, said signal processor circuit and said indicator are arranged substantially along a common axis;

said signal processing portion and said indicator being formed in substantially cylindrical shapes respectively; and

said signal processing portion being movably mounted to said pressure sensing body for change of relative positions of said signal processing portion and said pressure sensing body.

2. The apparatus according to claim 1, wherein said signal processing portion has cable entries provided therein for routing cabling for connection of the apparatus with high level control equipment, said cable entries being variable in orientation through a change of the relative positions of said signal processing portion and said pressure sensing body.

3. The apparatus according to claim 2 wherein said indicator is movably mounted to said signal processing portion for change of a relative position thereof to said signal processing portion and said pressure sensing body so that even when the orientation of the cable entries is changed, a direction of indication of the indicator remains unchanged.

4. The apparatus according to claim 1, wherein said signal processing portion is rotatable at 90-degree pitches relative to the pressure sensing body.

5. The apparatus according to claim 1, wherein said pressure sensing body is provided with a recess in which at least a part of the signal processing portion is rotatably received.

6. The apparatus according to claim 5, wherein said signal processing portion has holes formed therethrough and threaded bars passing through the respective holes and engageable with the pressure sensing body so that the pressure sensing body and the signal processing portion are fixedly attached to each other through the threaded bars.

7. The apparatus of claim 1, wherein said signal processing portion has a cover providing sealing and said indicator is received in said cover of the signal processing portion, said indicator being held in the cover during open and close of the cover.

8. The apparatus according to claim 7, wherein said signal processing portion includes at least one board and connector terminals mounted thereon, said indicator is rotatable with respect to the cover and has terminals engageable with the terminals of the signal processing portion so that the indicator is prevented from rotating with respect to the cover with the terminals of the indicator engaged with the terminals of the signal processing portion.

9. The apparatus according to claim 8, wherein when the terminals on the board are mated with the terminals of the indicator, the terminals of earth potential are first mated with one another.

10. The apparatus according to claim 1, wherein said signal processing portion has a substantially cylindrical casing, and said signal processor circuit includes two or more circular boards which are in a shape generally conforming to a cross-sectional shape of the cylindrical casing and are connected to one another in a face-to-face manner.

11. The apparatus according to claim 3, wherein said indicator is rotatable at 90-degree pitches relative to the pressure sensing body.

12. A processing detection apparatus comprising:

a pressure sensing body having a sensor sensing a pressure of a process fluid;

a signal processing portion attached to the pressure sensing body and having a signal processor circuit processing a signal from the pressure sensing body;

an indicator provided on the signal processing portion and numerically indicating data regarding the process fluid; and

a signal output circuit transmitting the signal from the sensor to outside;

wherein said indicator is formed to indicate a first mark that represents that the data displayed by the indicator have been converted according to a predetermined function by the signal processor circuit, and said indicator indicates a second mark that represents that the data outputted by the signal output circuit have been converted according to the predetermined function prior to output.

13. The apparatus according to claim 12, wherein the predetermined function is a square-root function.

14. The process detection apparatus of claim 12 wherein said indicator includes therein a level meter made up of a set of predetermined marks, and said level meter is formed to have indicator tuned to a zero point adjustment and to light the marks of the level meter to a middle position when a zero point of the sensor is reached.