WO1998053288A1

WO1998053288A1 - Sensor capsule for pressure transmitter

Info

Publication number: WO1998053288A1
Application number: PCT/US1998/010160
Authority: WO
Inventors: Douglas W. Wilda; James V. Davidson
Original assignee: Honeywell Inc.
Priority date: 1997-05-23
Filing date: 1998-05-18
Publication date: 1998-11-26
Also published as: AU7687798A

Abstract

A sensor capsule for use in a pressure transmitter utilized in monitoring a continuous pressurized transmission system, and included silicon pressure sensitive die operates in response to pressure changes to initiate electrical signals in response to the pressure changes. The capsule is designed to integrate with a meter body adapted for connection to associated transmission systems by means of a so-called 'sanitary-seal' connection.

Description

SENSORCAPSULEFORPRESSURE TRANSMITTER

BACKGROUND OF THE INVENTION

1. FIELD OFTHE INVENTION

The present invention relates to continuous pressurized transmission systems. More particularly, the present invention relates to a sensor capsule adapted to be utilized with meter body construction as utilized in a pressure transmitter for providing pressure information from an associated piping system.

2. BACKGROUND ART The present invention helps to overcome some of the problems associated with prior meter bodies associated with transducer equipment manufactured by the assignee of the instant application. This was true of a flange mount solution employed to provide meter body connection. This unit was difficult to interface with an associated characterization system. The characterization system being utilized for initializing or establishing the parameters for operation of the connected meter. Accordingly, a characterization system unique only to that design was required. Also previously utilized was a remote seal element employing a custom design adapted to specific customer requirements. Such a design was costly to manufacture and provided a great degree of difficulty in providing an appropriate interface to a characterization system. A search of the background art directed to the subject matter of the present invention conducted in the U. S. Patent and Trademark Office disclosed the following U. S. Letters Patent:

3,836,183 4,896,902

4,355,828 5,058,928 4,372,587 5,366,263

4,620,731 5,401,062

4,787,654 5,437,482

A thorough review of the above-identified patents has concluded that none are believed to claim, teach, or disclose the novel combination of elements and functions set forth in the present invention.

Accordingly, it is the object of the present invention to provide an improvement in the manufacture of a sensor capsule for use in a pressure transmitter which interfaces to a variety of customer connections by utilizing a meter body as a base module including the industry standard quick disconnect "sanitary- seal" configuration. Of particular significance in the present invention is that feature relating to the utilization of an interface to a characterization system that is both simple and economical. Another feature of the present invention is its modular construction. Because of the latter only a single module need be constructed to satisfy numerous customer applications, particularly inasmuch as the associated meter body of the transmitter provides the necessary sanitary-seal type connection.

SUMMARY OF THE INVENTION

The present invention achieves the above objects and features by providing a sensor capsule useful in a meter body assembly that is readily adaptable to a number of different types of connections in transmission piping systems containing a media under pressure within the system. The sensor capsule is designed to provide a connection to an associated meter body which includes a centrally located bore running vertically through the meter body. The meter body is filled with liquid and in response to pressure applied to a diaphragm at the bottom of the meter body, from the media within the transmission system, pressure is exerted in an upward direction through the bore onto the sensor capsule. More specifically, the pressure is applied to the lower end of the sensor capsule. A silicon pressure sensitive die is mounted within the sensor surrounded by a ceramic board with printed circuitry thereon including an analog to digital converter connected to the pressure sensor. Also included is an electrically energizable programmable read-only memory. From the printed circuitry included on the ceramic board are also connections to a plurality of signal pins which extend out of the sensor capsule to provide electrical connections to the electronic housing control unit connected to the upper end of the meter body assembly, which contains the associated electronics. The signal pins are extended through a glass seal. The sensor capsule is secured in place by being attached to the meter body and by having a sensor cover attached to the sensor and meter body. BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings wherein:

FIG. 1 is an exploded view of a meter body assembly including the sensor capsule of the present invention.

FIG. 2 is a cross-sectional view of a sensor capsule in accordance with the teachings of the present invention.

FIG. 3 is a cross-sectional view of a portion of a meter body assembly, showing a sensor capsule as taught by the present invention positioned on a meter body adapted for sanitary-seal connection.

FIG. 4 is a simplified schematic circuit diagram of a sensor capsule in accordance with the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring first to FIG. 1, a meter body assembly 21 is shown utilizing a sensor capsule 12 in accordance with the present invention. The assembly 21 includes meter body 11, sensor capsule 12, "O" ring 13, sensor cover 14, a housing interface 15, and the electronics control circuitry housing 16 with an end cap housing 17 shown removed. The assembly can be utilized with a process adapter flange 18, as shown. As seen in FIG. 2, the sensor capsule of the present invention is shown in cross section is cylindrical in form constructed basically of metal including therein a pressure sensor die of silicon construction. Pressure sensor die 12B is secured to a ceramic board 12K by means of a stress isolation die mount 12C. Pressure sensor die 12B is connected to electrically energizable programmable read-only memory (EEPROM) 12F and to an analog to digital converter 12E. Signal leads 12G pass through a glass header 12H to provide connections to the electronics contained within electronics housing 16, as seen in FIG. 1. The circuitry is seen in FIG. 4.

Operation of EEPROM 12F mounted on board 12K of sensor capsule 12 connected to base unit 11 receives standardized information for utilization by the electronics contained within. The analog to digital converter 12E converts pressure applied to sensor die 12B from analog to digital form for extension to electronic control circuitry in housing 16. The functional output of the sensor capsule is a variable duty cycle. The EEPROM communications element utilizes a digital signal protocol. Also included in the sensor capsule for equalization purposes is low pressure or atmospheric input 12J. A total of eight leads, i.e. signal pins 12G pass through glass seals 12H.

Referring now to the cross-sectional view again of FIG. 3, the meter body includes at its bottom end diaphragm UG connected to vertical channel or bore 1 IF. At the bottom edge of meter body 11 is an annular recessed ring, such as 11H (semi-circular in cross section), which is utilized in engaging the projections on an industry standard type of sanitary-seal gasket which facilitates the ready assembly and disassembly from a piping system or an associated characterization or initialization system.

The meter body further includes a channel or bore 1 IE which extends to vertical channel 1 IF which is utilized for insertion of fluid within the housing after which a plug is inserted into the opening HE. This operation takes place after the unit has been assembled to a sensor capsule 12. Openings 11D and 11C as shown in FIG. 2 provide for atmospheric venting.

It should be noted in referring to FIG. 1, that within the housing section 16, connected to the sensor capsule 12, is the necessary electronic circuitry responsive to analog pressure variations detected at the meter body and extended in digital form to provide the necessary detailed information about pressure conditions determined by the meter body assembly. As noted above, the electronics include memory functions performed by an EEPROM and A/D conversion circuitry as seen in FIG. 4, which are integral to the sensor assembly.

Initially, the unit is connected to a characterization system for initialization or standards establishment. The characterization system is connected to the bottom of meter body 11, to provide known reference conditions to the EEPROM 12F of the sensor unit so that its performance can be mapped over a full range of operating conditions. Data collected during characterization is subsequently utilized by the transmitter software to provide a corrected digital output. The present unit facilitates the task of physically interfacing the meter body assembly, such as 21, to the characterization system which in the past has been a time-consuming, costly operation.

This operation is facilitated by the utilization of the sanitary-seal configuration included on meter body 11. The design of meter body 21 with its inclusion of sensor capsule 12, as taught by the present invention facilitates adaptation to many specific different customer needs, and accordingly results in the reduction of the production time by a substantial amount.

While essentially only a single embodiment of the present invention has been shown, it will be obvious to those skilled in the art that numerous modifications may be made without departing from the present invention, which shall be limited only by the scope of the claims appended hereto.

Claims

WHAT IS CLAIMED IS:

1. A sensor capsule for use with an associated meter body in a pressure transmitter utilized in a continuous pressurized transmission system, said capsule comprising: a cylindrical housing adapted to engage an associated meter body; a silicon pressure sensitive die positioned within said housing; said sensor die operated in response to analog pressure changes to initiate electrical signals in response to said pressure changes, and means included in said sensor capsule to convert said electrical signals to digital form for transmission to an associated electronic control unit.

2. A sensor capsule as claimed in claim 1 wherein: said sensor capsule includes circuit means operated in response to said electrical signals to convert said signals to digital form for transmission to associated electronic control circuitry.

3. A sensor capsule as claimed in claim 1 wherein: said die is secured to said housing by a stress isolation mount.

4. A sensor capsule as claimed in claim 1 wherein: a circuit board including circuit connections to said sensor die, positioned within said housing adjacent to said die.

5. A sensor capsule as claimed in claim 4 wherein: said circuit board is constructed of ceramic material.

6. A sensor capsule as claimed in claim 1 wherein: there is further included within said capsule, memory means including circuit connections to said sensor die.

7. A sensor capsule as claimed in claim 6 wherein: said memory means comprise an electrically energizable programmable readonly memory (EEPROM).

8. A sensor capsule as claimed in claim 1 wherein: there is further included an analog to digital converter including circuit connections to said sensor die.

9. A sensor capsule as claimed in claim 4 wherein: there is provided a plurality of signal leads extending from said circuit board through signal pins to extend signals representative of said pressure changes.

10. A sensor capsule as claimed in claim 9 wherein: said signal leads are extended from said cylindrical housing through a glass seal.