CN113465645B - Silk screen sensor assembly suitable for high-temperature and high-pressure flow working condition - Google Patents
Silk screen sensor assembly suitable for high-temperature and high-pressure flow working condition Download PDFInfo
- Publication number
- CN113465645B CN113465645B CN202110675151.7A CN202110675151A CN113465645B CN 113465645 B CN113465645 B CN 113465645B CN 202110675151 A CN202110675151 A CN 202110675151A CN 113465645 B CN113465645 B CN 113465645B
- Authority
- CN
- China
- Prior art keywords
- pipe section
- sealing
- flange
- silk screen
- screen sensor
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
- G01D11/00—Component parts of measuring arrangements not specially adapted for a specific variable
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
- G01D11/00—Component parts of measuring arrangements not specially adapted for a specific variable
- G01D11/16—Elements for restraining, or preventing the movement of, parts, e.g. for zeroising
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E30/00—Energy generation of nuclear origin
- Y02E30/30—Nuclear fission reactors
Abstract
The application provides a silk screen sensor component suitable for a high-temperature high-pressure flowing working condition, which comprises a first sealing module, a second sealing module, a silk screen sensor and a lead sealing module; the second sealing module comprises an upper pipe section, an upper connecting flange and an upper sealing flange, wherein the upper connecting flange and the upper sealing flange are arranged at two ends of the upper pipe section; the lower pipe section is provided with a lower connecting flange and a lower sealing flange which are arranged at two ends of the lower pipe section; the upper sealing flange and the lower sealing flange are arranged in a sealing and buckling mode, and the inner hole diameters of the upper pipe section and the lower pipe section are arranged in an aligned mode after buckling; the wire mesh sensor is arranged between the upper pipe section and the lower pipe section, and the edge of the wire mesh sensor is fixedly arranged on the upper sealing flange and/or the lower sealing flange; the silk screen sensor detects the data of the fluid flowing through the upper pipe section and the lower pipe section and is connected with an external circuit through a lead.
Description
Technical Field
The invention belongs to the technical field of multiphase flow parameter measurement, and particularly relates to a wire mesh sensor assembly suitable for a high-temperature high-pressure flow working condition.
Background
The silk screen sensor is used as a high-frequency intrusive gas-liquid two-phase flow parameter acquisition sensor, has the characteristics of convenience, rapidness, high resolution and the like, and can acquire abundant data such as channel full-section vacuole share, phase interface concentration, interface reconstruction imaging and the like. However, the existing silk screen sensor is mainly applied to laboratory working conditions under normal temperature and normal pressure, and the acquired data is also basically applied to basic scientific research, such as an air-water two-phase flow system.
However, in engineering practice, two-phase flow systems are usually in high-temperature and high-pressure operating conditions, which puts higher demands on the acquisition work of two-phase flow parameters. At present, the ray irradiation technology can be successfully applied to a two-phase flow system under the working condition of high temperature and high pressure, but the manufacturing cost is high, the operation is complicated, the obtained available data is very limited, and the technology is not an ideal two-phase flow parameter measuring technology. The silk screen sensor is applied to a two-phase flow system under a high-temperature and high-pressure working condition, the biggest problem existing at present is the sealing and insulating requirements of the system on the sensor, the application range of the silk screen sensor is severely limited, and the advantage of excellent two-phase flow parameter acquisition cannot be fully exerted.
In summary, there is a need to solve the problem of the wire mesh sensor that the wire mesh sensor has a high sealing performance and insulation requirement under high temperature and high pressure, so that the wire mesh sensor can stably and reliably operate under high temperature and high pressure.
Disclosure of Invention
In order to overcome the defects in the prior art, the application provides a screen sensor assembly, which comprises a first sealing module, a second sealing module, a screen sensor and a lead sealing module;
the second sealing module comprises an upper pipe section, an upper connecting flange and an upper sealing flange, wherein the upper connecting flange and the upper sealing flange are arranged at two ends of the upper pipe section; the lower pipe section is provided with a lower connecting flange and a lower sealing flange which are arranged at two ends of the lower pipe section;
the upper sealing flange and the lower sealing flange are arranged in a sealing and buckling manner, and the inner apertures of the upper pipe section and the lower pipe section are arranged in an aligned manner after buckling;
the wire mesh sensor is arranged between the upper pipe section and the lower pipe section, and the edge of the wire mesh sensor is fixedly arranged on the upper sealing flange and/or the lower sealing flange;
the silk screen sensor detects the data of the fluid flowing through the upper pipe section and the lower pipe section and is connected with an external circuit through a lead.
In one possible implementation, the silk screen sensor is arranged in a first sealing module, the first sealing module is arranged in a second sealing module, and the lead sealing module is arranged at the upper part of the second sealing module.
In one possible implementation, the second sealing module comprises an outer bolt, an outer nut, an outer gasket, a polytetrafluoroethylene gasket and a positioning groove;
the upper pipe section is assembled on the upper connecting flange in a flush manner; the upper end of the lower pipe section is assembled with the positioning groove on the lower sealing flange in a flush manner, and the lower end of the lower pipe section is assembled with the lower connecting flange in a flush manner; the upper sealing flange, the polytetrafluoroethylene gasket and the lower sealing flange are assembled in sequence, and the sealing surface is pressed through the outer bolt, the outer nut and the outer gasket.
In one possible implementation manner, the first sealing module comprises an inner bolt, an inner nut, an inner gasket, an inner pressing flange, an upper polytetrafluoroethylene gasket, a lower polytetrafluoroethylene gasket and an upper pipe section positioning groove; the lower polytetrafluoroethylene gasket, the wire mesh sensor, the upper polytetrafluoroethylene gasket and the inner pressing flange are coaxially aligned in sequence and are arranged in the positioning groove, and the sealing surface is pressed through the inner bolt, the inner gasket and the inner nut; the lower end of the upper pipe section is arranged in the upper pipe section positioning groove.
In one possible implementation manner, the lead sealing module comprises a compression bolt, a data transmission line and compression packing; the data transmission line is connected with a PCB of the silk screen sensor, the data transmission line penetrates out through a central hole of the compression material and the compression bolt, and the compression filler is compressed through the compression bolt, so that a gap between the compression filler and the data transmission line is compacted, and the sealing function is ensured.
Due to the application of the technical scheme, compared with the prior art, the invention has the following beneficial effects: the silk screen sensor subassembly that this application provided is through the triple sealed effect that sets up first sealed module, the sealed module of second and the sealed module of lead wire, has effectively solved the sealed problem of silk screen sensor during operation, external insulation problem and data line and has drawn forth the problem, has guaranteed that the silk screen sensor can be in high temperature high pressure operating mode steady operation.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the description below are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.
Embodiments of the invention are further described below with reference to the accompanying drawings:
FIG. 1 is a schematic structural diagram of a wire mesh sensor assembly provided by an exemplary embodiment of the present invention;
FIG. 2 is a top view of a screen sensor assembly provided in accordance with an exemplary embodiment of the present invention;
FIG. 3 is a cross-sectional view of a wire mesh sensor assembly provided by an exemplary embodiment of the present invention;
fig. 4 is a partially enlarged view of fig. 3 at B.
Description of the reference numerals:
1-upper connecting flange; 2-upper pipe section; 3, external bolts; 4-external nut; 5-an outer gasket; 6-upper sealing flange; 7-lower sealing flange; 8-a hold-down bolt; 9-a data transmission line; 10-lower pipe section; 11-a lower connecting flange; 12-compacting the filler; 13-internal bolts; 14-polytetrafluoroethylene gasket; 15-internal nut; 16-an inner gasket; 17-internally pressing the flange; 18-applying a polytetrafluoroethylene gasket; 19-positioning grooves; 20-a PCB board; 21-lower polytetrafluoroethylene spacer; 22-upper pipe section positioning groove.
Detailed Description
The present invention will be described in detail with reference to specific examples. The following examples will assist those skilled in the art in further understanding the invention, but are not intended to limit the invention in any way. It should be noted that variations and modifications can be made by persons skilled in the art without departing from the concept of the invention. All falling within the scope of the present invention.
The present invention is further described in detail below with reference to fig. 1 to 4.
As shown in fig. 1, a screen sensor assembly suitable for high-temperature and high-pressure flow conditions includes a first sealing module, a second sealing module, a screen sensor, and a lead sealing module.
The wire mesh sensor includes a PCB board 20 disposed inside a first sealing module disposed inside a second sealing module, and a lead sealing module disposed on an upper portion of the second sealing module.
The second sealing module comprises an upper connecting flange 1, an upper pipe section 2, an outer bolt 3, an outer nut 4, an outer gasket 5, an upper sealing flange 6, a lower sealing flange 7, a lower pipe section 10, a lower connecting flange 11, a polytetrafluoroethylene gasket 14 and a positioning groove 19. The upper pipe section 2 is assembled on the upper connecting flange 1 in a flush manner and is fixed in a welding mode; the upper end of the lower pipe section 10 is assembled with a positioning groove 19 on the lower sealing flange 7 in a flush manner, and the lower end of the lower pipe section 10 is assembled with a lower connecting flange 11 in a flush manner and is fixed in a welding manner; the upper sealing flange 6, the polytetrafluoroethylene gasket 14 and the lower sealing flange 7 are assembled in sequence, and the sealing surface is pressed tightly through the outer bolt 3, the outer nut 4 and the outer gasket 5.
The first sealing module comprises an inner bolt 13, an inner nut 15, an inner gasket 16, an inner pressing flange 17, an upper polytetrafluoroethylene gasket 18, a lower polytetrafluoroethylene gasket 21 and an upper pipe section positioning groove 22. The lower polytetrafluoroethylene gasket 21, the PCB 20 of the screen sensor, the upper polytetrafluoroethylene gasket 18 and the inner pressing flange 17 are coaxially aligned in sequence and are arranged in the positioning groove 19, the sealing surface is pressed through the inner bolt 13, the inner gasket 16 and the inner nut 15, and the PCB 20 of the screen sensor is ensured to be in an insulating state with the outside. The lower end of the upper pipe section 2 is arranged in the upper pipe section positioning groove 22, so that the dislocation phenomenon caused by misalignment of the upper pipe section 2 and the lower pipe section 10 is avoided.
The lead sealing module comprises a compression bolt 8, a data transmission line 9 and a compression packing 12. The data transmission line 9 is connected with the PCB 20 of the silk screen sensor, and the outer surface of the data transmission line 9 is covered by a high-temperature-resistant insulating material, so that the reliability of data transmission is ensured; the data transmission line 9 penetrates through the center holes of the compression material 12 and the compression bolt 8, and then the compression packing 12 is compressed through the compression bolt 8, so that a gap between the compression packing 12 and the data transmission line 9 is compacted, and the sealing function is ensured.
Through the triple sealing effect of the first sealing module, the second sealing module and the lead sealing module, the sealing problem, the external insulation problem and the data line leading-out problem of the PCB 20 of the silk screen sensor during the operation are solved, and the PCB 20 of the silk screen sensor can stably operate under the working condition of high temperature and high pressure.
The inventive concept is explained in detail herein using specific examples, which are only provided to help understanding the core idea of the present invention. It should be understood that any obvious modifications, equivalents and other improvements made by those skilled in the art without departing from the spirit of the present invention are all included in the scope of the present invention.
Other embodiments of the present application will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of the invention following, in general, the principles of the application and including such departures from the present disclosure as come within known or customary practice within the art to which the invention pertains. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the application being indicated by the following claims.
It will be understood that the present application is not limited to the precise arrangements described above and shown in the drawings and that various modifications and changes may be made without departing from the scope thereof. The scope of the application is limited only by the appended claims.
It should be understood that reference herein to "a plurality" means two or more. "and/or" describes the association relationship of the associated object, indicating that there may be three relationships, for example, a and/or B, which may indicate: a exists alone, A and B exist simultaneously, and B exists alone. The character "/" generally indicates that the former and latter associated objects are in an "or" relationship.
It will be understood by those skilled in the art that all or part of the steps for implementing the above embodiments may be implemented by hardware, or may be implemented by a program instructing relevant hardware, where the program may be stored in a computer-readable storage medium, and the storage medium may be a read-only memory, a magnetic disk or an optical disk.
The above description is only exemplary of the present application and should not be taken as limiting the present application, as any modification, equivalent replacement, or improvement made within the spirit and principle of the present application should be included in the protection scope of the present application.
Claims (3)
1. A silk screen sensor component suitable for the high-temperature and high-pressure flowing working condition is characterized by comprising a first sealing module, a second sealing module, a silk screen sensor and a lead sealing module;
the first sealing module comprises an inner bolt, an inner nut, an inner gasket, an inner pressing flange, an upper polytetrafluoroethylene gasket, a lower polytetrafluoroethylene gasket and an upper pipe section positioning groove;
the second sealing module comprises an outer bolt, an outer nut, an outer gasket, a polytetrafluoroethylene gasket and a positioning groove; the upper pipe section is assembled on the upper connecting flange in a flush manner; the upper end of the lower pipe section is assembled with the positioning groove on the lower sealing flange in a flush manner, and the lower end of the lower pipe section is assembled with the lower connecting flange in a flush manner; the upper sealing flange, the polytetrafluoroethylene gasket and the lower sealing flange are assembled in sequence, and the sealing surface is pressed tightly through the outer bolt, the outer nut and the outer gasket;
the upper sealing flange and the lower sealing flange are arranged in a sealing and buckling mode, and the inner hole diameters of the upper pipe section and the lower pipe section are arranged in an aligned mode after buckling;
the silk screen sensor is arranged between the upper pipe section and the lower pipe section, and the edge of the PCB of the silk screen sensor is fixedly arranged on the upper sealing flange and/or the lower sealing flange;
the silk screen sensor detects the data of the fluid flowing through the upper pipe section and the lower pipe section and is electrically connected with the outside through a lead;
the silk screen sensor is arranged in the first sealing module, the first sealing module is arranged in the second sealing module, and the lead sealing module is arranged at the upper part of the second sealing module.
2. The silk screen sensor assembly of claim 1, wherein the lower teflon gasket, the silk screen sensor, the upper teflon gasket and the inner pressing flange are coaxially aligned in sequence and are arranged in the positioning groove, and the sealing surface is pressed by the inner bolt, the inner gasket and the inner nut; the lower end of the upper pipe section is arranged in the upper pipe section positioning groove.
3. The wire mesh sensor assembly of claim 1, wherein the lead sealing module comprises a compression bolt, a data transmission line, a compression packing; the data transmission line is connected with a PCB of the silk screen sensor, the data transmission line penetrates out through a central hole of a compression material and a compression bolt, and the compression packing is compressed through the compression bolt, so that a gap between the compression packing and the data transmission line is compacted, and the sealing function is ensured.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110675151.7A CN113465645B (en) | 2021-06-17 | 2021-06-17 | Silk screen sensor assembly suitable for high-temperature and high-pressure flow working condition |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110675151.7A CN113465645B (en) | 2021-06-17 | 2021-06-17 | Silk screen sensor assembly suitable for high-temperature and high-pressure flow working condition |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN113465645A CN113465645A (en) | 2021-10-01 |
| CN113465645B true CN113465645B (en) | 2023-03-14 |
Family
ID=77870356
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202110675151.7A Active CN113465645B (en) | 2021-06-17 | 2021-06-17 | Silk screen sensor assembly suitable for high-temperature and high-pressure flow working condition |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN113465645B (en) |
Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103453932A (en) * | 2013-06-04 | 2013-12-18 | 国家电网公司 | Low temperature liquid temperature and pressure measuring lead device |
| CN204127527U (en) * | 2014-10-20 | 2015-01-28 | 中国核动力研究设计院 | A kind of flange sealing structure |
| CN106499893A (en) * | 2016-12-28 | 2017-03-15 | 核动力运行研究所 | A kind of multiple-sealed flange with leakage monitoring function |
| KR20170052864A (en) * | 2015-11-05 | 2017-05-15 | 대우조선해양 주식회사 | Adjustable wire-mesh sensor |
| CN206290866U (en) * | 2016-12-07 | 2017-06-30 | 天津渤化石化有限公司 | Flange gasket |
| CN107269998A (en) * | 2017-07-28 | 2017-10-20 | 中国核动力研究设计院 | Suitable for the insulation and sealing structure of cylinder transmission of electricity structure under high-temperature and high-pressure conditions |
| CN207046862U (en) * | 2017-06-30 | 2018-02-27 | 歌尔科技有限公司 | A kind of environmental sensor |
| WO2018142102A1 (en) * | 2017-02-01 | 2018-08-09 | Johnson Matthey Public Limited Company | System and method for monitoring a flange joint assembly |
| CN208705261U (en) * | 2018-08-20 | 2019-04-05 | 天津市合力金属结构有限公司 | A kind of ECT sensor |
| US20200400520A1 (en) * | 2019-06-21 | 2020-12-24 | Honeywell International Inc. | Micro-molded fluid pressure sensor housing |
-
2021
- 2021-06-17 CN CN202110675151.7A patent/CN113465645B/en active Active
Patent Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103453932A (en) * | 2013-06-04 | 2013-12-18 | 国家电网公司 | Low temperature liquid temperature and pressure measuring lead device |
| CN204127527U (en) * | 2014-10-20 | 2015-01-28 | 中国核动力研究设计院 | A kind of flange sealing structure |
| KR20170052864A (en) * | 2015-11-05 | 2017-05-15 | 대우조선해양 주식회사 | Adjustable wire-mesh sensor |
| CN206290866U (en) * | 2016-12-07 | 2017-06-30 | 天津渤化石化有限公司 | Flange gasket |
| CN106499893A (en) * | 2016-12-28 | 2017-03-15 | 核动力运行研究所 | A kind of multiple-sealed flange with leakage monitoring function |
| WO2018142102A1 (en) * | 2017-02-01 | 2018-08-09 | Johnson Matthey Public Limited Company | System and method for monitoring a flange joint assembly |
| CN207046862U (en) * | 2017-06-30 | 2018-02-27 | 歌尔科技有限公司 | A kind of environmental sensor |
| CN107269998A (en) * | 2017-07-28 | 2017-10-20 | 中国核动力研究设计院 | Suitable for the insulation and sealing structure of cylinder transmission of electricity structure under high-temperature and high-pressure conditions |
| CN208705261U (en) * | 2018-08-20 | 2019-04-05 | 天津市合力金属结构有限公司 | A kind of ECT sensor |
| US20200400520A1 (en) * | 2019-06-21 | 2020-12-24 | Honeywell International Inc. | Micro-molded fluid pressure sensor housing |
Non-Patent Citations (3)
| Title |
|---|
| Wire-mesh sensors for high-resolving two-phase flow studies at high pressures and temperatures;Heiko Pietruske 等;《Flow Measurement and Instrumentation》;20071231;第18卷(第2期);第87-94页 * |
| 俞斌.基于丝网传感器的气水两相流可视化测量方法研究.《中国优秀硕士学位论文全文数据库(基础科学辑)》.2019,(第4期),第65-74页. * |
| 基于丝网传感器的气水两相流可视化测量方法研究;俞斌;《中国优秀硕士学位论文全文数据库(基础科学辑)》;20190415(第4期);第65-74页 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN113465645A (en) | 2021-10-01 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN113465645B (en) | Silk screen sensor assembly suitable for high-temperature and high-pressure flow working condition | |
| CN101713460A (en) | Sealing structure of combined sealing member | |
| CN109817432A (en) | End shield connector and bushing shell for transformer | |
| CN209544114U (en) | End shield connector and bushing shell for transformer | |
| CN211117563U (en) | Sealing structure for high-voltage test section electrical insulation | |
| CN215771495U (en) | Radio frequency microwave assembly | |
| CN103292767B (en) | A kind of detection method of flange seal part hermetic separation amount | |
| CN206931983U (en) | Cable shielding joint | |
| CN108679225A (en) | A kind of oil enveloping structure of motor | |
| CN105179693A (en) | Pressure vessel sensor lead guiding and sealing device | |
| CN215600413U (en) | Electric pile insulation packaging structure | |
| CN115148382A (en) | Electrical penetration for a pressure vessel, method of assembly | |
| CN109827693B (en) | Pressure-welding type power semiconductor device internal pressure distribution measuring system | |
| CN210182725U (en) | Cable connection composite structure of short tail type coaxial radio frequency connector | |
| CN217422306U (en) | Sealing structure of safety valve | |
| CN113280867B (en) | Silk screen sensor assembly for measuring fluid parameters in prototype rod bundle channel | |
| CN216477186U (en) | Split flange for high-temperature and high-pressure environment simulation cabin | |
| CN213584349U (en) | Novel electric connector | |
| CN211507991U (en) | Connector device and radio frequency device with same | |
| CN105470705A (en) | Weldable mixed metal package housing used for quick plugging | |
| CN109066447A (en) | A kind of gas insulated bushing end seal structure | |
| CN213905568U (en) | Novel cavity filter | |
| CN219436257U (en) | Connecting piece structure and equipment | |
| CN203532735U (en) | Insulation sealing device | |
| JP7376709B1 (en) | connection device |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant | ||
| CP01 | Change in the name or title of a patent holder |
Address after: 200240 No. 800, Dongchuan Road, Shanghai, Minhang District Patentee after: SHANGHAI JIAO TONG University Patentee after: Shanghai Nuclear Engineering Research and Design Institute Co.,Ltd. Address before: 200240 No. 800, Dongchuan Road, Shanghai, Minhang District Patentee before: SHANGHAI JIAO TONG University Patentee before: SHANGHAI NUCLEAR ENGINEERING RESEARCH & DESIGN INSTITUTE Co.,Ltd. |
|
| CP01 | Change in the name or title of a patent holder |