Title of Invention	"A METHOD OF PREPARING A PRE-SOLDERED AND PRE-MOLDED SENSOR STRAIN GAUGE FOR MEASUREMENT OF APPLIED STRESS ON A COMPONENT"
Abstract	A method of preparing pre-soldered and pre-molded sensor strain gauge for measurement of applied stress on a component comprising the steps of placing a sensor gauge (1) on a glass bottom (2) on covering the whole face of the gauge by double sided tape (3), placing around the tape covered strain gauge (1) a O-ring (4), soldering the open ends of a 25 pin connected male connector cable (5) to the soldering tabs (6) of the strain gauge and completely molding the strain gauge along the space between the gauge and the O-ring with a suitable agent and allowing the agent to get set and installing the said soldered and molded sensor strain gauge on the surface of a component by a suitable adhesive at any location for measurement of applied strain on the component.

Title of Invention

"A METHOD OF PREPARING A PRE-SOLDERED AND PRE-MOLDED SENSOR STRAIN GAUGE FOR MEASUREMENT OF APPLIED STRESS ON A COMPONENT"

Abstract

A method of preparing pre-soldered and pre-molded sensor strain gauge for measurement of applied stress on a component comprising the steps of placing a sensor gauge (1) on a glass bottom (2) on covering the whole face of the gauge by double sided tape (3), placing around the tape covered strain gauge (1) a O-ring (4), soldering the open ends of a 25 pin connected male connector cable (5) to the soldering tabs (6) of the strain gauge and completely molding the strain gauge along the space between the gauge and the O-ring with a suitable agent and allowing the agent to get set and installing the said soldered and molded sensor strain gauge on the surface of a component by a suitable adhesive at any location for measurement of applied strain on the component.

Full Text	FIELD OF THE INVENTION: This invention relates to a method of preparation of pre-soldered and molded sensor strain gauges and installing those on the component while carrying out applied stress analysis. BACKGROUND OF THE INVENTION WITH PRIOR ART DISADVANTAGES: Experimental stress analysis is carried out to determine the safety and integrity of the component and design validation. The sensor used for this purpose is electrical resistance strain gauges. In the conventional method the strain gauge is installed with special adhesive at the location of interest, then carry out the soldering after installation. This method involves a lot of time for soldering and in certain cases due to poor access of the locations the installation becomes difficult and impossible. Apart from this the gauges are to be protected by proper protective coating against any damage and water spilling on the gauge incase of hydro testing. -2- Japanese patent Document JP 2001050825 has disclosed a method to shorten the machining time by completing the process from machining of a local cell to welding of a strain gauge only through injection molding. In contrast of this prior patent the present invention is using pre-soldered and pre-molded strain gauge. The strain gauge is installed on the surface of the component with suitable adhesive and not by welding. US Patent Document US 5447074 has disclosed a strain-gauge transducer comprising a substrate provided with strain gauges and pressure members which deform the substrate via transfer elements, which transmit an applied force. The transfer elements comprise bars molded from an elastomer in a common molding operation. The transducer can be used for the construction of scales or touch tablets. In contrast the present invention is different in the sense that the strain gauge itself is pre-soldered and pre-molded. Also the strain gauge can be installed on any engineering components for measurement of applied strains. -3- Japanese patent document JP 545069485 has obtained a good resin sealed body by mounting a strain gauge and thermocouple on the inner side face of a cylinder of the same material as that of the member to be sealed, molding sealing resin on the side face and measuring the tightening stress produced at that time in association with temperature. Whereas the present invention has proposed that before installing the strain gauge on any part of any engineering component, the gauge itself is pre-soldered and molded. Japanese patent document JP 61065104 has taught to save power in a field by coating the periphery of a connection part between gauge leads and lead wires with a synthetic resin mold, forming a plane fitting part on its external surface and then forming a connection part protecting body on the end part from which the leads and the lead wires are led out. The present invention has proposed that the entire gauge is pre-soldered and molded prior to installation. The objective is to enable easy installation of strain gauges in difficult access locations apart from protection against damages. -4- Japanese patent document JP 62110151 has disclosed a method to enable highly accurate measurement without generating deterioration by molding a thermosetting resin around a metal pipe and after curing strain measuring gauge to the inside of the pipe to pull out the resin. In the proposed invention the entire gauge is pre-soldered and molded prior to installation. The objective is to enable easy installation of strain gauges in difficult access locations. Also it can be installed on any contour in pipes and plates. US patent document 9053907 has taught a method to provide a strain gauge with a protector in which the disconnection of gauge leads and lead wires does not occur and which can be reduced in size, weight, and cost, an stuck to an object to be measured and has a high moisture resistance and a high impact resistance. -5- A gauge-housing member has an open end on the side of an object to be measured and a square pipe like end closed by the middle section of a fitting member on the other side. In the member a strain gauge which is positioned so that the gauge protrudes slightly towards the object to be measured, gauge leads used as connecting members, a relay terminal block and the front end sections of cable cores are housed and the gauge, leads, terminal block and front end sections are integrally molded. The member is fixed to the object to be measured by fitting the screw inserting holes formed in the member on stud bolts planted on the object to be measured and tightening nuts to the bolts. The proposed invention is entirely different and not for a specific application. Further, the strain gauge alone is pre-soldered and molded and not any other member. After the pre-soldering and molding the strain gauge can be fixed on the surface of the component using suitable adhesives. DESCRIPTION OF THE INVENTION: One object of the invention is to develop a method to pre-solder the gauges prior to fixing at the locations of interest. -6- Another object of the invention is to provide means so that the gauges can be moulded at lab itself, reduction of installation time considerably and enables reduction in operator fatigue. Yet another object of the invention is to mould with proper agent the soldered gauges for protection against any damage. A further object of the invention is to paste the produced gauge at the location of interest without any difficulty. The whole set of soldered and moulded sensor strain gauge is installed at any location on any engineering components with a suitable adhesive for measurement of stress on an object. According to the invention there is provided a method of preparing pre-soldered and pre-molded sensor strain gauge for measurement of applied stress on a component comprising the steps of placing a sensor gauge on a glass bottom on covering the whole face of the gauge by double sided tape, placing around the -7- tape covered strain gauge a O-ring, soldering the open ends of a 25 pin connected male connector cable to the soldering tabs of the strain gauge and completely molding the strain gauge along the space between the gauge and the O-ring with a suitable agent and allowing the agent to get set and installing the said soldered and molded sensor strain gauge on the surface of a component by a suitable adhesive at any location for measurement of applied stress on the component. To ascertain the safety and integrity of a pressure vessel experimental stress analysis is being carried out according to relevant standards. The sensor used for this purpose is electrical resistance strain gauges. The proposed invention will be better understood from the description with reference to the accompanying drawings in which Fig. 1 to 4 illustrates the methodology of preparation of pre-soldering and molded strain gauges, wherein Figure 1 represents an electrical resistance strain gauge sensor. -8- Figure 2 represents schematically the strain gauge placed on a glass bottom with a double sick tape with the face of the gauge in contact with glass bottom. Figure 3 represents schematically an O-ring placed around the strain gauge and Figure 4 represents schematically a multiwire cable connection one end of which being connected to a 25 pin male connector and the other being soldered to the solder tabs of the strain gauge with O-ring attachment. The strain gauges are prepared at laboratory itself. The gauges (1) are placed on a glass bottom (2) using a double side tape (3) with the face of the gauge is in touch with the glass bottom. An O-ring (4) is then placed around the strain gauge. Then a half a meter cable (5) is used for making the instrument connection. One end of the half a meter cable is connected to a 25 pin male connector not shown and the other end is soldered to the soldering tabs (6) of the strain gauges. Then the strain gauges are completely moulded with suitable agent (7) and allowed to get set. The entire process is done at laboratory itself and checked. -9- The invention as described and illustrated herein with a particular form of embodiment should not be read and construed in a restrictive manner as various adaptations, alterations and modifications are possible within the scope and limit of the invention as defined in the appended claims. -10- WE CLAIM: 1. A method of preparing pre-soldered and pre-molded sensor strain gauge for measurement of applied stress on a component comprising the steps of placing a sensor gauge (1) on a glass bottom (2) on covering the whole face of the gauge by double sided tape (3), placing around the tape covered strain gauge (1) a O-ring (4), soldering the open ends of a 25 pin connected male connector cable (5) to the soldering tabs (6) of the strain gauge and completely molding the strain gauge along the space between the gauge and the O-ring with a suitable agent and allowing the agent to get set and installing the said soldered and molded sensor strain gauge on the surface of a component by a suitable adhesive at any location for measurement of applied strain on the component. 2. A method of preparing pre-soldered and pre-molded strain gauge as claimed in claim 1 wherein the said gauge can be easily installed on any location of a component and on any contour in pipes and tubes. -11- -12- 3. A method as claimed in the preceeding claims wherein the strain gauge prepared is protected from any damage and water spilling on the gauge in case of hydrotesting. 4. A method of preparing a pre-soldered and pre-molded sensor strain gauge for measurement of applied strain on a component as herein described. 5. A strain gauge for measurement of applied strain on a component as prepared by the method of claim 1. A method of preparing pre-soldered and pre-molded sensor strain gauge for measurement of applied stress on a component comprising the steps of placing a sensor gauge (1) on a glass bottom (2) on covering the whole face of the gauge by double sided tape (3), placing around the tape covered strain gauge (1) a 0-ring (4), soldering the open ends of a 25 pin connected male connector cable (5) to the soldering tabs (6) of the strain gauge and completely molding the strain gauge along the space between the gauge and the O-ring with a suitable agent and allowing the agent to get set and installing the said soldered and molded sensor strain gauge on the surface of a component by a suitable adhesive at any location for measurement of applied strain on the component.

Full Text

FIELD OF THE INVENTION:
This invention relates to a method of preparation of pre-soldered and molded sensor strain gauges and installing those on the component while carrying out applied stress analysis.
BACKGROUND OF THE INVENTION WITH PRIOR ART DISADVANTAGES:
Experimental stress analysis is carried out to determine the safety and integrity of the component and design validation. The sensor used for this purpose is electrical resistance strain gauges. In the conventional method the strain gauge is installed with special adhesive at the location of interest, then carry out the soldering after installation. This method involves a lot of time for soldering and in certain cases due to poor access of the locations the installation becomes difficult and impossible. Apart from this the gauges are to be protected by proper protective coating against any damage and water spilling on the gauge incase of hydro testing.
-2-

Japanese patent Document JP 2001050825 has disclosed a method to shorten the machining time by completing the process from machining of a local cell to welding of a strain gauge only through injection molding.
In contrast of this prior patent the present invention is using pre-soldered and pre-molded strain gauge. The strain gauge is installed on the surface of the component with suitable adhesive and not by welding.
US Patent Document US 5447074 has disclosed a strain-gauge transducer comprising a substrate provided with strain gauges and pressure members which deform the substrate via transfer elements, which transmit an applied force. The transfer elements comprise bars molded from an elastomer in a common molding operation. The transducer can be used for the construction of scales or touch tablets.
In contrast the present invention is different in the sense that the strain gauge itself is pre-soldered and pre-molded. Also the strain gauge can be installed on any engineering components for measurement of applied strains.
-3-

Japanese patent document JP 545069485 has obtained a good resin sealed body by mounting a strain gauge and thermocouple on the inner side face of a cylinder of the same material as that of the member to be sealed, molding sealing resin on the side face and measuring the tightening stress produced at that time in association with temperature.
Whereas the present invention has proposed that before installing the strain gauge on any part of any engineering component, the gauge itself is pre-soldered and molded.
Japanese patent document JP 61065104 has taught to save power in a field by coating the periphery of a connection part between gauge leads and lead wires with a synthetic resin mold, forming a plane fitting part on its external surface and then forming a connection part protecting body on the end part from which the leads and the lead wires are led out.
The present invention has proposed that the entire gauge is pre-soldered and molded prior to installation. The objective is to enable easy installation of strain gauges in difficult access locations apart from protection against damages.
-4-

Japanese patent document JP 62110151 has disclosed a method to enable highly accurate measurement without generating deterioration by molding a thermosetting resin around a metal pipe and after curing strain measuring gauge to the inside of the pipe to pull out the resin.
In the proposed invention the entire gauge is pre-soldered and molded prior to installation. The objective is to enable easy installation of strain gauges in difficult access locations. Also it can be installed on any contour in pipes and plates.
US patent document 9053907 has taught a method to provide a strain gauge with a protector in which the disconnection of gauge leads and lead wires does not occur and which can be reduced in size, weight, and cost, an stuck to an object to be measured and has a high moisture resistance and a high impact resistance.
-5-

A gauge-housing member has an open end on the side of an object to be measured and a square pipe like end closed by the middle section of a fitting member on the other side. In the member a strain gauge which is positioned so that the gauge protrudes slightly towards the object to be measured, gauge leads used as connecting members, a relay terminal block and the front end sections of cable cores are housed and the gauge, leads, terminal block and front end sections are integrally molded. The member is fixed to the object to be measured by fitting the screw inserting holes formed in the member on stud bolts planted on the object to be measured and tightening nuts to the bolts.
The proposed invention is entirely different and not for a specific application. Further, the strain gauge alone is pre-soldered and molded and not any other member. After the pre-soldering and molding the strain gauge can be fixed on the surface of the component using suitable adhesives.
DESCRIPTION OF THE INVENTION:
One object of the invention is to develop a method to pre-solder the gauges prior to fixing at the locations of interest.
-6-

Another object of the invention is to provide means so that the gauges can be moulded at lab itself, reduction of installation time considerably and enables reduction in operator fatigue.
Yet another object of the invention is to mould with proper agent the soldered gauges for protection against any damage.
A further object of the invention is to paste the produced gauge at the location of interest without any difficulty.
The whole set of soldered and moulded sensor strain gauge is installed at any location on any engineering components with a suitable adhesive for measurement of stress on an object.
According to the invention there is provided a method of preparing pre-soldered and pre-molded sensor strain gauge for measurement of applied stress on a component comprising the steps of placing a sensor gauge on a glass bottom on covering the whole face of the gauge by double sided tape, placing around the
-7-

tape covered strain gauge a O-ring, soldering the open ends of a 25 pin connected male connector cable to the soldering tabs of the strain gauge and completely molding the strain gauge along the space between the gauge and the O-ring with a suitable agent and allowing the agent to get set and installing the said soldered and molded sensor strain gauge on the surface of a component by a suitable adhesive at any location for measurement of applied stress on the component.
To ascertain the safety and integrity of a pressure vessel experimental stress analysis is being carried out according to relevant standards. The sensor used for this purpose is electrical resistance strain gauges.
The proposed invention will be better understood from the description with reference to the accompanying drawings in which Fig. 1 to 4 illustrates the methodology of preparation of pre-soldering and molded strain gauges, wherein
Figure 1 represents an electrical resistance strain gauge sensor.
-8-

Figure 2 represents schematically the strain gauge placed on a glass bottom with a double sick tape with the face of the gauge in contact with glass bottom.
Figure 3 represents schematically an O-ring placed around the strain gauge and
Figure 4 represents schematically a multiwire cable connection one end of which being connected to a 25 pin male connector and the other being soldered to the solder tabs of the strain gauge with O-ring attachment.
The strain gauges are prepared at laboratory itself. The gauges (1) are placed on a glass bottom (2) using a double side tape (3) with the face of the gauge is in touch with the glass bottom. An O-ring (4) is then placed around the strain gauge. Then a half a meter cable (5) is used for making the instrument connection. One end of the half a meter cable is connected to a 25 pin male connector not shown and the other end is soldered to the soldering tabs (6) of the strain gauges. Then the strain gauges are completely moulded with suitable agent (7) and allowed to get set. The entire process is done at laboratory itself and checked.
-9-

The invention as described and illustrated herein with a particular form of embodiment should not be read and construed in a restrictive manner as various adaptations, alterations and modifications are possible within the scope and limit of the invention as defined in the appended claims.
-10-

WE CLAIM:
1. A method of preparing pre-soldered and pre-molded sensor strain
gauge for measurement of applied stress on a component comprising
the steps of placing a sensor gauge (1) on a glass bottom (2) on
covering the whole face of the gauge by double sided tape (3), placing
around the tape covered strain gauge (1) a O-ring (4), soldering the
open ends of a 25 pin connected male connector cable (5) to the
soldering tabs (6) of the strain gauge and completely molding the
strain gauge along the space between the gauge and the O-ring with a
suitable agent and allowing the agent to get set and installing the said
soldered and molded sensor strain gauge on the surface of a
component by a suitable adhesive at any location for measurement of
applied strain on the component.
2. A method of preparing pre-soldered and pre-molded strain gauge as
claimed in claim 1 wherein the said gauge can be easily installed on
any location of a component and on any contour in pipes and tubes.
-11-

-12-
3. A method as claimed in the preceeding claims wherein the strain
gauge prepared is protected from any damage and water spilling on
the gauge in case of hydrotesting.
4. A method of preparing a pre-soldered and pre-molded sensor strain
gauge for measurement of applied strain on a component as herein
described.
5. A strain gauge for measurement of applied strain on a component as
prepared by the method of claim 1.

A method of preparing pre-soldered and pre-molded sensor strain gauge for measurement of applied stress on a component comprising the steps of placing a sensor gauge (1) on a glass bottom (2) on covering the whole face of the gauge by double sided tape (3), placing around the tape covered strain gauge (1) a 0-ring (4), soldering the open ends of a 25 pin connected male connector cable (5) to the soldering tabs (6) of the strain gauge and completely molding the strain gauge along the space between the gauge and the O-ring with a suitable agent and allowing the agent to get set and installing the said soldered and molded sensor strain gauge on the surface of a component by a suitable adhesive at any location for measurement of applied strain on the component.

Documents:

http://ipindiaonline.gov.in/patentsearch/GrantedSearch/viewdoc.aspx?id=RtAddiY79xmoX4MspWHDMA==&loc=wDBSZCsAt7zoiVrqcFJsRw==

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Patent Number

268739

Indian Patent Application Number

193/KOL/2007

PG Journal Number

38/2015

Publication Date

18-Sep-2015

Grant Date

15-Sep-2015

Date of Filing

07-Feb-2007

Name of Patentee

BHARAT HEAVY ELECTRICALS LIMITED,

Applicant Address

REGIONAL OPERATIONS DIVISION(ROD), PLOT NO:9/1, DJBLOCK 3RD FLOOR, KARUNAMOYEE, SALTLAKE CITY, KOLKATA - 700091, HAVING ITS REGISTERED OFFICE AT BHEL HOUSE,SIRI FORT, NEW DELHI- 110049 INDIA

Inventors:

#	Inventor's Name	Inventor's Address
1	SURESH, SRINIVASAN	INDIAN NATIONALS OF WELDING RESEARCH INSTITUTE, BHARAT HEAVY ELECTRICALS LIMITED, TIRUCHIRAPPALLI-620 014, TAMILNADU INDIA
2	RAJU, NARASIMHAN	INDIAN NATIONALS OF WELDING RESEARCH INSTITUTE BHARAT HEAVY ELECTRICALS LIMITED, TIRUCHIRAPPALLI-620 014, TAMILNADU INDIA

PCT International Classification Number

N/A

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA