US3364958A

US3364958A - Method of and structure for pressurizing tube sections

Info

Publication number: US3364958A
Application number: US467237A
Authority: US
Inventors: William E Sartor; David M Martin
Original assignee: Calumet and Hecla Inc
Current assignee: Calumet and Hecla Inc
Priority date: 1965-06-28
Filing date: 1965-06-28
Publication date: 1968-01-23
Anticipated expiration: 1985-01-23
Also published as: SE333486B; DE1551569B2; DE1551569A1; BE679679A; FR1476330A; GB1108144A

Description

Jan. 23, 1968 w. E. SARTOR ET AL 3,364,958

METHOD OF AND STRUCTURE FOR PRESSURIZING TUBE SECTIONS Filed June 28, 1965 2 Sheets-Sheet 1 RELAY RELAY 94 1 TIMER fm TIMER /36 BELL BELL LIMIT 98 A LIMIT SWITCH 26 SWITCH 50 505 V '8 L v S0 05 NITROGEN 88 86 7 I2 24 3O 32 NITROGEN so 92 Io 34 28 I56 36 FG.6

l52- I50 F l I 1 .L I '42 I62 I60 I I i I I /l48 L INVENTORS WILLIAM E. SARTOR ATTORNEYS Jan. 23, 1968 w. E. SARTOR ET AL 3,364,958

METHOD OF AND STRUCTURE FOR PRESSURIZING TUBE SECTIONS 2 Sheets-Sheet 2 Filed June 28, 1965 R m 00 N R m: 0 m S T w 2W om w 0: mm; 15 M .F I- t mm LV mm mm M m 0E mm m 0E f ow N-\ s 3 E 3 E vw ow E ik K /\wN J vv52 e Om mm mh mm mm mm mm N QE United States Patent Ofitice 3,33%,958 Patented Jan. 23, 1968 3,364,958 METHOD OF AND STRUCTURE FOR PRESSURIZING TUBE SECTIONS William E. Sartor, Allen Park, and David M. Martin, Birmingham, Mich, assignors to Calumet & Hecla, Inn, Allen Park, MiclL, a corporation of Michigan Filed June 28, 1965, Ser. No. 467,237 16 Claims. (Cl. 141-4) ABSTRACT OF THE DISCLOSURE Structure for purging and pressurizing tube sections in combination with plugs for the ends of the tube sections by passing gas under pressure into one end of a tube to purge air from the tube, plugging both ends of the tube, inserting a needle through the plug in one end of the tube and pressurizing the tube with gas through the needle including separate tube purging apparatus and plug piercing and inserting apparatus. The tube purging apparatus includes a tube purging tool having telescoping parts operably associated with a switch and an axial passage therethrough connected to a source of gas under pressure operable on insertion of one end of the tool into one end or" a tube to be purged to close a switch and pass gas through the tool into the tube. The plug piercing and inserting apparatus includes a plug piercing and inserting tool having telescoping parts operably associated with a switch and an axial passage therethrough connected to a source of gas under pressure whereby on plugging one end of the tube and inserting a plug in the other end of the tube with the plug piercing and inserting tool and telescoping the relative parts thereof the plug in the other endof the tube is pierced and the switch is closed to connect the source or" gas under pressure with the interior of the tube to pressurize the tube.

In accordance with the invention structure is provided in conjunction with the switches for timing the purging of the tube and the pressurizing of the tube to insure complete purging of air from the tube before pressurizing is started and to insure a predetermined pressure in the pressurized tube. Structure for indicating the pressure of the pressurized tube is also disclosed in conjunction therewith.

In the past, tubes, such as used in refrigeration systems and the like have been subject to undesirable oxidation during elevated temperature joining operations and the like. The filling of short sections of the tube used for joining with an inert gas, such as nitrogen under pressure, has been found to reduce the formation of oxides during joining to the point where the oxides are not objectionable.

It is an object of the present invention to provide an improved method of pressurizing tube sections and the like.

Another object is to provide improved structure for pressurizing tube sections and the like.

Another object is to provide a method of pressurizing a tube section comprising passing gas into the tube to purge the air therefrom, placing a plug in each end of the tube after the tube is purged of air, subsequently inserting a hollow needle through one of the plugs into the tube and passing gas through the needle into the tube to pressurize the tube.

Another object is to provide a method as set forth above and further including the step of timing the initial passing of gas into the tube to insure complete purging of the tube.

Another object is to provide a method as set forth above and further including the step of timing the pressurizing of the tube with the gas to insure providing a desired pressure in the tube.

Another object is to provide structure for pressurizing tube sections comprising apparatus for purging the tube of air including a purging tool, a source of nitrogen under pressure, a valve positioned between the source of nitrogen under pressure and the purging tool and means for actuating the valve for a predetermined time on insertion of the purging tool into one end of the tube, plugs for both ends of the tube and tube pressurizing apparatus including a plug piercing and inserting tool connected to a source of nitrogen under pressure, a valve positioned between the plug piercing and inserting tool and the source of nitrogen under pressure and means operable in response to insertion of the plug piercing and inserting tool through a plug in one end of the tube for actuating the valve for a predetermined time.

Another object is to provide apparatus for purging a tube of air including a purging tool, a source of nitrogen under pressure, a valve positioned between the source of nitrogen under pressure and the purging tool and means for actuating the valve for a predetermined time on insertion of the purging tool into one end of the tube.

Another object is to provide apparatus for pressurizing a tube having plugs in both ends including a plug piercing and inserting tool connected to a source of nitrogen under pressure, a valve positioned between the plug piercing and inserting tool and the source of nitrogen under pressure and means operable in response to insertion of the plug piercing and inserting tool through one of the plugs into one end of the tube for actuating the valve for a predetermined time.

Another object is to provide a tool for purging a section of tubing of air comprising a handle having a passage therethrough, a hollow cylindrical housing telescopically received over one end of the handle, a point on the other end of the housing having an opening extending therethrough and a hollow core secured in the passage through the handle and passing through the opening in the point and resilient means for urging the housing outwardly of the handle.

Another object is to provide a plug piercing and inserting tool including a handle having a passage extending therethrough, a hollow cylindrical housing one end of which is telescopically received over one end of the handle, a point secured over the other end of the hollow cylindrical housing having an opening extending therethrough and a reduced outer end, a hollow needle extending through the housing and point, chuck means for securing the hollow needle in a fixed position with respect to the handle and resilient means urging the housing outwardly of the handle.

Another object is to provide pressure indicating structure including a pressure gage, a conduit connected at one end to the pressure gage and a hollow plug'piercing needle connected to the other end of the conduit.

Another object is to provide a method of and structure for pressurizing tube sections and the like which is simple, economical and efficient.

Other objects and features of the invention will become apparent as the description proceeds, especially when taken in conjunction with the accompanying drawings, illustrating a preferred embodiment of the invention, wherein:

FIGURE 1 is a diagrammatic representation of tube pressurizing structure constructed in accordance with the invention for practicing the method of the invention.

FIGURE 2 is a longitudinal section view of the purging tool of the tube pressurizing apparatus illustrated in FIG- URE 1.

FIGURE 3 is a partial elevation view of the purging tool illustrated in FIGURE 2.

FIGURE 4 is a longitudinal section view of the plug piercing and inserting tool of the tube pressurizing apparatus illustrated in FIGURE 1.

FIGURE 5 is an elevation view of the pressure indicating structure of the tube pressurizing apparatus illustrated in- FIGURE 1.

FIGURE 6 is a schematic diagram of the electric circuit of the tube purging apparatus and tube pressurizing apparatus of the tube pressurizing structure illustrated in FIGURE 1.

With particular reference to the figures of the drawing, one embodiment of the present invention will now be considered in detail. a

The structure 10 for pressurizing the tube section 12 illustrated in FIGURE 1 includes tube purging apparatus 14 for purging air from the tube 12,

plugs

16 and 18 for sealing the ends of the purged tube 12 and tube pressurizing apparatus 20 for pressurizing the sealed tube 12. The tube pressurizing structure 18 further includes. a pressure indicator 22, best shown in FIGURES, for calibrating the tube pressurizing apparatus 20.

In operation an inert gas is blOWn into the end 24 of tube 12 from the tube purging apparatus 14 to replace the air in the tube 12. The

ends

24 and 26 of the tube 12 are then sealed with

plugs

16 and 18. The tube 12 is thereafter pressurized with the inert gas by means of the plug piercing and inserting apparatus 28 through the plug 18.

More specifically the tubepur ing apparatus 14 includes a source of nitrogen under pressure 28, a tube purging tool 3t), a conduit 32 connecting the source of nitrogen 28 and the tube purging tool having a solenoid operated valve 34 therein. The tube purging apparatus further includes an electric circuit 36, as shown in FIGURE 6. The electriccircuit includes a source of electrical energy 38, a limit switch 40, relay 42, timer 44 and indicating bell or buzzer 46 along with the solenoid valve 34.

The purging tool, as illustrated best in FIGURES 2 and 3, includes a cylindrical handle 48 having an axially extending passage 59 located centrally thereof. which is adapted to receive conduit 32 at end 52 thereof, a hollow cylindrical housing 54 having an end 56 sleeved over the end 58 of the handle 48'for telescopic movement relative thereto and purging tool point 61} secured over the other end 62 of housing 54 by means of pins 64 secured thereto positioned within the opposite right angle slots 66 in the end 62 of housing 54.

The point 60 is provided with an axially extending hollow cylindrical flange 68 extending away from the handle 48, as shown, and surrounding the opening 70 through point 68. A sealing member 72 is secured to the surface 74 of the point 68 for engagement with the end 24 of the tube section 12 in operation as will be considered subsequently.

The housing 54 is secured to the handle 48 by means of the pins 76 extending perpendicularly therefrom in conjunction with the slots 78 in the housing, as best shown in FIGURE 3. The slots 78 extend from the end 56 of the housing 54 and are oiTset to provide ease of assembly of the purging tool 30.

A hollow core 80 is threadedly received in the passage 50 through the handle 48 at the end 58 of the handle 48 and extends axially of the handle and through the passage 70 in the point 60 of the purging tool 30. The spring 82 resiliently biases the housing 54 outwardly of the end 58 of the handle 48.

The solenoid operated valve 34 and the components of the electric circuit 36 including the source of electrical energy 38, limit switch 48, relay 42, timer 44 and bell or buzzer 46 are well known commercially and are in fact items purchased off the shelf so that they will not be considered in detail herein, except as to their operation as connected, which will be considered subsequently in the detail operation of the tube pressurizing structure 10.

The

plugs

16 and 18 are similarly known articles of cornmerce and will not be considered in detail herein, except to point out that the plug 18 is provided with a recess 84 in the outer surface thereof, as shown best in FIGURE 4,

and the

plugs

16 and 18 are constructed of resilient material which is self-sealing On being pierced by a hollow needle and may, for example, be constructed of rubber.

The tube pressurizing apparatus 20 includes the plug piercing and inserting tool 86, a conduit 88 connecting the plug piercing and inserting tool 86 with a source of nitrogen under pressure 90 through a solenoid operated valve 92. The source of nitrogen under pressure may be the same source as the source of nitrogen under pressure 28 or may be a different source, as shown in FIGURE 1.

The tube pressurizing apparatus 20 further includes an electric circuit 84 in all respects similar to the electric circuit 36 including a source of electric energy 96, limit switch 98, relay 100, timer 102 and bell 103. As before the electric circuit 94 operates to open the valve 92 to permit nitrogen from the source of nitrogen under pressure 99 to pass to the plug piercing and inserting tool 86 on closing of the limit switch 98 for a predetermined time to pressurize the tube 12, 'as will be considered in more detail subsequently.

The plug inserting and piercing tool 86 includes a cylindrical handle 184 having an axially extending passage 196 therein with means for connecting to the conduit 88 at the end 108 thereof and an enlarged diameter portion 118, the outer end of which is threaded at the end 112. thereof. The hollow cylindrical housing 114 has one end 116 sleeved over the end 112 of the handle 104 and is telescopically movable with respect to the handle 104. The housing 114 is guided in telescopic movement along the handle 104 by means of the pins 118 secured to the handle 104 and the slots 120, similar to the slots 78 of the purging tool housing 54 in the housing 114.

A plug inserting point 122 is secured on the other end 124 of the housing 114 by right angle slots 126 in the end 124 of the housing 114 and the pins 128 on the point 122. The point 122 is provided with an axially extending opening 130. i Y

A hollow needle 132 extends axially of the handle104 and point 122 through the passages 106 and therein and is held in a predetermined position with respect to the handle 104 by means of the resilient chuck 134 positioned in the enlarged diameter portion 110 of passage 186 which istightened in the passage 106 by means of the threaded chuck adjustment nut 136 in engagement therewith. The housing 114 is urged axially outwardly of the handle 104 by means of the spring 138 operable between the chuck adjusting member 136 and point 122.

The pressure indicator 22, as shown best in FIGURE 5, includes a pressure indicator 140, a conduit 142 connected to the pressure indicator and a hollow needle 144 adapted to be inserted through plug 16 into the tube 12 whereby the pressure in the tube 12 is recorded on the pressure indicator 140. i

The over-all operation of the tube pressurizing structure 10 will be considered in conjunction with the schematic diagram of the electric circuit 36 illustrated in FIGURE 6.

Before the

plugs

16 and 18 are placed in the tube 12 the tube purging tool 30 connected to conduit 32 so that nitrogen under pressure from the source of nitrogen 28 will pass through passage 50 on opening of the solenoid actuated valve 34 and connected to the limit switch 40 so that the limit switch 48 will be closed on substantially complete telescoping of the housing 54 over the end 58 of the handle 48 as the housing 54 is positioned over the end 24 of the tube 12 with the sealing member 72 on the point 69 in contact with the end of the tube 24.

The handle 48 of the purging tool 30 is then moved toward the end 24 of the tube 12 which is held in a fixed position to telescope the housing 54 over the handle 48 in opposition to the bias provided by spring 82. The limit switch 40, as shown schematically in FIGURE 6, is closed and length.

as the core 80 extends into the now sealed end 24 of tube 12. Closing the limit switch 40 provides an energizing path for the relay coil 146 through normally closed contacts 147 between the

conductors

148 and 150 on opposite sides of the secondary winding 152 of the transformer 154, the primary winding 156 of which is connected to the source of alternating electric energy 158. The source of alternating electric energy 158 and transformer 154 make up the source of electric energy 38.

Energizing the coil 146 of the relay 42 closes the normally

open contacts

160 and 152 of the relay 42. Closing the contacts 160 provides a circuit through the solenoid 161 of valve 34 and the parallel hell or buzzer 46 through contacts 160 between the

conductors

148 and 150 so that the valve 34 is open. Nitrogen under pressure from the source 28 is thus passed through the tube purging tool 30 and into the tube 12 to purge the air in the tube 12 out of the end 26 of the tube 12.

Closing the contacts 162 energizes the coil 164 of the timer 44 through the contacts 162 and between the

conductors

148 and 150. Energizing the coil 164 of the timer 44 causes the normally closed contacts 147 to open and the normally open contacts 166 to close at the end of a predetermined time. The circuit through the relay coil 146 is thus broken after the predetermined time whereby the

contacts

160 and 162 resume their normal open condition and the circuit through the solenoid 161 is broken to close the valve 34. Thus, after a predetermined time which is sufficient to permit complete purging of the tube 12, the nitrogen is no longer passed through the purging tool 30.

A plug 16 which may be of rubber, as previously indicated, is then inserted in the end 24 of the tube 12 and a similar plug having a recess 84 therein is positioned over the point 122 of the plug piercing and inserting tool 86 and is inserted in the end 26 of the tube 12 on application of pressure from the plug piercing and inserting tool 86.

When the plug 18 is firmly positioned in the end 26 of the tube 12 further movement of the handle 104 of the plug piercing and inserting tool 86 will cause telescoping of the housing 114 over the end 112 of the handle 104 and consequent movement of the handle 104 and the hollow needle 132 carried thereby toward the plug 84 in opposition to the bias provided by the spring 138. The needle 132 will pierce the plug 18 as the housing 114 nears its maximum telescoped position on the handle 104, at which time the limit switch 98 is actuated whereby the valve 92 is energized for a predetermined time, as determined by the relay 100 and timer 102, the detailed operation of which was considered in the operation of the circuit 36 in conjunction with the operation of the tube purging tool 30.

The valve 92 is opened for a suflicient length of time to permit the required amount of nitrogen under pressure to pass through the needle 132 to provide the predetermined pressure in the tube 12. Withdrawal of the tube piercing and inserting tool 86 from the plug 18 is then accomplished with the plug 18 sealing the opening as the needle 132 is withdrawn.

To insure the proper pressure in the tube 12 for each diiferent diameter and length of tube 12, the time which the valve 92 is opened may first be calibrated by piercing the plug 16 with the needle 144 of the pressure indicating apparatus 22 and determining the required time by determining the elapsed time before the required pressure is read on the pressure indicator 140 after the valve 92 is opened. The timer 102 may then be set for the determined calibrated time for the particular tube, diameter While one embodiment of the present invention has been considered in detail, it will be understood that other embodiments and modifications are contemplated by the inventors. It is the intention to include all embodiments and modifications as are defined by the appended claims within the scope of the invention.

What we claim as our invention is:

1. Structure for purging a tube or the like of air and filling the tube in combination with a plug for each end of the tube one of which includes a recess therein with gas under pressure, comprising tube purging apparatus including a source of gas under pressure, a tube purging tool connected to the source of gas and adapted to be inserted in one end of a tube for purging the tube before the plugs in combination with the tube are inserted in the ends of the tube, and tube pressurizing apparatus including a plug piercing and inserting tool connected to the source of gas having a portion extending into the recess in the one plug for inserting the one plug in the other end of the tube and passing the gas under pressure into the tube through the one plug with the other plug inserted in the one end of the tube.

2. Structure for purging and pressurizing a tube in combination with a plug for each end of the tube one of which includes a recess therein comprising tube purging apparatus adapted to be inserted in one end of the tube for purging the tube of air before the plugs are placed in the ends of the tube including a source of inert gas, a tube purging tool adapted to be inserted within the one end of the tube connected to the source of inert gas, a solenoid operated valve between the source of inert gas and tube purging tool, an electric circuit connected to the solenoid operated valve operable to actuate the valve on energization and a limit switch connected in the circuit operable to energize the circuit on insertion of the purging tool into the one end of the tube and tube pressurizing apparatus including a plug piercing and inserting tool for inserting the one of the plugs in the other end of said tube, piercing the plug and passing inert gas under pressure into the tube after the other plug is placed in the one end of the tube, a source of inert gas under pressure connected to the plug piercing and inserting tool, a solenoid operated valve between the plug piercing and inserting tool and the source of inert gas under pressure and an electric circuit for actuating the solenoid actuated valve and switch means operably associated with the plug piercing and inserting tool for actuating the electric circuit after piercing of the plug with the plug piercing and inserting tool.

3. Structure as set forth in claim 2 wherein the tube purging tool comprises an elongated, hollow cylindrical handle having a passage extending axially therethrough, a hollow cylindrical housing positioned over one end of the handle for telescopic movement with respect thereto, a point positioned over the other end of the housing having an opening extending therethrough, resilient means operable between the one end of the handle and said point for urging said housing outwardly of said one end of said handle and means operable between said handle and housing for permitting relative axial movement between the handle and housing and preventing the removal of said housing entirely from said handle.

4. Structure as set forth in claim 3 and further including a hollow cylindrical core secured in the passage extending through said handle and received in said opening through said point.

5. Structure as set forth in claim 2 wherein the plug piercing and inserting tool comprises an elongated, hollow cylindrical handle having a passage extending axially therethrough, a hollow cylindrical housing positioned over one end of the housing for telescopic movement with respect thereto, a point positioned over the other end of the housing having an opening extending therethrough, resilient means operable between the one end of the handle and said point for urging said housing outwardly of said one end of said handle, means operable between said handle and housing for permitting relative axial movement between the handle and housing and preventing the removal of said housing entirely from said handle and a hollow needle secured to the handle in communication with the passage through the handle and received in the opening through the point.

6. Structure as set forth in claim wherein the piercing tool point has a reduced diameter portion extending outwardly of the handle for fitting within the recess in the one plug to be inserted in the tube.

7. Structure as set forth in claim 5 and further including a chuck positioned within the housing around the opening therethrough adapted to grip the hollow needle to secure the needle to the housing on tightening of the chuck and means secured within the opening in the housing for tightening the chuck on the hollow needle.

8. Structure for filling a tube in combination with a plug for each end of the tube one of which includes a recess therein with nitrogen under a predetermined pressure comprising tube purging apparatus including a source of nitrogen under pressure, a tube purging tool including an elongated handle having a passage extending axially therethrough, a hollow cylindrical housing, one end of which is sleeved over one end of said handle, a purging tool point secured over the other end of said housing having an axial passage therethrough, a hollow core secured in the passage in the one end of the handle and extending into the opening through the point, resilient means operable between the one end of the handle and the point for urging the housing outwardly of the one end of the 'handle and means operable between the housing and handle for guiding the handle in relative longitudinal movement, a conduit connecting the other end of the handle to the source of nitrogen under pressure, a solenoid operated valve in said conduit, a source of electric energy, an electric circuit connected to the source of electric energy including a limit switch, a relay and a timer for actuating the valve for a predetermined time in response to closing of the limit switch and means connected between the housing and handle for actuating the limit switch on telescoping of the housing over the one end of the handle in response to placing the point of the purging tool over one end of the tube and moving the handle toward the point to insert the core into the tube, to purge the tube prior to inserting the plug-s 'in the ends of the tube and tube pressurizing apparatus for pressurizing the tube with nitrogen after the plugs have been inserted in the ends of the tube including a second source of nitrogen under pressure, a plug piercing and inserting tool, including an elongated handle having a passage extending axially therethrough, a hollow cylindrical housing one end of which extends over one end of the handle, a point secured over the other end of the housing having an axial opening extending therethrough and a reduced diameter outwardly of the handle adapted to be received in the recess in the second plug, resilient means acting between the handle and point for urging the housing outwardly of the one end of the handle, an elongated hollow needle extending through the passage in the handle and the opening through the point operable to pierce the plug with the point inserted in the recess in the one plug on movement of the handle toward the point, a resilient chuck positioned in the passage in the handle surrounding the needle and chuck tightening means within the passage in the 'handle for tightening the resilient chuck on the needle, a conduit connecting the plug piercing and inserting tool, and the second source of nitrogen under pressure, a second solenoid operated valve in the conduit connecting the plug piercing and inserting tool to the second source of nitrogen under pressure, a second source of electric energy and a second electric circuit including a second limit switch, relay and timer operable to energize the second solenoid operated valve for a predetermined time in response to actuation of the second limit switch, means for actuating the second limit switch on piercing of the one plug in the other end of the tube by the needle in response to movement of the handle of the piercing tool relative to the point thereof and pressure indicating apparatus for use in calibrating the sec.- ond timer to open said second solenoid operated valve for the exact time necessary to pressurize the tube to the desired pressure comprising a pressure gage, a third conduit connected to the pressure gage, a hollow needle connected to the third conduit and adapted to be inserted into the plug in the one end of the tube to record the pressure therein during pressurizing of said tube by said tube pressurizing apparatus.

9. A method of producing a hollow pressurized gas filled tube comprising passing gas under pressure into one end of the tube, to purge the tube of air, plugging the one end of the tube, plugging the other end of the tube, inserting a needle through the plug in the other end of the tube, pressurizing the tube with the gas through the needle and removing'the needle from the plug in the other end of the tube. I

10. A method as set forth in claim 9 and further including timing the introduction of gas into the one end of the tube to insure complete purging of air from the tube before the plugs are inserted therein.

11. A method as set forth in claim 9 and further including timing the pressurizing of the tube with the gas through the needle to insure predetermined pressure within said tube.

12. A method as set forth in claim 11 and turther including inserting a needle in the plug in the one end of the tube connected to a pressure gage to determine 'the time required for pressurizing the tube with the gas through the needle to bring the tube to a predetermined pressure.

13. A purging tool for purging air from a tube section or the like comprising an elongated hollow cylindrical handle having a passage extending axially therethrough, a hollow cylindrical housing one end of which is sleeved over one end of the handle for reciprocal axial telescopic movement with respect thereto, a point having a cylindrical portion extending into the other end of thethollow cylindrical housing and connected thereto and having an annular flange portion extending radially outwardly from the cylindrical portion outside of the one end of the housing and an opening extending through the point aligned with the passage in the handle, resilient means operable between the one end of the handle and the point for urging the housing outwardlyyof the one end of the handle and means operable between said handle and housing for permitting relative axial movement between the handle and housing and preventing the removal of said housing entirely from said handle and a hollow cylindrical core secured in one end of the passage extending through said handle and received in the opening through the point;

14. Structure as set forth in claim 13 and further including a source of gas under pressure, a conduit connecting the other end of the passage through the handle with the source of gas, a solenoid operated valve in said conduit, a source of electric energy, an electric circuit connected to the source of electric energy including a limit switch and a relay and a timer for actuating the valve for a predetermined time in response to closing of the limit switch and means connected between the housing and handle for actuating the limit switch on telescoping of the housing over the one end of the handle.

15. A plug piercing and inserting tool for use in apparatus for pressurizing a tube with gas in combination with a plug for each end of the tube one of which includes a recess therein comprising an elongatedhandle having a passage extending axially therethrough, a hollow cylin drical housing one end of which extends over one end of the handle for reciprocal axial telescopic movement relative thereto, a point secured over the other end of the housing having an axial opening extending therethrough and a reduced diameter outwardly of the handle adapted to -be received in the recess in the one plug to facilitate inserting the one plug in one end of the tube, resilient means acting between the handle and point 'for urging 8 the housing outwardly of the one end of the handle, an elongated hollow needle extending through the passage in the handle and the opening through the point operable to pierce the plug on movement of the handle toward the point, a resilient chuck positioned in the passage in the handle surrounding the needle and Chuck tightening means Within the passage in the handle for tightening the resilient chuck on the needle.

16. Structure as set forth in claim 1-5 and further including a source of gas under pressure, a conduit connecting the plug piercing and inserting tool and the source of gas under pressure, a solenoid operated Valve in conduit, :1 source of electric energy, an electric circuit including a limit switch, relay and timer operable to energize the solenoid operated valve for a predetermined time in response to actuation of the limit switch and means for actuating the limit switch on telescoping of the housing over the one end of the handle.

References flied UNETED STATES PATENTS Stockton 14l4 X Handelan 14-1383 X Hood.

Klein 14-1329 X Nelson et al.

Doyner 14-1333 X Le Clair 141329 X Price l41-329 X Dorsey et al 141-329 X LAVERNE D. GEIGER, Primary Examiner.

I ZQUSTON S. BELL, Examiner.