United States Patent
`
`1191
`
`[11]
`
`3,967,614
`
`Stroud
`1451 July 6,1976
`
`
`
`[54] GAS FIRED FUSION FURNACE AND
`FUSION HEAD ASSEMBLY
`
`[75 ]
`
`Inventor:
`
`Dale E. Stroud, Elyria, Ohio
`
`Primary Examiner—Carroll B. Dority, Jr.
`Attorney, Agent, or Firm—Polster and Polster
`
`[73] Assignee: Emerson Electric Co., St. Louis, Mo.
`
`[57]
`
`ABSTRACT
`
`[22] Filed:
`
`Jan. 2, 1975
`
`[21] Appl. No.: 538,187
`
`[52] US. Cl. .....................».......... 1 26/229; 236/15 B;
`'
`432/46; 432/49
`Int. Cl.2 ............................................ F24C 3/ 12
`[51]
`[58] Field of Search
`126/229, 230, 234, 343.5 A;
`236/15 BB, 7; 432/49, 46; 431/62
`
`[56]
`
`1,075,991
`1,294,504
`1,734,747
`1,855,551
`2,085,581
`2,106,505
`2,823,740
`3,314,411
`
`References Cited
`UNITED STATES PATENTS
`
`Ruud ...................................... 237/7
`10/1913
`..................... 431/329
`2/1919 Magee
`
`Seeley ...................... 126/3435 A
`11/1929
`Jackson.
`....................... 431/62
`4/1932
`
`6/1937 Greeh ................... 431/153
`
`1/1938 Morin.
`432/49
`
`2/1958 Morck....
`236/15 B
`Power ................................... 431/80
`4/1967
`
`In an assembly of fusion furnace and fusion head for
`applying heat to plastic pieces to be fused, the furnace
`being fired with gaseous fuel fed through a conduit to
`a burner head in the furnace from a source of fuel, a
`temperature sensing probe projects into the furnace.
`The temperature sensing probe is operatively con—
`nected to a gas flow control device in the conduit
`from the source to the burner. The flow control device
`acts to throttle the gas flow, to maintain a predeter~
`mined variably selective temperature of the probe,
`from a high pressure, high rate of flow of gas to a low
`rate of flow of gas to the burner head. A fusion head
`block has a well in it to receive the temperature sens-
`ing probe when the fusion head block is in a predeter-
`mined heat-receiving position with respect
`to the
`burner head, the well being spaced from the burner
`head. The burner head is provided with a wire screen
`to ensure the maintenanceof a flame at a reduced
`
`flow rate of the gaseous fuel.
`
`7 Claims, 12 Drawing Figures
`
`
`
`HONEYWELL - EXHIBIT 1023
`
`HONEYWELL - EXHIBIT 1023
`
`

`

`US. Patent
`
`July 6,1976.
`
`Sheet10f3
`
`3,967,614‘
`
`
`
` TEMPERATURE
`
`SENSOR
`
`
`FROM LPG BOTTLE
`
`FIG.4.
`38
`
`TEMPERATURE
`CONTROLLER
`
`

`

`US. Patent
`
`July 6, 1976
`
`Sheet 2 of3
`
`3,967,614
`
`_
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`

`3,967,614
`
`.1
`GAs FIRED FUSION FURNACE AND Fusion IIEAD
`ASSEMBLY
`‘
`'
`.
`
`BACKGROUND OF THE INVENTION
`
`10
`
`It has been common in the art of joining sections of
`heavy thermoplastic pipe in a so-called socket and
`saddle connection to heat a fusion head to a tempera-
`ture in excess of the softening temperature of the pipe
`and coupling, to press the fusion head onto the end of
`a pipe and inside the coupling to be joined, withdraw
`the head and insert the softened end of the pipe into the
`coupling, and inside wall of whichis also softened, to
`fuse them together. Fittings are similarly fused to pipe.
`Heretofore, the temperature of the fusion head has not .
`been controlled autbmatically In some heads, a ther-
`mometer has been provided by which the actual tem~
`perature of the head can be determined, but this has
`required that the operator remove the head from the
`fusion furnace at the appropriate time if the furnace is
`heated sufficiently, to provide satisfactory recovery
`time.
`One of the objects of this invention is to provide a
`fusion furnace and fusion head assembly by which the
`25
`headis heated quickly, and then maintained automati- ,
`cally at a desired temperature.
`.
`Another object15 to provide such an assembly which
`is reliable and safe.
`
`15
`.
`
`20
`
`. Other objects will become apparent to those skilled
`in the art in the light of the following description and
`accompanying drawing.
`SUMMARY OF THE INVENTION
`
`30
`
`.2
`assembly offusion furnace and fusion head of this in-
`vention;
`,
`,
`,
`.
`-
`1
`FIG. 21s a view in side elevation, partly broken away,
`of the left side of the device as viewedin FIG. 1 with a
`shroud and one embodiment of fushion head shownin
`broken lines;
`FIG. 31s a sectional view taken along the line 3—3 of
`FIG. 2;
`FIG. 4 is a connection diagram of elements of the
`furnace shown'in FIGS. 1-73;
`FIGS is an enlarged fragmentary view, partly in
`section and partly broken away of a burner head of the
`assembly of this invention;
`FIG 6!'1s a top plan viewof the burner head shownin
`FIG. 5;
`FIG. 7 is a view in edge elevation of a fusion head
`.block of this invention;
`FIG. 8 is aview in sideelevation of the fusion head
`block shown1n F.IG 7;
`FIG. 9IS asectional view taken along the line 9—9 of
`‘FIG. .7,
`FIG. 10 is a sectional view .taken alongthe line
`10—10 of FIG. 11;
`1
`1
`FIG. 11'1s abottomplan view ofanother embodiment
`of fusion head block; and ‘
`»
`w
`FIG. 12 is a connection diagram showing the ele-
`merits of another embodiment of fusion furnace part of
`an assembly of this invention, and their interconnec-
`"tion.
`
`,
`
`.
`
`,35
`
`40
`
`.45
`
`In accordance withthis invention, generally 'stated, in
`an assembly offusion furnace and fusion head'for ap-
`plying heat to plastic pieces to be fused, the furnace
`being fired with gaseous fuel conducted frOm a source
`to a burner head1n the furnace by means Of a gas sup-
`ply conduit, a, temperature sensing probe is provided
`which projects into the furnace; gasflow control means
`are operatively connected to the sensing probe and to
`the gas supply conduit for changing the flow rate of the
`gaseous fuel to the burner, and a fusion head block'15
`provided, having a well in it, receiving the temperature
`sensing probe when the fusion head block is in a prede-
`termined heat-receiving position with respect to the
`burner head. The well15 spaced from the burner head.
`In the preferred embodiment, the fusion head block
`is provided with at
`least one open ended passage
`50
`through it, one end of the passage having a burner head .
`receiving chamber, and the fusion head block passage
`is spaced from the probe-receiving well. The burner
`headis so positioned with respect to the block chamber
`that flame from the burner head projects into the block
`chamber. The burner head15 provided with a wire mesh
`screen to permit maintenance of a flame witha very
`10w gas flow.
`A safety thermocouple can be provided to shut off
`the flow of fuelIn case the flame should be accidentally
`extinguished.
`A tilt switch can also be provided to ensure that the
`flow of fuelis cutoffin case the furnace, which may be
`portable, is knocked over.
`1
`
`DESCRIPTION_OF THE PREFERRED
`EMBODIMENT
`Referring now to FIGS 1 through 9 of the drawings,
`for- one illustrative embodiment of fusion furnace and
`fusion head assembly of this invention, reference nu-
`meral 1 indicates the entire assembly. The assembly 1
`ineludesa fusion‘furnace 2 and a fusion head 5.
`In this embodiment, the fusion head 5 includes a
`quiOnhead‘block '50. The fusion head block 50, shOwn
`in FIGS 1 through 9, is generally circularin side eleva-
`tion, withtwo flat faces 51 and 52, provided With
`tapped bolf--receiving holes 53 by which interchange-
`able h'eat'er faCes; which complete the fusion head, are
`mountedin physical contact and heat transfer relation
`'to the block 50. The heater faces are standard and are
`neither illustrated nor do they fOrm a part of thisinven-
`tion.
`,
`The block 50is provided with an integral boss 54, the
`margins of which are defined by planes perpendicular
`to one another and tangent to the circIe of the rest of
`the head block, as shown particularly1n FIGS. 8 and 9.
`The lower edge sUrface of the boss 54 defines a flat
`base 55 for the fusionhea‘d bIOCk, and provides a body
`to accommodate a probe well 56, opening through the
`base 55 and clds‘ed at its inner end. The head block 50
`of this embodimentis made of aluminum, is of substan-
`I'tial thickness, and is provided with a two-branched
`passage 58 with openings 59 through an upper part of
`a side surface 60, and single chamber 61, communicat-
`ing with the paSSage 58 and opening throughthe base
`'
`, 55. A thermometer well 64 centered between openings
`59, extends radially inwardly to or slightly beyond the
`Center Of the circular portion of the block 50, perpen-
`dicularly to thebase 55. In this embodiment, the block
`his also provided with a pair ofpost or stanchion——receiv-
`ing seckets 65, extending chordally on an axis perpen-
`mdicular to the plane. of the base 55.
`
`55
`
`,60
`
`BRIEF DESCRIPTION OF THE DRAWING
`In the drawing,
`FIG 1 is a fragmentarytop planviewof oneembodi-
`merit of a fusion furnace part without a shroud, of an
`
`-65
`
`

`

`~ 3,967,614
`
`3
`In the embodiment shown in FIGS. 1 through 3,'the
`fusion furnace 2 includes a control box 3 and a furnace
`box or shroud 4. The control box 3 includes a top sup-
`porting wall 31, side walls 32, to which handles 33 are
`fastened, a back wall 34, a front wall 35, and a bottom
`wall 36.
`
`The shroud 4 includes a four-sided, open-topped
`boxing section 41, mounted on the top wall 31 of the
`control box by means of bolts extending through holes
`in the top wall 31 and into tapped pads 42 extending
`inwardly from the lower. part of the walls of the boxing
`section 41. The shroud 4 also includes cover members
`or lids 45, hinged on hinge members 43 on opposite
`side walls of the boxing section, as shown in FIG. 3. The.
`construction of the shroud is conventional.
`,
`The top wall '31 has four holes in it, two of Which are
`tapped to receive threaded shanks of stanchions 44.
`Another of the holes serves to admit a burner head 10
`
`of a burner 9, and the fourth hole to mount a probe 20.
`The burner 9 of this embodiment is a propane terch,
`such as is used in the plumbing trade, although burners
`adapted to use with other fuels, such as MAPP gas, for
`example, can also be used
`The stanchions 44, burner head 10 and probe 20 are
`sometimes described hereinafter as projecting into the
`furnace, by which is meantthat they project into the
`enclosure of the shroud 4, which is the heating area of
`the furnace
`The burner 9 is supported by a burner bracket 18
`mounted on the bottom wall 36, as shown1n FIG. 3.
`‘ The probe 20 is shown as being mounted in the top wall
`31 by means of nuts 21 and 22. In this embodiment, the
`fusion head block 50 is supported by the upper ends of
`the stanchions 44, engaging the closed upper ends of
`the sockets 65, and the top surface of the probe 20. In
`this position, the burner head 10 is located so the flame
`from the burner head projects into the chamber 61.
`The burner head 10 is cylindrical, with an open.
`mouth 11. An aspirating section 13. of the burner is
`conventional.
`
`Within the burner head and between the groove 12
`and the open mouth is a distributing plate 14 with a
`plurality of orifices 15 equispaced around and inboard
`of the edge of the plate 14. Between the plate 14 and
`the mouth 11'1s a screen 17, which, in the embediment
`shown, is stainless steel 16 mesh 0 02 diameter wire
`screen.
`'
`‘
`'
`
`10
`
`15
`
`20
`
`25
`
`30
`
`35
`
`40
`
`45
`
`4
`response to the reaching of the probe 20 of a tempera—
`ture to which the controller is set by setting of the knob
`37. Ordinarily, a burner of the type described will not
`function under low pressure, low flow conditions, ei-
`ther going out or blowing back. The provision of the
`mesh screen permits the burner to function both in its
`normal way at high pressure and high flow rates and
`also in a holding or pilot condition.
`In FIGS. 10 and 11, a different type of fusion head
`block 80 is illustrated. The fusion head block 80 is
`
`substantially rectangular in both side and edge eleva-
`tion. It is provided with a probe receiving well 86 and a
`thermometer receiving well 84, and, as distinguished
`from the two-branched passage of the embodiment
`shown in FIGS. 7-9, with a single passage 88, opening
`at 89 through an upper surface, and opening, through a
`burner head receiving chamber 81, through a lower
`surface of base 85. Stanchion accommodating channels
`87 are provided, ending1n a seat surface against which
`the ends of the stanchions 65 rest.
`In the operation of this embodiment, a propane gas
`tank is connected, by way of a shut off valve, pressure
`regulator, gas line and complementary quick connect
`fitting, to the quick connect fitting 39. The knob 37 is
`turned to the place at'which a pointer, not here shown,
`indicates the desired temperature. The propane tank
`shut-off valve is opened and the gas issuing from the
`burner head 10 is ignited. A fusion head is then placed
`on the probe 20 and stanchions 44, with the mouth of
`the burner 10 in the chamber 61, by means of handles,
`not here shown. The burner 9 operates at its optimum
`efficiency. because the gas being supplied it is at its
`usual high pressure and high rate of flow, thus heating
`the fusion head rapidly. When the predetermined tem-
`perature to which the flow contrOller 38 has been set is
`reached, the mercury in the temperature sensing probe
`20 acts to move a plunger within the temperature con—
`troller to throttle the flow of gas to the burner and
`reduce its pressure, to reduce the flame to a point at
`which the temperature of the fusion head is maintained
`constant, or decreases very slowly. In the latter case,
`the cooling of the fusion" head only a few degrees re-
`opens the flow controller quickly to restore the fusion
`head to its desired temperature Although it is not illus—
`tratedin FIGS 1—4, in this embodiment as in the em-
`bodiment described hereinafter, the size of the flame1n
`the pilot or by-pass condition can be controlled by a
`needle--type by-pass contained in the controller 38,
`which1s accessible through an opening in the front wall
`35.
`Referring now to FIG. 12, a more elaborate fusion
`furnace control system is illustrated diagrammatically.
`In this embodiment, a pressure regulator 70 and pres-
`suregage 71 are housed in the control box 3, with the
`pressure gage mounted in an ‘opening in the front wall
`35. An on-off solenoid type safety valve 72, in the gas
`line 26,
`is electrically connected to a mercury tilt
`switch 73 and a thermocouple 74 in immediate heat
`transfer relation to the‘ flame of the burner 9. The
`safety valve 72 has a button or plunger 77 which
`projects through an opening in the front wall 35. In the
`line 26 between the temperature controller 38 and the
`burner 9, a throttle valve 75 is also provided, with a
`plunger 79, shown schematically,
`to mechanically
`lower the flame size of the main flame when the covers
`45 are opened. By means of a needle valve 78’inside the
`control b0x, the size of the flame in the holding or pilot
`condition can be adjusted.
`
`
`
`Mounted to extend through the front wall 35 of the
`base housing 3 are a rotatable control knob 37 of a gas .
`50
`flow controller 38, and a quick-connect fitting 39. The
`gas flow controller 3818 also referred to as the tempera-
`ture contrOller, because the temperature to which the
`fusion head is heated is a function of the flow, of gase-
`ous fuel to the burner 10.
`'
`A gas line or conduit 26 is connected to communi-
`cate with the quick-connect fitting 39 and to one side
`of the flow controller 38, and from another side of the
`flow controller 38 to the ‘aspirating section Of the
`burner. A line filter 28,
`in the line 26 between the
`quick-connect fitting 39 and the flow controller 38'1s
`conventional.
`A tube 23 communicates With and connects the
`probe 20 and the flew controller 38. In the embedi-
`ment shown, the probe 20'1s a bulb containing mercury,
`the tube 23'1s a capillary tube and the flow controller'IS
`a standard “Partlow” Model No. 28' controller which
`has the characteristic of permitting adjustment to pro~
`vide throttling of a high pressure high flow of‘gas in
`
`55
`
`60
`
`65
`
`

`

`3,967,614
`
`6
`block having at least one open-ended passage there-
`through, one end of said passage having a burner head
`receiving chamber, and a well in said fusion head block
`receiving said temperature sensing probe when said
`fusion head block is mounted in said fusion furnace
`with the said burner head in said burner head receiving
`chamber, said well being spaced from, parallel to and
`physically separated from said burner head receiving
`chamber.
`2. The improvement of claim 1 wherein said temper-
`ature sensing probe comprises means acting at a prede-
`termined temperature for throttling said gas abruptly to
`a relatively low flow rate to provide a flame incapable ,
`of raising the temperature of said fusion head substan-
`tially above said predetermined temperature under
`normal ambient conditions.
`
`3. The improvement of claim 1 wherein the said
`burner head is provided with a mesh screen positioned
`on the mouth side of a distributing plate in said burner
`head.
`
`4. The improvement of claim 1 including a solenoid
`type safety valve in said gas supply conduit between
`said source and said burner, and thermocouple means
`in heat transfer relationship with flame at said burner
`head and electrically connected to said safety valve.
`5. The improvement of claim 4 wherein a tilt switch
`is electrically connected between said thermocouple
`and said safety switch, whereby tilting of said control
`box breaks electrical connection between the thermo—
`couple and said safety valve.
`»
`6. The improvement of claim 1, wherein said fusion
`furnace includes covers hinged to be opened and
`closed, and a throttle valve and plunger are mechani-
`cally associated with said covers to lower the flame
`when the covers are opened.
`7. The improvement of claim 6 including a needle
`valve for adjusting the size of flame in the lowered
`condition.
`*
`*
`>1:
`*
`*
`
`5
`The safety valve 72 operates in the usual way. De—
`pressing the button 77 in a pilot position opens a valve
`by a bypass line 76 which communicates through the
`needle valve 78 and the throttle valve 75 with the
`
`burner 9, which can then be lighted. Heating of the
`thermocouple 74 energizes the holding solenoid in the
`safety valve, after which the plunger button 77 can be
`released. Turning of the control knob on to position
`then opens the entire main gas line 26 from the quick-
`connect to the burner. If the flame at the burner is
`
`extinguished, cooling of the thermocouple reduces the
`current to the solenoid in the safety valve below the
`holding condition, and the valve closes. Similarly, if the
`furnace is tilted more than a predetermined angle from
`the horizontal, the mercury tilt switch opens, breaking
`the circuit from the thermocouple, and causing the
`solenoid to release the valve to close the safety valve.
`Numerous variations in the construction of the as-
`
`sembly of this invention, within the scope of the ap-
`pended claims, will occur to those skilled in the art in
`the light of the foregoing disclosure.
`Having thus described the invention, what is claimed
`and desired to be secured by Letters Patent is:
`1. In an assembly of fusion furnace and mountable
`and demountable fusion head for applying heat to plas-
`tic pieces to be fused, said fusion head including a
`fusion head block and said furnace being fired with
`gaseous fuel conducted, by means of a gas supply con-
`duit, from a source to a burner having a burner head
`projecting upwardly into said furnace, the improve-
`ment comprising a temperature sensing probe project-
`ing upwardly into said furnace parallel to said burner
`head, gas flow control means operatively connected to
`said temperature sensing probe and to said gas supply
`conduit for changing the flow rate of gaseous fuel to
`said burner from a rapid flow to a relatively low but
`continuous flow and vice versa, said low flow being
`insufficient to raise the temperature of said fusion head
`beyond a predetermined level; and said fusion head
`
`10
`
`15
`
`20
`
`25
`
`30
`
`35
`
`40
`
`45
`
`50
`
`60
`
`65
`
`

`

`Column 5,
`
`line 8, "knob on to position" should be
`
`"knob to on position".
`
`Signed and Scaled this
`
`Twenty-first Day of September 1976
`
`RUTHC.MASON
`
`Alresrmg Officer
`
`C.MARSHALLDANN
`
`UNITED STATES PATENT OFFICE
`
`CERTIFICATE OF CORRECTION
`
`Patent No.
`
`3,967,614
`
`Dated
`
`JUIY 6, 1976
`
`Invmunr(s)
`
`Dale E. Stroud
`
`It is certified that error appears in the above-identified patent
`and that said Letters Patent are hereby corrected as shown below:
`
`(‘ummissr‘um'r uj'Parenrs and Trademarks
`
`