Patent GB-1345238-A (GB)
Title: Apparatus for and method of producing all-glass multiple sheet glazing units
IPC: C03B23/24
Filed: 1971-07-01
Abstract: 1345238 Multiple glazing units LIBBEYOWENS-FORD CO 1 July 1971 [6 July 1970] 30808/71 Heading C1M Apparatus for producing multiple glazing units by sealing together spaced glass sheets 20, 21 includes vacuum platens 65, 66 for supporting the sheets in face-to-face relation, means 31 for moving the platens along a path, a sealing assembly 38 including burner for sealing the sheet edges together, piston-rod 47 for moving the sealing assembly toward and away from the path, and mounted on the sealing assembly on one side of the path, a means 89 for passing a fluid medium across the path and mounted on the sealing assembly 38 on the other side of the path a transducer 114 for converting the received fluid pressure into electrical signals, the signal operating to move the sealing assembly towards or away from the path. In use, when a bar 157 on the means 31 operated a switch 156, solenoid valves 148, 152 allow communication between a piston and cylinder device 48, 49 on the piston-rod 47 of which the sealing assembly 38 is mounted, and a valve 144 which is in turn connected to a source and drain of hydraulic fluid. Consequently, the assembly 38 rises, since full air pressure is acting on the transducer 114 transmit a voltage which is larger than an opposing voltage produced by a potentiometer so that a signal is passed through demodulator 127 and amplifier 130 to activate a torque motor 143 associated with the valve 144 so as to raise the assembly. The assembly 38 rises until the interruption of the air flow by the glass sheets 20, 21 reduces the pressure acting on the transducer so that its output voltage is identical to the potentiometer output and a zero voltage is thus presented to the amplifier causing the motor 143 to idle and the assembly 38 to remain still. Should the assembly rise too high the pressure acting on the transducer 114 and therefore its output is further reduced, resulting in a voltage of opposite polarity being presented to the amplifier and causing the torque motor to act to lower the assembly 38. As the means 31 continue to move, the bar 157 operates a second switch 158 which closes the valves 148, 152 and also a time relay 175 which after allowing a time for the glass sheets to pass, activates a valve 178 which allows the piston 48 and thereby the assembly 38, to return to their initial position. The potentiometers may be adjusted to raise or lower the assembly when valves 148, 152 are open or to adjust the raised position of the assembly. To accommodate different sizes of sheet a manually operated twoway switch 183 is provided which is connected to the valve 178 to adjust the initial position of the assembly 38. The transducer 114 comprises a chamber 112  communicating with a fluid receiving means and closed by a flexible diaphragm 113, an armature 116 connected to the diaphragm and a coil 117 with a primary side connected to a source of power and a secondary side having a signal output. The means for passing the fluid across the path includes a supply pipe 89, which is passed through a coiled section 93 so that the incoming air is heated to a point at which it does not cool the glass being sealed, and a slotlike discharge orifice 107. The orifice 107 is aligned with but narrower than a slot-like receiving orifice 108 which communicates with a conduit 90 leading to the transducer 114. The orifices 107, 108 are mounted on opposed legs 81 of a block 84 which also includes a passageway 195, 201, 196 which delivers air to the orifice 108 to keep it clear of obstruction.