Heating system for thermoforming
First Claim
1. Apparatus for distributing and regulating three phase electric power to a series of loads, comprising in combination:
- a. a relay series of solid state relays the number thereof being a whole integer evenly divisible by 3 and 8;
b. a load series providing one load for each of said solid state relays;
c. a three phase power source operatively connected to each of said solid state relays with each of said solid state relays receiving only one phase thereof; and
d. a central processing unit operatively connected to said relay series and adapted to (1) activate each of said solid state relays on a millisecond sequencing basis to supply power to each of said loads at a predetermined power level, (2) maximize repeat frequency for smooth power delivery, (3) substantially balance positive and negative half cycles and (4) keep all power cycles at least two half cycles long.
2 Assignments
0 Petitions
Accused Products
Abstract
A programmable computer-controlled fast response infrared heating system capable of precise individual zone control and especially useful for thermoforming of plastic sheets comprises an array of fast response quartz heaters on a platen, a terminal box having a CPU and mounted on and moving with the platen and which needs only one power line to it and which distributes the power to the heaters sequentially on a milli-second time basis with an essentially constant power output to each heater. The power is three phase and switching occurs only when the voltage over a relay is zero to minimize RFI/EMI emissions. The CPU is interfaced with a general purpose computer at the operator'"'"'s console and a touch activated display showing the percent of available power being supplied to each heater. The operator by touch command can change the percentage of applied power for any one heater or the total power supplied to the whole of the array. The need to use a heavy umbilical cord of a multiplicity of power lines to the heater platen is obviated.
36 Citations
12 Claims
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1. Apparatus for distributing and regulating three phase electric power to a series of loads, comprising in combination:
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a. a relay series of solid state relays the number thereof being a whole integer evenly divisible by 3 and 8; b. a load series providing one load for each of said solid state relays; c. a three phase power source operatively connected to each of said solid state relays with each of said solid state relays receiving only one phase thereof; and d. a central processing unit operatively connected to said relay series and adapted to (1) activate each of said solid state relays on a millisecond sequencing basis to supply power to each of said loads at a predetermined power level, (2) maximize repeat frequency for smooth power delivery, (3) substantially balance positive and negative half cycles and (4) keep all power cycles at least two half cycles long. - View Dependent Claims (2, 3)
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4. A heating system comprising:
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a heater having a series of individual electric heating elements on a support;
said series being arranged in an array of zones;the following being carried by said support, i. a power control board having a series of solid state relays, one for each said zone with each relay being electrically connected to supply power to one of said zones; ii. a first computer actively connected to said power control board to individually turn each of said solid state relays on and off; a power cable to said power control board connecting to each of said solid state relays and adapted to supply three phase power thereto with only one phase thereof being supplied to any one solid state relay; and a control console remote from said support and comprising; i. a second computer interfaced with said first computer and adapted to command the amount of power to be supplied to each said zone through said first computer by controlling the amount of times each of said relays will be on and off; ii. a computer program operating said second computer; and iii. a touch activated display interacting with said second computer and computer program displaying for each said zone of said array the amount of power being supplied to that zone, said first computer and said second computer operating digitally on a millisecond time basis to operate sequentially each said solid state relays and thus provide essentially constant power output to each of said zones. - View Dependent Claims (5, 6, 7, 8, 9, 10, 11, 12)
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Specification