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P.O. Box 110 • 105 Elwood Ave. • Medina, NY 14103 • Ph. (585) 798-4300 • 1-800-836-0754 • Email: info@antechsales.com
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Case Study #1 - Pressure & Temperature Cure Applications
Case Study #2 - Enhanced Safety and Automation for Injection Molder Case Study #3 - Rack Mount Furnace Control System Case Study #4 - Improved Coating on Screening Process Case Study #5 - Urethane Molding Line |
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CASE HISTORY #1
Pressure & Temperature Cure Application
Problem: The parts cure at 275 degree F with a chamber pressure of 100 PSI. Pressure must reach 100 PSI before introducing heat. A simple ramp and soak profile followed by a cool down and purge (release pressure), completes the curing process. A heat exchange circulation thermal fluid allows for cooling. Tubular heaters producing 30 kW at 240 volts, 3 phases were required for heating. Compressed air pressurizes the vessel. Solution: A Watlow Series 97A1-DDDD-00RG was selected to control pressure. Output 1 actuates a solenoid valve to turn on inlet air (pressurize). Output 2 actuates an outlet solenoid valve (depressurize). Output 3 is configured as a high alarm to indicate overpressure. When set point pressure is achieved, output 4 configured as an event signals the temperature controller to start a profile. A digital input on the 96 is signaled from the temperature controller when the chamber is to be depressurized. A Watlow Series 982C-25CD-JEGR was selected to control temperature. Output 1 drives solid state relays to control the heaters. Output 2 energizes a motor starter to pump coolant through the heat exchanger for the cool down sequence. An alarm on output 3 indicates over temperature. Output 4 is configured to signal the Series 96 control to reduce the pressure setpoint to zero and purge the pressure vessel. The second digital event input to the 982 disables the controller if the chamber door interlock switch is open. A Watlow Series 142 provides a safety limit against over temperature and controls a shutdown contactor. The process is initiated with a power switch. After a complete cycle, the 982 is programmed to go into a hold mode. Cycling power after the chamber is reloaded starts the cycle over again. The chamber has a mechanical pressure safety switch to prevent the chamber from being opened under pressure. Written by David Kozody, Antech Sales, Inc. CASE HISTORY #2
Problem: Sample pellets from a molded part require opacity testing. This process was dependent on manual labor for each step. The sample is placed on a cool platen and then the platen is heated to 125 degrees C (260 degrees F). There is also an upper platen, above the sample, heated to 125 degrees C (260 degrees F). Watlow FIREROD cartridge heaters and thermocouples accomplish this heating. (Antech Sales had built the two zone control panels that house the Series 935 controllers). Once the platen reaches set point, a manually activated ram drives the top platen down and flattens the pellet. After a brief dwell, cooling air is turned on until the platens cool to about 40 degrees C (100 degrees F). The ram retracts and the sample is removed for testing. Solution: Antech provided a solution to their customer's problem by suggesting a Watlow F4P controller. As the process was a basic dual channel temperature control profile with a small amount of I/O, Watlow's F4 controller fit nicely and eliminated the need for a PLC. Antech framed the profile and specified a F4DH-CACA-01RG. The F4 controller's I/O would handle the door interlock, ram activation, cooling air, start signal and off signal. This process improves the cycle and throughput for the application. Written by David Kozody, Antech Sales, Inc.
Problem: The full load to be controlled was 450 amps at 4.6 volts DC. Requirements included soft start, current limit, segment programming capability, computer integration, local digital indication of temperature and 0-10 VDC load voltage. DC power was requested to reduce RFI (electrical noise) potential in the lab. Commercially available power supplies did not offer all the required features. Solution: To solve the problem, a Eurotherm series 2408 control was integrated with a high current power supply from Lamda EMI. The 2408 control provided a P.I.D. control interface, digital indication of temperature, segment programming and EIA 485 interface for computer integration. The Lamda power supply allowed for 208 VAC input with 0 - 10 VDC load output. It also provided digital indication of voltage and current and a variable current limit. Antech provided the solution with design concept, engineering schematics and all required materials. The system was installed into a convenient rack mount case. Written by Carl Benz @ Antech Sales, Inc.
Problem: Customer places large grid coated in plastisol inside of press consisting of 2 large heated presses to manufacture screens of varying mesh classes. Due to lack of uniformity along heated platen the plastisol flows more freely in some areas than others and mesh screen does not bond evenly to grid. This causes the screen to fail quickly in the field and results in a large scrap rate. Solution: Antech adds additional zones of heating and limit control to the existing system. Three (3) zones of heat only control is increased to ten (10) zones of heat and overtemp control, per platen. Antech replaces mercury displacement relays with advanced SCRs to improve response time to temperature changes in platen. Thermocouples were placed strategically so that the best profiling of platen could be accomplished with the minimum amount of machining. Results: Customer reports scrap rate to be near zero and uniformity has been drastically improved and verified through thermal imaging camera. Payback on upgrades was less than 2 weeks and system has been working without heater or other component replacement for several years. Written by Kevin Yaeger, Antech Sales, Inc. CASE HISTORY #5
Problem: Current heater design does not effectively control and maintain temperature on large holding tank and along transfer lines to product pouring spigot. Results of uneven heating in current assembly produced discoloration and air bubbles in pour that produced inferior product. Solution: Antech custom designed heaters to wrap around holding tank with both temperature and high limit control. Additional heated zone was added to the bottom of the tank where valve was heated to prevent thermal losses at valve point. The heat traced transfer lines were replaced with a high pressure heated hose with dual thermocouples for process and high limit control to ensure more uniformity along the transfer lines. Additional heated zone was added to pump housing to make up for losses from previously unheated pump. Results: Product quality was improved far beyond customer expectations allowing larger molds to be poured without the discoloration or air bubbling effects that limited them to smaller molds in the past. Written by Kevin Yaeger, Antech Sales, Inc. |
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Opportunity: An autoclave manufacturer has designed a chamber to cure composite parts. The parts must be cured at a controlled pressure and temperature.
Opportunity: An injection-molding customer wanted to eliminate the discrete components and manual procedures in their manufacturing process. The customer also wanted to enhance the safety of their equipment by adding a door interlock device to prevent access to hot platens and moving parts.
Opportunity: A laboratory at a major university required a power supply for a tungsten resistance furnace.
Opportunity: Customer assembles screens for sorting processes using a plastisol coating on a fine mesh screen.
Opportunity: Customer requires better uniformity on urethane holding tank and transfer lines while pumping urethane into molds for custom manufactured parts. Customer was currently using silicone rubber heaters and heat trace to keep product at temperature.