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The manifold on this Heatec HC heater connects to four independent hot oil circuits, each with its own side pump. Independent circuits provide more operating options than single circuits. When water is detected it should be purged from the system. This can take from two hours to two days or longer, resulting in downtime for the heater. The purge time depends on the amount of heat transfer oil in the system, the amount of water in the oil, and how the piping system is designed. How Does Water Get In? The expansion tank accommodates expansion and contraction of heat transfer oil during normal operation of the heating system. The tank is partially filled with heat transfer oil and is vented to the atmosphere (the unfilled space in the tank consists of air). As the heat transfer oil cools, it contracts and draws in fresh air. The cooling process causes moisture in the air to condense into water, which collects in the heat transfer oil and eventually moves into the heating circuit. Purging the Water Heatec HC or HCS heaters are designed to facilitate purging If you increase the temperatures in increments in excess of 10 degrees, the expansion tank may boil over. It is also important to make sure all the steam has exited the overflow/vent pipe to prevent the expansion tank from boiling over. water from the hot oil system. The most effective way to remove the water from their system is convert it to steam in the expansion tank and allow it to escape into the atmosphere. But this process must be confined to the expansion tank while avoiding the creation of steam in the circulating system. It requires careful manipulation of oil temperature and pressure. The process of purging water from the system includes several steps that require the resetting of valves on the heater to reroute the return fluid directly through the expansion tank. Since air in the expansion tank is constantly at atmospheric pressure, a temperature of 212 degrees Fahrenheit is all that is needed to change water into steam so it can escape through the overflow/ vent pipe. It is important to create and maintain a back pressure by adjusting the valve at the inlet of the expansion tank to restrict the flow of the fluid diverted into the tank. When doing so, be aware that increasing system pressure beyond its usual operating pressure can rupture worn parts. Always start cold and heat the oil slowly in increments of 10 degrees to allow the water to boil out progressively. Failure to do so may create a violent reaction in the expansion tank as the waterladen heat transfer oil enters the tank and its pressure drops suddenly due to atmospheric pressure. Preventive Maintenance Routinely purging water from the hot oil heating system should be part of the preventive maintenance plan. By keeping the system in good working order, the heater will last longer and cost less to operate. FOR MORE INFORMATION about purging water from hot oil systems at HMA plants, call Heatec Service Manager Ron Henry 800-235-5200 Fax: 423-821-7673 • E-mail: rhenry@heatec.com HOT-MIX MAGAZINE 32 VOLUME 16 NUMBER 1
green. Like mother-naturehits-the-Lotto green. It’s nice when the environmentally responsible thing and the profitable thing are one in the same. That’s exactly what being FRAP Ready brings to your operation. By incorporating a high percentage of Fractionated Reclaimed Asphalt Pavement into your mix, you will: Reduce the amount of virgin rock mined, use less oil, decrease the energy used for processing, conserve the energy used for trucking and lessen the pollution and CO produced at each step of the process. Oh, and you’ll also make money. Lots of it. The advantages of a FRAP Ready operation go well beyond being green. Use our online calculator at www.beFRAPready.com to learn what being FRAP Ready can mean to your operation. The ProSizer 2612V Calculate just how much you can save at beFRAPready.com. Call 800.545.2125 or contact your KPI-JCI or Astec Mobile Screens dealer to learn more.
Page 1 and 2: NEW! see the redesigned website for
Page 3: 16 20 VOLUME 16 NUMBER 1 Copyright
Page 6 and 7: ASTEC IND F A M I L Y O F MARCH 22-
Page 8 and 9: ASTEC IND F A M I L Y O F MARCH 22-
Page 10 and 11: Geared for High Production Plant in
Page 12 and 13: EXCELLENCE IN WORKMANSHIP Asphalt c
Page 14: sections of kiln chain attached to
Page 17 and 18: FOR BOB WAGNER, president of Blackt
Page 19 and 20: BUILT TO LAST THERE’S A SAYING,
Page 21 and 22: WHETHER THE PROJECT involves work o
Page 23: Upgrading to Handle TEXAS IS HOME T
Page 27 and 28: “There’s three inches of milled
Page 30 and 31: Purging Water From Hot Oil Systems
Page 34 and 35: Dealer and Customer Showcase the Ca
Page 36 and 37: Proactive: Take the Lead to Improve
Page 38 and 39: Astec Technology Delivers Solutions
Page 40: President Mario Huerta’s operatio
Page 43 and 44: NEWS Astec Traveled to Bauma China
Page 45 and 46: NEWS French and Spanish Spoken Here

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