TYPEDBDUMBBELLandTDBTUBULARDUMBBELL-(.docVIP

TYPE DB DUMBBELL and TDB TUBULAR DUMBBELL - (ENLARGED COLD END) – SILICON CARBIDE HEATING ELEMENTS DB哑铃型和TDB管状哑铃型（扩大冷端部）硅碳棒加热元件 GENERAL DESCRIPTION 概述 One of the earliest heating element designs, the enlarged cold ends of the Dumbbell style element were originally made oversized to increase cold end cross section, lowering electrical resistance, thereby lowering cold end operating temperature. Modern Dumbbell, by contrast, employ an advanced technology to keep the terminal ends cool by virtue of the decreased resistivity of the lower resistance cold end material used in the manufacturing process. Oversize cold ends are therefore no longer necessary. Non-dumbbell (RR) can be substituted for Dumbbell. Improvements in the cold-end-to-hot-zone resistance ratio between the original DB and new DB has been dramatic. The old style resistance ratio was 1:3, whereas the new DB and RR resistance ratio is a minimum of 1:15. 哑铃型硅碳棒是最早的加热元件之一，起初是制造的特别大来扩大冷端部的横截面，减少电阻，从而降低冷端部的操作温度。现在的哑铃型硅碳棒，与以往相比，在制造过程中，采用了比较先进的技术，冷端部材料依靠降低电阻系数来降低阻值，从而保证冷端部的凉度。这样就再没有必要制造特别大的冷端横截面了。DB型硅碳棒已经取代了以前的RR型硅碳棒。DB型硅碳棒的冷端部和发热部的电阻比已经发生了巨大的改进。以前的电阻比为1：3，但是现在的电阻比的最小值已经达到1：15。 The first several inches of the cold ends are metallized with aluminum to provide a low-resistance contact surface. Electrical connections are made using flat aluminum braids, held in compression to the cold end circumference by stainless steel spring clamps. 硅碳棒的冷端部的两端的接触面喷了少量铝来降低阻值。电路依靠喷铝部连接起来，用不锈钢弹簧夹子固定在冷端部的周围。 DB is described by giving the overall length, the heating section length, the hot zone outer diameter and the cold end outer diameter. As an example, DB 22 x 15 x .31/.50 is a Dumbbell 22 inches long, 15 inch hot zone, .31 hot zones OD and .50 cold ends OD. In millimeters the part number would be DB 560 x 380 x 8/14. For sizes available, please refer to Table B, DB Dimensions, and page 3. DB型硅碳棒的具体尺寸已经给出，总长度，发热部长度，发热部管的外径和冷端部管的外径。例如，DB 22 x 15 x .31/.50，指管的总长为22英寸，发热部长为15英寸，发热部的外径为0.31英寸，冷端部的外径为0.50英寸。用毫米表示零件号码为DB560 x