The element terminal holes in the furnace walls must be in line and be large enough in size to prevent the element or guide sleeve from being pinched at all furnace temperatures. Guide sleeves are optional but recommended for use with the SER and TSR elements and with fiber wall furnaces. Some furnaces have a potential problem of electrical conduction to ground. The ceramic guide sleeves have superior electrical resistance properties and can prevent this from occurring.
The sleeves protect the furnace wall insulation and provide a constant clearance. They also are recommended in applications where product vapors may condense in the furnace terminal holes. This can cause the element to stick to the wall. When sticking the element may break from mechanical forces caused by thermal expansion and contraction. The sleeves can prevent this from occurring, for if the element sticks to the sleeves, the sleeves can move.
When vapors depositing on the elements are a problem it is recommended that ceramic fiber pads be placed beneath the element cold ends and the guide sleeves where they enter the furnace.
Tucking ceramic fiber around the circumference of the element where it enters the terminal hole is also recommended to reduce heat losses from radiation and convection.
Standard Sizes
Guide sleeves are available for Starbar diameters 1/2" (13 mm) through 2-1/8" (54 mm) in a standard length of 4-1/8" (105 mm) and for 2-3/4" (70 mm) Starbars in a standard length of 5.5" (139 mm). Longer lengths available upon request.
Sizing Breakdown
| Item # | Starbar Nominal Dia. | Sleeve Outer Dia. | Sleeve Inner Dia. | Sleeve Overall Length | Collar Diameter | Collar Thickness |
|---|---|---|---|---|---|---|
| 2024-1 | 0.50 Inch 13 mm | 1.37 Inch 35 mm | 0.81 Inch 20 mm | 4.12 Inch 105 mm | 2.00 Inch 50 mm | 0.38 Inch 10 mm |
| 2024-1 | 0.63 Inch 16 mm | 1.37 Inch 35 mm | 0.81 Inch 20 mm | 4.12 Inch 105 mm | 2.00 Inch 50 mm | 0.38 Inch 10 mm |
| 2024-3 | 0.75 Inch 19 mm | 1.75 Inch 44 mm | 1.18 Inch 30 mm | 4.12 Inch 105 mm | 2.38 Inch 60 mm | 0.38 Inch 10 mm |
| 2024-3 | 0.88 Inch 22 mm | 1.75 Inch 44 mm | 1.18 Inch 30 mm | 4.12 Inch 105 mm | 2.38 Inch 60 mm | 0.38 Inch 10 mm |
| 2024-5 | 1.00 Inch 25 mm | 2 Inch 51 mm | 1.44 Inch 37 mm | 4.12 Inch 105 mm | 2.75 Inch 70 mm | 0.38 Inch 10 mm |
| 2024-5 | 1.25 Inch 32 mm | 2 Inch 51 mm | 1.44 Inch 37 mm | 4.12 Inch 105 mm | 2.75 Inch 70 mm | 0.38 Inch 10 mm |
| 2024-7 | 1.38 Inch 35 mm | 2.25 Inch 57 mm | 1.69 Inch 43 mm | 4.12 Inch 105 mm | 3 Inch 75 mm | 0.38 Inch 10 mm |
| 2024-7 | 1.50 Inch 38 mm | 2.25 Inch 57 mm | 1.69 Inch 43 mm | 4.12 Inch 105 mm | 3 Inch 75 mm | 0.38 Inch 10 mm |
| 2024-9 | 1.75 Inch 44 mm | 2.50 Inch 64 mm | 1.94 Inch 49 mm | 4.12 Inch 105 mm | 3.25 Inch 83 mm | 0.38 Inch 10 mm |
| 2024-11 | 2.12 Inch 54 mm | 3.00 Inch 76 mm | 2.44 Inch 62 mm | 4.12 Inch 105 mm | 3-75 Inch 95 mm | 0.38 Inch 10 mm |
| 2024-12 | 2.12 Inch 54 mm | 3.00 Inch 76 mm | 2.44 Inch 62 mm | 6.63 Inch 168 mm | 3-75 Inch 95 mm | 0.38 Inch 10 mm |
| 2024-15 | 2.75 Inch 70 mm | 4.00 Inch 100 mm | 3.25 Inch 83 mm | 5.50 Inch 139 mm | 5.00 Inch 127 mm | 0.63 Inch 16 mm |