Vacuum Sizing And Cooling Tank
Vacuum sizing and cooling tanks form part of the cooling and calibration section of precision single-screw extrusion lines. When the extruded tube enters the sizing sleeve, a vacuum pump removes air from the sealed chamber and creates negative pressure, which draws the tube wall outward against the sleeve. The cooling water removes the heat while the tubing remains pressed against the sizing sleeve, so it hardens at the correct diameter and retains a round cross-section. It also relieves internal stress before the tubing reaches the haul-off, which reduces the risk of collapse or shrinkage as it is pulled forward.
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Technical Specifications
| Parameter | Vacuum Sizing and Cooling Tank |
| Tube Size | Φ2–Φ25 mm or Φ3–Φ30 mm, adjustable as required |
| Tank Length | 3 / 4 / 6 m, with customizable modular lengths |
| Vacuum Pressure | −20 to −80 kPa |
| Motor Power | 1.5–3 kW for the vacuum pump and circulating-water pump |
| Material | SUS304 stainless steel |
| Control Method | Automatic vacuum adjustment and water temperature control |
| Number of Sections | 2–3 sections for pre-cooling, sizing, and cooling |
| Suitable Tubing | Precision medical tubing and small-diameter tubing |
Features
- Servo-controlled guide wheels carry the tubing through a multi-pass cooling path inside the tank and operate in sync with the haul-off motor. This provides enough cooling time in a smaller space and prevents tubing made from highly elastic materials from stretching out of shape.
- The vacuum pump is mounted separately from the tank to keep its vibration from affecting the stability of the extrusion process.
- The cooling tank has clear acrylic or tempered-glass covers along its structure, so operators can observe the tubing throughout the sizing and cooling process.
- Siemens digital vacuum controls work with a proportional pressure-control valve to adjust the negative pressure according to real-time readings. Consistent vacuum pressure prevents pulsations inside the tank and maintains tube roundness and a uniform outer diameter.
- Designed with swivel casters to move the cooling and sizing tank easily around the workshop. The tank exterior is made of SUS304 stainless steel, with SUS316 available upon request.
- Optional heat exchangers and filtration units can be added to the cooling tank. During long extrusion runs, the heat exchanger prevents rising circulating-water temperatures from causing abnormal tube shrinkage, while the filter keeps foreign matter from blocking the small holes in the sizing sleeve.
- The mounting frame has three-dimensional electric positioning and includes handwheels at the front and rear to allow for precise manual adjustment. During the extrusion process, the operators are able to adjust the concentric alignment between the sizing sleeve and the extrusion die opening, thus avoiding eccentricity that might otherwise lead to an uneven wall thickness.