Common Issues with Starch Vacuum Dehydrators in Potato and Cassava Starch Processing Equipment

Common Issues with Starch Vacuum Dehydrators in Potato and Cassava Starch Processing Equipment

Detailed descriptions and solutions for common issues with starch vacuum dehydrators in potato and cassava starch processing.

The starch vacuum dehydrator (also commonly referred to as a vacuum drum dehydrator) is a critical piece of equipment for moisture removal in starch processing. Common issues primarily revolve around

the vacuum system, filter cloths (filter belts), mechanical operation, and process procedures.

I. Abnormal Vacuum Level Issues

Vacuum level is central to the dewatering machine’s operation and directly determines the dewatering effectiveness.

1.  Low vacuum level or inability to establish vacuum: The dewatered starch is soft and wet, with a significantly high moisture content; it fails to hold its shape and releases water when squeezed.

Causes and Solutions:

System Leaks: This is the most common cause. Inspect all connections—including the vacuum chamber, pipes, and flanges—for leaks. Aged gaskets or loose bolts can allow air to be drawn in, disrupting the vacuum.

Damaged Filter Cloth: Large holes or severe delamination in the filter cloth allow large amounts of air to be drawn in directly, preventing the vacuum level from rising. The filter cloth must be repaired or replaced.

Blockage or leakage in the filtrate system: Leaks in the main or branch filtrate lines can also affect the overall vacuum level.

Vacuum pump failure: Problems with the vacuum pump itself, such as impeller wear, insufficient seal water, or inadequate motor speed, can lead to reduced pumping capacity.

2.  Excessively High Vacuum or Abnormal Fluctuations

Symptoms: The vacuum gauge displays abnormally high readings, which may even cause the equipment to shut down.

Causes and Solutions:

 Clogged demister or gas-liquid separator: These components are used to separate air and moisture. If clogged, they obstruct gas discharge, causing increased back pressure at the vacuum pump outlet, which manifests as abnormal vacuum levels. Shut down the equipment and clean these components.

Severe clogging of the filter cloth: The pores of the filter cloth are blocked by fine starch particles or impurities, resulting in extremely poor air permeability. Although the vacuum gauge shows a high reading, the actual dehydration efficiency is very low, and moisture cannot be effectively removed.