Application of Roots blowers in pneumatic conveying systems

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This post was last edited by Beautiful mountains and clear waters_KJNI on 2018-10-19 at 15:52. I. Characteristics of pneumatic conveying systems: In modern factories, many enterprises make use of pneumatic conveying systems. Pneumatic conveying systems offer a large conveying capacity and high efficiency, making them the preferred choice for many enterprises. Pneumatic conveying devices can be divided into suction-type and pressure-type (positive pressure and negative pressure), among which Roots blowers are an essential component in such devices. Illustration: Negative pressure conveying system and positive pressure conveying system: http://www.shrizer.com/data/upload/image/20181017/1539760637311678.png http://www.shrizer.com/data/upload/image/20181017/1539760637975582.png II. Differences between positive pressure and negative pressure conveying: 1. Suction type: How it works: It is accomplished on the suction side of the ventilator ； Pressure condition: negative pressure, preventing materials and dust from escaping or floating around ； Characteristics of material transportation: Material is conveyed from multiple locations to one point; suitable for transporting materials over large areas or at low depths. The amount of material that can be transported and the distance it can be conveyed are limited ； Feeding method: Simple ； Requirements for the unloader: High air-tightness is required for the dust collector of the unloader ； 2. Pressurization type: How to accomplish it: The compression section of the ventilator is completed ； Pressure condition: Positive pressure, dust leakage ； Characteristics of material transport: long-distance, high-volume transfer from one location to multiple locations ； Feeding method: Complex; when the conveying pressure is high, the tank located at the upper part of the feeder needs to be designed as a sealed structure ； Requirements for the unloader: simple ； III. Troubleshooting of Roots blowers in pneumatic conveying: Fault symptoms, causes, and solutions
Motor overload: Increased resistance due to a clogged inlet filter or other reasons, resulting in negative pressure. Pressure increases even when the outlet pressure remains unchanged. The issue is resolved after inspection.
Increased pressure in the outlet system: Resolved after inspection.
Friction between stationary and moving parts: Adjust the clearance.
Damaged gears: Replace them.
Damaged bearings: Replace them.
Oil leakage: The oil level is too high, causing oil to leak from the drain port; lower the oil level. Sealing wear leading to oil leakage at the shaft ends: Replace the seals.
Blocked ventilation openings in the wall panels and oil tank, causing oil to leak into the casing: Clear the ventilation openings; install plugs with a certain diameter in the intermediate chamber, and open the plugs under the wall panels.
Pressure higher than specified: Reduce the pressure.
Excessively high temperature: Too much oil, too thick oil, or dirty oil in the tank; lower the oil level or remove some of the oil.
Clogged filters or pipes: Remove the obstructions.
Pressure higher than specified: Reduce the pressure difference across the blower.
Excessive wear of the impeller, resulting in large gaps: Repair the gaps.
Poor ventilation and high room temperature, leading to high inlet temperature: Install ventilation openings to lower the room temperature.
Too low operating speed, causing belt slippage: Increase the speed to prevent belt slippage.
Reduced air volume: Clogged inlet filter; remove dust and obstructions from the filter.
Excessive wear of the impeller, resulting in large gaps: Repair the gaps.
Belt slippage: Tighten the belt or increase the number of belts.
High inlet pressure loss: Adjust the inlet pressure to the specified value.
Ventilation leaks due to pipes: Inspect and repair the pipes.
Excessive vibration and noise: Bearing clearance exceeds the specified value or the bearing housing is damaged; replace the bearings or bearing housing.
Excessive gear backlash, misalignment, or poor fixation: Reinstall the gears and ensure proper alignment.
Impeller collisions caused by foreign objects and dust: Clean the blower and check for damage to the casing.
Impeller collisions due to overload or shaft deformation: Check the back pressure, ensure proper alignment of the impeller, and adjust the gaps.
Friction between the impeller and the casing inlet due to overheating: Check the filter and back pressure, and increase the gap between the impeller and the casing inlet.
Imbalance of the impeller due to deposits or foreign objects: Clean the impeller and casing to ensure proper working clearance.
Loose anchor bolts and other fasteners: Tighten the anchor bolts and level the base.
Motor overload: High pressure difference compared to the specified value, i.e., high back pressure or inlet pressure; reduce the pressure to the specified value.
Excessive fan flow compared to the requirements of the equipment, resulting in increased pressure: Release excess gas to the atmosphere or reduce the blower’s speed.
Clogged inlet filter or obstacles in the outlet pipes: Remove the obstacles.
Collisions and friction between rotating components: Stop the machine immediately and investigate the cause.
Too high oil level: Adjust the oil level to the correct level.
Overheating of narrow V-belts, excessive vibration, and small pulleys: Check the belt tension and replace them with pulleys of larger diameter.
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