Drying machine bag filter

The bag filter of the dryer is a new type of bag filter designed based on the characteristics of the dryer flue gas, combined with theory and practice. The bag filter of the dryer has different research and design from other types of bag filters.

The bag filter of the dryer adopts a self-developed "lifting switching valve" and "combination state" for dust cleaning.

Characteristics of bag filter for dryer:

1. Reduce the volume, weight, and cost of dust removal equipment;

2. Simple operation, low operation and maintenance costs, and smooth operation;

3. Compact design and reasonable structure.

The bag filter of the dryer has small air leakage and can clean adjacent small compartments during dust removal; No issues of "secondary dust" and "dust reattachment"; Compact structure and light weight; Box structure design, easy to assemble on site; The advantages of dust removal filter bags include long service life. The characteristics of its equipment are:

Filtering condition: Adopting a combination structure of blocking and filtering dual dust removal mechanisms. The dusty flue gas enters the filter bag in the filtering chamber through the air inlet duct above the ash hopper. A guide plate is installed in the air inlet duct, and coarse dust particles fall into the ash hopper under the obstruction of the guide plate and the action of gravity, achieving pre separation of dust and reducing the wear of the filter bag by dust. Fine dust flows into the filter bag with the airflow, and the dust is trapped on the filter bag. The airflow is purified through the dust removal bag, and the purified airflow is discharged into the atmosphere through the induced draft fan.

Dust cleaning condition: Only one lifting switching valve is used to replace other types of dryer bag filters. One bag chamber requires a ventilation butterfly valve and a reverse blowing butterfly valve to operate simultaneously to complete the reverse blowing dust cleaning work, making it easy to achieve a "combined state" dust cleaning control process and achieving ideal dust cleaning effect.

Design scheme of bag filter for dryer:

The bag filter of the dryer mainly adopts the following process design technical solutions in practical applications:

1. Design of ventilation and dust removal system for dryer tail

In the design, a bag filter with a dryer is used for dust removal, which not only simplifies the process flow and reduces system resistance, but also reduces air leakage in the system.

2. Working temperature

The allowable high temperature for the bag filter of the dryer is ≤ 180 ℃. Smoke above this temperature shall not directly enter the dust collector. The "cold air valve" installed on the inlet duct shall be used to mix with the atmosphere for cooling measures, and the smoke temperature shall be automatically adjusted.

3. Selection of anti condensation filter material

Our company's fiberglass filter material has been treated, and its hydrophobicity, flexural resistance, and other properties have been significantly improved. It has excellent anti condensation performance, especially bending resistance, which is several times higher than that of plain glass fiber filter material, low resistance, dust removal, and stability. Our company's fiberglass filter material has no obvious stripes on the surface, and the fabric is smooth and flat, making it easy to clean dust. It is an ideal filter material for filtering wet and sticky dust and is suitable for use in drying machine flue gas dust removal.

4. Filter wind speed

The filtration wind speed (m/min) refers to the air flow rate passing through a unit area of filter cloth per unit time, that is, the air to cloth ratio (m3/m2 · min). The filtering wind speed not only determines the size of the dust collector, but also has a decisive impact on dust removal efficiency, dust collector resistance, cleaning effect, filter bag life, etc. For the dust collector to operate stably with low resistance, the filtration speed of fiberglass filter material is generally selected to be<0.5m/min.

5. Anti condensation technical measures

The intake pipe, shell, and ash hopper of the dust collector are all insulated to reduce the heat dissipation of the shell, and the insulation layer is also conducive to the heat storage of the equipment. Practical use has proven that this measure reduces the temperature difference between the inlet and outlet of the bag filter, achieving the expected insulation effect.

6. Microcomputer automatic control system

The key to bag filter is dust cleaning, and the quality of dust cleaning is related to the dust cleaning control mechanism. Our microcomputer control cabinet has been proven in long-term production practice to be easy to use and adjust parameters, ensuring the normal operation of bag filter.

Installation and maintenance of bag filter for dryer:

1. The bag filter of the dryer is a fully steel structure shell, therefore, it is strictly installed and accepted according to the design drawings;

2. The connection between the intake pipe, exhaust pipe, various valves, screw conveyor, etc. and the equipment should use packing, and the entire dust removal equipment system should have its airtightness;

3. The bundling of filter bags and the installation of filter bags should pay attention to quality. During the transportation process, special care should be taken to prevent the filter bags from coming into contact with surrounding hard or sharp objects. It is strictly prohibited to step on, press, or fold the bags to prevent holes and cracks in the filter bags from affecting the dust removal effect;

4. During the operation of the dust collector, the emission situation should be monitored at all times. If ash is found in the chimney, it indicates a short circuit in the flue gas, and the cause should be identified. If the filter bag is damaged, it should be replaced with a new one;

5. When the dust collector is operating normally and the filter bag is changed in different rooms, it is necessary to strictly follow the operating procedures and have a supervisor to prevent accidents from occurring;

6. Before the induced draft fan of the dust collector stops running, clean the dust on the filter bag and exhaust the dust in the ash hopper to prevent dust from drying up in the filter bag and dust hopper after shutdown, which may affect the dust removal efficiency and equipment service life.

Maintenance and precautions for bag filter of dryer:

1. Cylinders, conveyors, and induced draft fans should be inspected and refueled regularly, 1-2 times a week. Pneumatic triplets, air compressors, and air bags should be refueled and drained frequently, once per shift.

2. During the normal operation of the dust collector, the operator should monitor the inlet and outlet temperatures of the dust collector and the current of the main fan, and make records, usually every half hour.

3. Management of dust collector shutdown, startup, and shutdown process.

4. Cylinders, solenoid valves, electrical components, motors, and control cabinets should be cleaned.

5. When operating manually, remember to unload the ash first and then clean it.

6. Regularly check the sealing condition of cylinders, solenoid valves, flange surfaces, and maintenance doors. If any leaks or aging sealing strips are found, they should be replaced in a timely manner.

7. Regularly inspect the pneumatic system and ash discharge work, identify any abnormalities, and promptly eliminate the cause.