FAQ

For custom square-to-round transitions, provide the length and width of the rectangular end, diameter of the round end, flange standards and hole positions, transition length or available installation space, airflow direction (square-in-round-out or round-in-square-out), and installation orientation (whether eccentric or offset for square and round ends). Also specify plate thickness and fire resistance requirements. When paired with a fan, it's advisable to provide fan interface drawings and on-site pipe connection direction to ensure smooth alignment. Indicate the orientation of the rectangular long side and installation angle to avoid misalignment due to incorrect face direction, preventing on-site connection issues. If the cross-sectional areas at both ends differ, note the control end dimensions or provide a recommended flow rate. Complete parameters and clear drawings enable the manufacturer to accurately perform cutting and one-piece forming, reducing rework caused by dimensional mismatches.

An increase in packing bed pressure drop is usually caused by dust, crystals, or biological sludge blocking the spheres and voids, or by fouling of the hold-down plate above the bed and the mist eliminator section, which narrows the gas passages. First, strengthen circulating liquid filtration and upstream dust removal and mist elimination at the source to reduce impurities entering the packing; during operation, periodically increase the spray rate to flush the bed and wash off surface deposits. After shutdown, flush each layer from top to bottom with high-pressure water through the manway; if necessary, remove the spheres for cleaning and sieving outside the tower, discard broken, deformed, and heavily scaled spheres, and replenish an equal quantity of new spheres. Crystallized soluble salts can be removed by circulation cleaning with a dilute acid or dilute alkali compatible with the packing material and the process medium, followed by thorough rinsing with clean water. After treatment, re-load the packing uniformly and level it according to specifications, and reinstall the hold-down plate; the pressure drop can generally be significantly restored. If the pressure drop remains high after cleaning, the packing has aged or become cemented, and the entire layer should be replaced.

The holes of the punched plastic plate, which is processed according to specifications, undergo deburring treatment, resulting in smooth edges, no burrs, and no cracks. Under normal loading, it will not scratch the plastic filler or filter bag. If burrs, curling, or micro-cracks are present on the hole edges after punching, each piece should be inspected before loading the filler and leveled using sandpaper or a scraper. If necessary, defective plates should be removed. The edges and corners of the plates after cutting and splicing should also be chamfered to avoid sharp edges from tearing the filter bag, filter cloth, or injuring operators. When used for supporting bulk fillers, the smooth hole edges can also reduce wear between spheres and rings during loading and agitation. Upon receipt, check the flatness of the plate surface, the condition of the hole edges, and the edge treatment. If batches with concentrated burrs are found, promptly return or rework them. As long as the processing and inspection are properly executed, the multi-hole plate will not cause abnormal damage when in long-term contact with the filler.

Yes. Closed valves are usually marked with airflow direction or valve disc closing direction; correct orientation helps the pipeline pressure to push the disc toward the seat, enhancing the seal; reverse installation may push the disc away from the seat with pressure, increasing air leakage. The valve stem should be installed horizontally to avoid the disc's self-weight affecting the seal and operation. Centering the valve body ends and evenly tightening the flanges ensures that additional pipeline stress does not deform the valve body and seat or cause uneven seal surface contact. A full-closure air leakage check should be performed after installation, not just relying on actuator position signals.

There are directional requirements. Although concentric reducers have symmetrical shapes at both ends, it is necessary to distinguish the large end and small end: the large end should connect to the incoming flow direction when reducing diameter, and the small end should connect to the incoming flow direction when expanding diameter. If installed in reverse, although it will not cause damage, it will affect the transition and flow direction. For eccentric reducers, in addition to the large end and small end direction, attention should also be paid to the eccentric direction. Top flat and bottom flat cannot be installed in reverse, otherwise, liquid accumulation, gas trapping, or poor drainage will occur in horizontal pipelines. For flanged reducers, it is necessary to verify the flange standards and hole position directions at both ends. Before installation, confirm the flow direction, concentric or eccentric type, and top/bottom leveling requirements according to the drawings, and mark the components before positioning. If there is doubt about the direction, verify it before welding to avoid rework after welding.

Need to provide information on airflow rate, gas mist and dust content (mist droplet size, whether it contains crystals or viscous substances), required demisting efficiency or allowable liquid carryover at the outlet, installation location and available space, cabinet material (PP or PPs), inlet and outlet orientation and flange dimensions, and whether online flushing is required. Airflow rate and demisting efficiency determine the cabinet cross-section, internals configuration, and stages, while dust and crystal content determine whether to select clog-resistant demisters or high-efficiency packings. Installation location determines the liquid drainage method and liquid seal height. Providing these parameters is essential to ensure effective demisting and reasonable system pressure drop.

Large-diameter plastic flanges have limited rigidity. If the bolt tightening force is excessive, the tightening sequence is incorrect, or the pipeline is hung improperly, the flange surface may warp or deform, leading to seal failure. Large-diameter flanges should be selected with reinforced thick flanges, appropriately increasing the number of bolts and flange thickness. During tightening, apply even force in two to three stages following a diagonal sequence; never tighten unilaterally in a single step. The weight of the pipeline and components should be independently supported by hangers; the flange should not bear the shearing force of the pipeline or the weight of the equipment. If necessary, install independent supports near both sides of the flange. After installation, check whether the flange surface is parallel and whether the gaps are uniform. During operation, if warping or air leakage is detected in large-diameter flanges, realignment, additional support, or replacement with a reinforced flange should be performed; avoid indiscriminately increasing the tightening force.

Direct-drive units do not have belts, pulleys, or other easily wearied field components, making daily maintenance simpler. Main checks involve the motor, impeller, and control system. Note that the impeller is directly connected to the motor shaft. If the impeller corrodes or the motor fails, maintenance requires disassembling the volute and impeller according to the unit structure, which is more specialized than belt replacement. It is recommended to have the manufacturer or professionals handle repairs, with spare parts matched by model. Selecting highly mold-based and serialized products while retaining model parameters ensures spare part availability. On-site space for disassembly and hoisting conditions should be reserved. Critical systems may require standby fans.

General actuators and internal components lack strong corrosion resistance; direct exposure to acidic or alkaline gases will corrode terminals, motors, and gears. Corrosion-resistant ventilation systems should use corrosion-resistant actuators (corrosion-resistant housing, sealed terminal boxes, corrosion-resistant connectors), or install standard actuators outside the clean area of the ductwork and add corrosion-resistant covers to ensure the valve shaft seal does not leak corrosive gases. Cable entry points should be sealed to prevent corrosive gases from entering, and brackets and fasteners should be made of stainless steel or treated for corrosion resistance. In highly corrosive workshops, it is recommended to prioritize specialized corrosion-resistant actuators and select based on the protection level.

Please provide the fan model, speed, airflow, pressure, and installation location. It is recommended to provide the fan noise octave band spectrum or sound power level, target noise standard (workshop or factory boundary limits), exhaust stack and duct diameter, flange standards, available installation length and space, exhaust gas composition temperature (including mist and dust), and flame retardancy requirements for materials. A spectrum and limit values are required to calculate the noise reduction amount for each frequency band and determine the lengths of the resistive and reactive sections. Providing only diameter and length can only be done based on experience, with no guarantee of noise reduction effectiveness. If complete ducting is required, specify the configuration of flexible connectors, reducers, and rain hoods.

The plastic grating board is acid and alkali resistant, rustproof, and rot-resistant, making it suitable for outdoor and corrosive environments. However, polypropylene will gradually age and become brittle when exposed to ultraviolet (UV) radiation from sunlight, leading to a decline in mechanical performance. For grating boards, platforms, and walkway panels installed outdoors for long periods, it is recommended to use weather-resistant materials with UV inhibitors or implement shading and covering measures to slow down aging. Grating boards used inside towers and equipment are not exposed to direct sunlight, so aging occurs at a slower rate, and conventional materials are sufficient for long-term use. In cold regions, the low-temperature toughness of the material must also be considered. During winter, the panels become more brittle, so heavy impact and concentrated stacking should be avoided, and handling during installation and maintenance should be gentle. Outdoor platforms can also be treated with anti-slip surfaces and regularly inspected. If panels show obvious brittleness, cracking, or powdering, they should be replaced promptly to eliminate safety hazards.

During installation, ensure the valve body's airflow direction indicator aligns with the actual airflow. Both ends of the valve should be sealed. Maintain a certain length of straight pipe sections before and after the valve to avoid proximity to elbows or diameter changes that could affect airflow stability. Leave sufficient operating space on the scale side of the valve body for maintenance. For maintenance, regularly inspect whether the valve core is flexible, check for dust accumulation or crystallization causing jamming, and verify if the spring and setting mechanism are loose. In corrosive environments, inspect the valve body and moving parts for corrosion. During laboratory renovation and cleaning stages with significant dust, provide temporary protection for the valves to prevent cement dust from entering and affecting the valve core's movement. Before operation, individually verify the air volume setting for each valve.

Follow the system sequence for troubleshooting: First, check the window opening degree and whether there are obstructions blocking airflow inside the cabinet, and whether the flow guide plates are properly installed; then, verify the correct opening of the exhaust branch duct airflow valve, check if the filters or exhaust treatment equipment are clogged, and whether the ductwork is leaking air or accumulating dust; next, inspect the fan operating status, belts and impellers, and frequency converter settings; for multi-cabinet systems, also check whether the airflow balance of each branch is compromised. For variable airflow systems, also check if the sensors, controllers, and damper actuators are functioning properly. After troubleshooting, use an anemometer to re-measure the air velocity, and readjust the airflow balance if necessary.

Need to provide the types and concentrations of main exhaust pollutants, treatment air volume, exhaust temperature, and humidity/dust conditions, required purification efficiency and emission standards, installation location (indoor or outdoor), and available space, as well as absorption liquid and wastewater treatment conditions. The pollutant types determine the absorption liquid formulation and tower materials, air volume determines the tower diameter, and concentrations and efficiency determine the number of packing layers, spray stages, and tower height. Providing these parameters allows the manufacturer to select the appropriate model and ensure compliance. Basing quotes solely on air volume and tower diameter without verifying pollutant composition can easily result in mismatched treatment capacity.

Examine the functional role of the damper. The damper is only responsible for opening during equipment operation and closing during shutdown, or only for branch switching and maintenance isolation. The valve has only two states: fully open and fully closed. Choose the on/off type for low cost, fast action, and simple control. The damper needs to adjust its opening based on signals such as face velocity, pressure difference, and concentration to control airflow volume, such as variable airflow fume hood dampers, frequency control linkage dampers, and negative pressure Adjustment dampers. These must be selected as analog control types. If unsure, determine whether the valve requires intermediate openings during operation: if not, use the on/off type; if so, use the control type. Alternatively, both types can be configured separately in the same system.

Mechanically, as long as the output shaft chuck matches the shape and size of the valve shaft, the mounting bracket can be secured, and the torque is sufficient, they can typically be compatible. However, it is recommended to purchase the valve and actuator as a set. Valve shaft diameters, square shaft dimensions, connecting flanges, and stroke limits may vary among different manufacturers. When self-providing, verify the valve shaft dimensions, rotation direction, full open/close angles, and bracket hole positions, and ensure the corrosion resistance level is consistent. Actuators supplied as a set with the valve have been matched and adjusted, ensuring greater reliability in torque, connection, and sealing, with clear post-installation responsibilities. For critical projects, it is advisable to use valves and corrosion-resistant actuators from the same manufacturer.

Please provide the fan model, airflow and pressure, rectangular duct cross-sectional dimensions, fan noise spectrum or sound power level (at least total noise value and speed), target noise reduction or factory boundary and workshop noise standards, installation location and available length, exhaust gas composition temperature and dust/fog conditions, flange standards and material requirements. Noise spectrum data is required to economically determine the silencer sheet structure and length; only providing duct dimensions can only estimate based on experience, with noise reduction difficult to guarantee. If installation space is limited, it should be stated in advance to adjust the number of sheets and layout.

Daily inspections check pressure, current, liquid level, vibration, noise, and temperature, listen for friction or abnormal sounds, and inspect pipelines and valves for leaks; regularly clean fill fragments, crystals, and sludge from water tanks and suction filters, check if nozzle sprinkling is uniform; regularly inspect impeller wear and corrosion, as wear reduces flow and pressure, and replace promptly; for vertical pumps, check motor base fixation and long shaft alignment; for horizontal pumps, check mechanical seal leaks, bearing lubrication, and coupling alignment. Long-term shutdowns should flush corrosion from pumps and pipelines and drain them, and take anti-freeze measures in winter. Establish inspection and spare part replacement records to reduce unexpected failures.

Dust, oil mist, and water mist can coat and block the pores of activated carbon, causing it to fail quickly. Therefore, a pre-treatment process including filtration, oil removal, and mist removal should be applied before the activated carbon enters the carbon box. From a safety perspective, activated carbon adsorption of organic vapors generates adsorption heat. During continuous high-concentration, high-airflow adsorption, the bed may heat up. Ketones and other substances also pose oxidation and heat release risks. The inlet concentration and temperature should be controlled, temperature monitoring and necessary fire protection measures should be installed, the equipment should be kept away from ignition sources, and the carbon bed should be purged with fresh air before shutdown. For high-concentration VOC treatment, activated carbon adsorption should not be used directly. Instead, combustion-based processes or adsorption-desorption combination processes should be selected. Specific safety designs should be implemented in accordance with regulations.

Each fume hood at the terminal is equipped with a variable air volume Venturi valve, a window displacement sensor (or face velocity sensor), and a control and display alarm panel; the exhaust system is equipped with a variable frequency exhaust fan, while the fresh air system is equipped with a variable frequency fresh air fan and a room pressure differential control. Multiple valves and fans are connected to the ventilation monitoring system via a controller and communication bus to achieve air volume summation, variable frequency linkage, status monitoring, and alarm logging. The system design must comprehensively consider the balance between exhaust volume and make-up air volume, laboratory negative pressure gradient, fan redundancy, and emergency power supply. Compared to constant air volume systems, VAV systems require higher equipment and commissioning requirements and should be designed and commissioned by professional laboratory ventilation engineers.