FAQ

In addition to providing conventional parameters such as size, wall thickness, connection method, operating mechanism, and air pressure, it is essential to clarify the flame retardancy grade of materials and applicable standards, as well as the flame retardancy matching requirements for welding rods and seals, and to request a material test report. Valves and PP flame retardant ducts should ideally be supplied by the same manufacturer to avoid inconsistencies in flange standards and material batches. For indoor installation, verify the valve length, operating orientation, and maintenance space, and confirm with the design team in advance whether additional fire dampers are required for fire-related sections to prevent rework.

For custom elbows, the following parameters are required: rectangular duct cross-sectional dimensions (length x width), elbow angle, turning direction (horizontal left/right turn or vertical up/down flip), flange type and dimensions, whether to include flow-directing vanes and the number of vanes, sheet thickness and flame retardancy requirements, as well as on-site installation space and curvature radius limitations. Providing pipeline layout drawings or on-site measured dimensions allows the manufacturer to proceed with cutting, reducing on-site modifications and ensuring first-time installation. For elbows attached to walls, beams, or avoiding equipment, note the clearances to building structures and the curvature center positions. For flanged elbows, specify whether the two ends of the flanges conform to the standards of adjacent fittings. Complete parameters and clear directions are essential to ensure the elbow curvature, flow-directing vanes, and interface dimensions match the site, avoiding rework upon arrival due to directional or dimensional discrepancies.

Hollow section steel can be modified on-site using a plastic welding gun and spare plates for minor adjustments, such as opening branch holes, adding short tubes, or adjusting local layouts. However, the overall cross-sectional dimensions and reinforcement structures are more reliably determined in the factory according to the drawings. After on-site modifications, new welds must be continuously sealed, and flanges or reinforcement frames must be added at new openings. Weakened wall plates require additional welding of reinforcement bars to maintain original strength. For significant dimensional changes, it is recommended to return to the factory or have professional machining personnel re-manufacture according to the drawings to avoid on-site modifications affecting strength, sealing, and flame retardancy compatibility. Welding electrodes used for on-site repairs must match the base material in terms of material and flame retardancy grade; ordinary electrodes cannot be used. After modifications, visual and air leakage inspections must be conducted to confirm the qualification of welds, reinforcements, and flanges before putting into use. On-site modified areas must be marked in the completion documents.

Provide rectangular valve body cross-sectional dimensions (width x height), square flange dimensions and hole positions, number of valve leaves or valve height, valve shaft direction, actuation method (manual, on/off electric, or analog electric with signal type), actuator torque and protection requirements, material flammability rating, seal strip requirements, air duct pressure and medium composition. For VAV systems, provide control method and valve position feedback requirements. Attach fume hood exhaust drawings and ceiling access panel location to ensure correct valve operation orientation.

Electrical considerations require reserving power supply, control cables, and junction boxes near the valve that match the actuator voltage; for analog models, signal cables and shielded grounding must also be installed. Spatial considerations should allocate space for actuator installation/removal, manual operation, and maintenance, while avoiding water dripping above the actuator. Mechanical considerations demand that the actuator bracket be secure, the valve shaft and actuator be coaxial, and the valve body weight be supported by pipe brackets rather than the actuator. For outdoor or humid locations, select high-protection-rated models with rainproof features. Before commissioning, verify that the power supply voltage matches the actuator's nameplate.

For custom size reducers, provide the diameters of both ends (diameter for round pipes, length and width for square pipes), the reduction type (concentric or eccentric, and flat-side direction), the length of the reducing section or allowable taper angle, connection methods and flange standards at both ends, airflow direction (convergent or divergent), plate thickness, and flame retardant requirements. When matched with fans, provide the fan interface dimensions and Take over direction to ensure the reducer type aligns with the fan. Providing pipeline drawings or on-site measured dimensions guarantees a successful first-time connection, avoiding errors in flange hole positions and orientation. For eccentric pieces, specify whether the top or bottom of the pipe is flat. For flanged pieces, indicate whether the flange standards at both ends are consistent. With complete parameters, the manufacturer can cut based on the taper angle, which not only controls resistance but also ensures on-site installation, reducing temporary pipe modifications and rework.

How many meters of weld bead can be welded with one kilogram of welding electrode depends on the electrode diameter, groove dimensions, gap size, and number of welding layers, with no uniform value. Fine round electrodes used for single-pass welding on thin plates allow for longer welding lengths per kilogram; triangular electrodes or double-wire electrodes used for filling thick plate grooves have high single-pass deposition rates, significantly reducing the welding length per unit weight. The accurate quantity should be calculated and summarized layer by layer based on plate thickness, groove angle, total weld length, and number of welding layers. When preparing materials for a project, a certain surplus should be added to the theoretical quantity to account for cutting losses, rework, and on-site welding, avoiding material shortages that could delay construction. The specific welding length can be obtained from the manufacturer based on the selected electrode specifications, and then adjusted by actual consumption during the first piece trial welding for more accurate material preparation.

The actuator power voltage must match the nameplate specifications. Common voltages include AC 220V and AC or DC 24V. Wiring should be performed by an electrician according to electrical drawings, ensuring proper grounding and protection. Control and feedback lines should be connected to the control cabinet and routed separately from power lines. Analog signal lines should use shielded cables with single-ended grounding. Leave sufficient cable slack for maintenance and ensure proper sealing at cable entry points. For humid and corrosive environments, select actuators with appropriate protection ratings and apply anti-corrosion treatments or install protective covers. Cable entry points should prevent corrosive gases and moisture from entering the junction box. Commissioning should follow the sequence of manual operation first, then electric operation. Limit switches are pre-adjusted at the factory and should not be altered arbitrarily. Valves that remain non-operational for extended periods should be powered on periodically to check the motor, limit switches, and valve shaft, preventing jamming due to prolonged inactivity.

The concentric sleeve has symmetrical structures at both ends and no installation direction requirement. However, it must ensure that both sections of the ducts are inserted to the same depth and aligned centrally in the sleeve. Avoid inserting one end fully while leaving the other end hanging, as this will cause uneven weld stress and potential air leakage. Before splicing, clean the pipe ends of burrs, debris, and oxidation layers. Align the duct axis and level it before welding circumferentially. For special sleeves with flow direction requirements or joints with internal flow guides, install them according to the shell's marked airflow direction and never in reverse, as this will increase resistance and affect flow guidance. When adjacent to eccentric components or flow guide fittings, verify the overall direction as well. Before installation, confirm the fitting type and flow direction against the drawings. After welding, recheck the alignment gap and centering.

The quick welding tip features a welding electrode guide channel, where the electrode is preheated by hot air as it passes through the tip. The welder can control both the gun and the electrode with one hand, enabling fast travel speeds and uniform, consistent weld bead formation. It is ideal for long straight welds and batch construction, significantly improving efficiency and reducing reliance on technique. The standard round tip requires a second hand to feed the electrode, with adjustable angles and speeds for high flexibility, making it suitable for complex areas like elbows, pipe bends, and flange corner seams, as well as tight spaces. When used with proper temperature and technique, both tips offer comparable welding strength; the main difference lies in construction efficiency and application areas. In engineering practice, the quick tip is typically used for long straight sections, while the round tip handles edges, corners, and irregular areas. The two are often used in combination. When equipped with a gun, each type of tip comes with a set, and the corresponding specifications should be selected based on the electrode diameter.

Cannot be directly compatible; the body shape of round and square valves must match the cross-section of the air duct. Forcing connection will result in cross-sectional misalignment and air leakage. Square air ducts should be paired with square manual dampers, connected via square flanges to square pipes. Round air ducts should be paired with round dampers, connected via spigot or flange. If a system requires transitioning between round and square pipe sections, use square-to-round adapter for smooth transition before connecting to the corresponding cross-section damper. Avoid using reducers or rigid/soft connections, as this will cause gap leakage, flow deviation, and local resistance. When ordering, select dampers based on the air duct cross-section shape and verify flange or spigot dimensions. In projects with frequent use of both square and round cross-sections, it is recommended to arrange the transition nodes uniformly to reduce the number of special-shaped fittings, which also facilitates future spare parts and maintenance.

First, accurately locate and mark holes on the cylinder based on the dimensions of the window flange base, ensuring the holes are positioned away from weld seams and reinforcement ribs. The hole edges should be polished smooth and burrs removed. After placing the flange base into the holes, adjust its position to ensure the window is centered, bolt holes are aligned for easy operation, and then weld continuously around the outer periphery of the base, ensuring the weld seams are tight and free of voids. During welding, protect the sealing surface and transparent window panel. It is recommended not to install the panel or sealing strips initially. After welding, allow the cylinder to cool and remove slag before assembling the transparent components to avoid heat damage from welding high temperatures to the panel and rubber strips. During assembly, ensure the sealing strips are continuous and smooth, and tighten the cover diagonally evenly. After installation, perform a leak test to confirm the window is centered, the panel is intact, and there is no leakage before putting it into use.

Not applicable. Check valves automatically prevent reverse flow and remain open during forward flow, cannot actively shut off forward airflow, nor remote control; electric sealed valves can actively close per command for bidirectional isolation but require power and control signals, with status depending on reset mode during shutdown/power loss. Check valves are simple and reliable for preventing backflow at fan outlets, while electric or manual sealed valves are used for maintenance isolation and hazardous gas cutting; both are used in series for high-demand applications, each performing automatic check and active isolation functions.

Seal material must be selected based on exhaust composition, concentration, and temperature; common corrosion-resistant elastomers each have specific applications, some resistant to acids but not solvents, others with varying temperature tolerances. When ordering, provide the manufacturer with complete medium conditions, including acid/base types, organic solvents, oil mist, concentration, and temperature, for them to select and verify compatibility if necessary. Spare parts replacement on-site must use the same material; do not substitute with ordinary rubber rings, as corrosion and swelling will otherwise compromise sealing integrity.

For minor blockages, online flushing can be performed by increasing the rinsing flow rate and extending the rinsing duration using the spray system. Alternatively, after shutdown, high-pressure water can be used from the manway to flush the packing layer from top to bottom, dislodging crystals, dust, and sludge, which are then discharged into the sump with wastewater. Soluble salt crystals can be cleaned by circulating dilute acid or dilute alkali corresponding to the medium for immersion cleaning to enhance dissolution. However, the suitability of the cleaning fluid concentration and temperature for the tower, packing, and sealing components must be verified first. After cleaning, the tower should be thoroughly rinsed with clean water. If the blockage is severe, resistance remains high even after flushing, or the packing is aged, broken, or hardened, the packing should be removed for a comprehensive cleaning of the tower, grating, and nozzles. New packing should then be installed to restore the purification capacity. During packing removal, inspect the tower wall, support rings, and spray pipes. Reinstall the packing, spread it evenly, and secure the pressure plates. Maintain regular rinsing and resistance records for routine management.

Both are used for anti-corrosion walkways, but the materials and applicable scenarios differ. PP stair treads are injection molded, acid/alkali resistant, with anti-slip protrusions on the surface, lightweight, and easy to replace individually, making them suitable for electroplating tank edges and personnel walkways on production line sides. GRP grating has high strength, high load-bearing capacity, and is permeable to light and water, making it suitable for large-scale operating platforms and vehicle-accessible areas. However, the cut edges expose fibers, so the corrosion resistance of the resin and aging should be monitored in long-term strong corrosive environments. For pedestrian walkway edges, PP stair treads are economical and lightweight with anti-slip and leak-proof features. Heavy-duty platforms and vehicle-accessible areas can consider GRP grating. When selecting, compare comprehensively based on load, medium, permeability to light and water, and cost-effectiveness. They can also be used in different zones within the same workshop: plastic stair treads for tank edges and GRP grating for concentrated load-bearing platforms, each leveraging their strengths.

Custom machining of dampers requires providing the valve body diameter, wall thickness, and material (standard PP or flame-retardant PP), vane type and quantity, connection methods and flange standards at both ends, installation length, actuator type (handle or worm gear and installation orientation), whether a soft seal closure is required, pipeline air pressure and medium composition, and whether an electric actuator interface is reserved. For large-diameter valves, installation drawings and on-site operating space dimensions should be provided, allowing the manufacturer to design reinforced structures, shaft seats, and mechanism positions accordingly. For electric or automatic control requirements, the power supply, control signals, and adjustment specifications must be specified. If installed indoors or in suspended ceilings with fire safety requirements, the use of flame-retardant materials should be noted. Complete parameters and drawings are essential to ensure the valve's strength, operating method, and interface dimensions match the site, reducing modifications upon arrival.

For custom-made square butterfly valves, the following information is required: the inner cross-sectional dimensions (width x height) of the rectangular valve body, flange outer frame dimensions and hole positions, vane type and quantity requirements, valve body thickness, valve shaft orientation (horizontal or vertical), handle or actuator installation orientation, material (standard PP or flame-retardant PP), whether to add a sealing strip, and pipeline air pressure and medium composition. Providing an air duct cross-sectional drawing and installation space photos helps the manufacturer determine the operating orientation and reinforcement method. Incorrect valve shaft orientation and operating orientation can result in on-site inoperability or maintenance difficulties, so it must be clearly marked on the drawings. For electric control requirements, specify the control signal, power supply, and actuator torque requirements. Complete parameters and clear drawings are essential to ensure the valve matches the air duct, actuator, and on-site space upon arrival, avoiding rework.

For custom electric square butterfly valves, provide the following information: rectangular valve body cross-sectional dimensions (width x height), square flange dimensions and hole positions, number of vane plates, actuator type (on/off or regulating), power voltage, control and feedback signal format, protection rating, whether a power failure reset is required and the reset direction, material (standard PP or PP flame retardant), seal strip requirements, duct air pressure, and medium temperature. Also provide equipment interlock control requirements and electrical interface diagrams to facilitate actuator wiring and system matching. For installations within suspended ceilings, specify the maintenance port location and actuator orientation. For outdoor or damp locations, indicate protection and rainproofing requirements. Complete parameters and clear control logic are necessary for the manufacturer to configure actuator torque, limit switches, and feedback components, ensuring both electrical and mechanical alignment upon valve delivery.

To confirm the complete composition and concentration of the exhaust gas (including dust content, oil content, water content, and temperature), treatment air volume and fluctuation range, emission compliance standards, available absorbents, and wastewater treatment destination, installation site, and fire safety requirements. The composition determines the absorbent and whether mixed towers are feasible, concentration and standards determine the tower diameter, packing stages, and liquid-to-gas ratio, temperature determines material selection and whether pre-cooling is required, and dust and oil content determine whether pre-treatment is necessary. Installing equipment without clear conditions may lead to issues such as incorrect absorbent selection, undersized tower diameter, packing blockage, and non-compliant treatment. In such cases, exhaust gas testing should be conducted before design.