FAQ

The stainless steel spray tower is a vertical wet exhaust gas purification equipment that achieves washing through countercurrent contact between gas and liquid. The exhaust gas enters the tower from the tangential inlet at the bottom, rises through the packing layer, and comes into countercurrent contact with the liquid sprayed by nozzles. Gaseous acid and alkali pollutants are captured by the liquid phase and neutralized, while dust and soluble substances are simultaneously carried away by liquid droplets. After washing, the gas is dehydrated by a mesh demister and discharged through the top exhaust stack via a fan. The absorption liquid falls into the bottom water tank of the tower and is then transported to the top of the tower by a circulation pump for repeated spraying and closed-loop circulation. The entire process ensures thorough gas-liquid contact, enabling continuous treatment of acid and alkali exhaust gas and acid mist, with stable operation and low maintenance requirements.

V0 rating indicates that the enclosure material self-extinguishes quickly upon contact with a flame in standard combustion tests, demonstrating strong flame retardancy. This significantly reduces the risk of the enclosure being ignited by external heat sources and the spread of flames along the equipment. However, it does not guarantee that the equipment will never catch fire. Activated carbon adsorbs organic substances, releasing adsorption heat. When adsorbing high concentrations of VOCs or when the bed fails to dissipate heat properly, the carbon layer may heat up. Both activated carbon and organic substances are combustible. Therefore, even with V0-rated enclosures, it is still essential to control inlet concentration and temperature, implement temperature monitoring and alarms, and adopt fire protection and shutdown purging measures. Do not mistake material flame retardancy for process safety. The fire protection design of the entire adsorption system must comply with regulations.

Both are acid and alkali resistant, differing in flammability rating. Standard PPs sheets have limited flammability with a low rating, while V0 PPs sheets self-extinguish quickly upon fire exposure and do not produce flaming drips in standard combustion tests, offering stronger flammability resistance. They are suitable for high fire protection requirements in indoor spaces, equipment layers, basements, etc. Standard PPs sheets can be used for outdoor or low fire protection requirement applications to control costs. When selecting, ensure the entire indoor system (ducts, fittings, dampers, flexible connectors) is made of V0 material and provides flammability test reports. V0 should not be used only locally, otherwise the system's flammability continuity will be compromised.

In scenarios with moderate acid gas concentration, low gas volume, water scarcity, or where cold conditions make water washing inconvenient, SDG dry adsorption can be used alone and achieves excellent results without wastewater or anti-freeze issues. However, for high concentration, high-temperature, high-humidity, or exhaust gases containing heavy mist droplets and dust, spray washing offers greater advantages in processing capacity, cooling, and adaptability. In such cases, it is recommended to first treat most of the acid gas with a spray tower, then use an SDG dry adsorption unit for final deep filtration. These two methods are not simple substitutes; they should be selected based on acid gas concentration, gas volume, temperature and humidity, on-site water supply and drainage conditions, and economic factors, and can also be used in series for complementary effects.

When the fan is operating, the motor and impeller generate vibration. If the fan is directly connected to a rigid duct, the vibration will be transmitted along the duct, causing duct resonance, bracket loosening, flange leakage, and noise amplification. In the long term, it may lead to fatigue cracking of welds and joints. A flexible vibration isolation break is formed between the fan and the duct by the soft joint, absorbing vibration displacement and compensating for thermal expansion and contraction of the duct and installation deviations. This is a common practice to reduce noise and protect the pipeline network. One soft joint is installed at both the fan inlet and outlet for more reliable vibration isolation. The soft joint should be installed as close to the fan body as possible, with independent brackets for both ends of the duct and equipment, keeping the soft joint in a free, non-load-bearing state. In addition to vibration isolation, the soft joint also facilitates fan disassembly and reassembly and correction of minor misalignments. If soft joints are not installed at the fan inlet and outlet, vibration and noise issues will significantly increase, and later modifications will also be more troublesome.

For ambient temperature, moderate corrosivity, budget-sensitive applications, and PVC duct systems, choose PVC dampers. They are economical, lightweight, have good rigidity, and feature easy splicing adhesive installation, suitable for general corrosion-resistant exhaust and building ventilation. For strong acids/alkalis, flammability requirements, higher gas temperatures, or PP welded duct systems, select PP or PPs dampers. They offer better temperature and corrosion resistance, and can be thermally welded and paired with flame-retardant materials. Both share the same structural principle, with the main differences being material temperature resistance, flame-retardant performance, and connection methods. Selection should be based on exhaust composition, temperature, fire safety requirements, and pipeline material. It's recommended to standardize valve material and connection methods within the same system for easier construction and spare parts management. When unsure about medium composition, choose materials for stronger corrosivity and higher temperatures to prevent premature aging and deformation of valves in critical areas.

Primarily determined by installation space and connection conditions. The equipment can only be placed indoors, in basements, or mezzanines when the ceiling height is insufficient for installing vertical towers, or when overhead craning is not feasible on-site. In such cases, a horizontal tower is selected, trading height for planar length. When the main exhaust duct is horizontally laid, it is desirable for the equipment's inlet and outlet to connect directly with the ductwork, reducing the need for vertical pipes and elbows, making horizontal tower connections more convenient. If outdoor space and height are not restricted, vertical towers offer higher counter-current mass transfer efficiency and occupy less area, typically being more economical. Both types operate on the same purification principle, with the choice primarily based on on-site layout conditions.

Both materials are made of polypropylene as the base material. The difference lies in that the PP sheet is added with flame retardant components during the production process, enabling the material to self-extinguish when exposed to fire. Ordinary PP sheet will continue to burn and produce dripping when it comes into contact with an open flame, whereas the PP sheet can prevent the spread of fire when exposed to flames and will extinguish itself once the heat source is removed. In applications requiring fire resistance, such as exhaust gas treatment and indoor ventilation, PP flame-retardant sheet should be selected. The acid and alkali resistance of both materials is essentially the same, and the welding processing methods are also identical.

Two-color PP flame-retardant sheet materials share the same basic raw materials and production processes. Prices primarily fluctuate with thickness, purchase volume, and market raw material conditions, with color itself typically not constituting a significant price difference. Beige is the industry's traditional color, with substantial market inventory, resulting in shorter delivery cycles for standard thicknesses. Porcelain white sheets are mostly produced based on orders, and small-batch purchases may involve slight variations in price and lead time. When inquiring, provide thickness, dimensions, and quantity to receive corresponding quotes. For large-volume purchases, custom-cutting can be negotiated to reduce edge waste and improve material utilization. If both colors meet the appearance requirements, prioritize the readily available beige for more reliable supply and replenishment.

Switch-type only has two positions, full open and full close, receives switch signal for air duct on/off and interlock; analog-type can receive continuous signal and stop at any position, and feedback continuous valve position signal for automatic air volume regulation. Variable air volume ventilators, negative pressure control, and frequency conversion linkage must use analog valves; simple equipment follow-up on/off can use switch valves. Analog valves are more expensive and have more complex control, choose based on whether continuous regulation is needed, do not use switch valves for frequent point-to-point simulation regulation.

Check valves installed on the outlet of indoor anti-corrosion fans, long-mounted in ceilings, pipe shafts, or workshops and connected to PPs flame-retardant ducts, become fire weak points in the entire flame-retardant pipeline system if made of ordinary combustible PP, potentially igniting first and spreading along the pipes during a fire. By adopting PPs flame-retardant check valves, the valve matches the flame-retardant grade of the duct and damper materials, self-extinguishing away from the fire, while retaining automatic anti-backflow functionality, meeting both fire protection and anti-corrosion requirements for indoor anti-corrosion exhaust engineering.

Capacity is determined based on daily chemical consumption, replenishment cycle, and preparation batches. Generally, the effective capacity is designed according to the chemical usage for several consecutive days of system operation, considering additional space for mixing and liquid level protection to avoid frequent daily preparation and prevent excessive chemical sedimentation or degradation due to large capacity. Complete dosing systems are often configured with one in use and one on standby or alternating double drums. Provide the treatment air volume, pollutant concentration, type of absorption chemical, and desired replenishment cycle, and the manufacturer or designer can calculate the capacity and number of drums accordingly.

The straight tee connects the branch pipe and the main pipe at a right angle, featuring simple processing and minimal space occupation. However, the direct intersection of airflow at right angles results in significant local resistance, making it suitable for areas with low branch pipe airflow, low wind speed, or limited space. The inclined tee joins the branch pipe to the main pipe at an acute angle along the airflow direction, ensuring smooth airflow convergence, low resistance, and low noise. It is preferred for high-flow branch pipes and systems with strict energy-saving and noise reduction requirements. When conditions permit, the branching and merging of exhaust main pipes should ideally use inclined tees to allow airflow to merge smoothly along the main pipe direction. In cases of budget constraints or limited space, small-flow branch pipes can use straight tees, but airflow dampers should be installed to balance resistance. Selection should consider the airflow ratio between the branch pipe and the main pipe, the included angle, and installation space, with particular attention to the impact of tee type on total resistance in high-flow, long-distance transportation systems.

Formed ducts are extruded or injection-molded with standard diameters and uniform wall thickness, offering low cost and fast delivery, suitable for branch ducts and conventional sections within the standard series; fabricated ducts are roll-welded from sheet metal with flexible diameters and wall thickness, capable of large diameters, thick walls, and special lengths, suitable for high-airflow main ducts, non-standard equipment interfaces, and specifications not covered by formed ducts; in projects, formed ducts are typically used for branch ducts and conventional sections, while fabricated ducts are used for main ducts and non-standard sections to balance cost and adaptability.

No. The function of PPs fire-rated dampers is to regulate airflow and isolate ventilation pipes, while fire self-extinguishing only indicates that the material itself is not easily combustible. It does not have fire protection functions such as temperature-sensitive melting, automatic closing, and fire integrity. According to fire protection codes, fire-certified fire dampers or smoke exhaust dampers must be installed where ducts penetrate fire compartments, machine rooms, and floor slabs. Fire-rated dampers only address the fire resistance of plastic pipes themselves and cannot be mutually replaced. Fire dampers must be installed at penetration points in accordance with building fire protection codes, and must pass construction drawing review and fire inspection.

When airflow changes direction at a bend, the velocity distribution is uneven between the outer and inner sides. The inner side is prone to forming eddies and flow separation, resulting in significant local resistance and noise, which is more pronounced at high airflow and high velocity. Flow guide vanes divide the air duct into several smoothly curved branch ducts, guiding the airflow to turn uniformly, which can significantly reduce the bend resistance coefficient. They also reduce wear and vibration on the outer side of the bend, showing notable effectiveness in large-section, high-velocity rectangular ducts. For small-section, low-velocity bends, the inherent resistance is limited, and flow guide vanes can be omitted to reduce costs and machining difficulty. Whether to install flow guide vanes and the number of vanes should be determined through resistance calculations based on velocity, cross-sectional dimensions, and deflection angle. For bends with flow guide vanes, the airflow direction must be noted—the flow curve should align with the direction of turn; installation in the opposite direction will be counterproductive. The ends of the flow guide vanes must be securely welded to the wall panels to prevent loosening during operation, which could generate noise.

The main advantages of square tubes are space-saving and flexible layout. When the workshop ceiling height is limited, pipes need to be attached to beams or ceilings, laid within suspended ceilings or equipment mezzanines, or need to connect with square air dampers or rectangular outlets of ventilation cabinets, choosing square tubes is more suitable, effectively utilizing flat and wide spaces and reducing bending. Round pipes have uniform stress distribution, low air resistance, less material consumption, and strong pressure-bearing capacity. They are preferred for outdoor main pipes and high-negative-pressure pipe sections. In practical projects, square tubes are often used in indoor compact sections, round pipes in outdoor main sections, and square-to-round transition fittings are used for smooth transitions at roof outlets or fan connections. Selection should be determined comprehensively based on building space, cross-sectional stress, and equipment interfaces. Rectangular tubes are commonly used in suspended ceilings, while circular tubes are preferred for long-distance transportation and high-negative-pressure sections. The combination of both maximizes space utilization and operational energy efficiency.

The exhaust from fume hoods contains acidic and alkaline gases generated during experiments, as well as potential volatile organic compounds (VOCs), which are corrosive. Plastic corrosion-resistant dampers are required. Additionally, fume hood exhaust ducts are often routed within ceilings and pipe shafts, spanning across rooms, floors, and fire compartments. Fire safety regulations mandate that duct materials be flame-retardant to prevent the spread of fire along concealed ducts and shafts. PPs flame-retardant square dampers meet both corrosion-resistant and flame-retardant requirements. Their rectangular cross-section matches the fume hood outlet and the flat-wide ducts within the ceiling, making them a common choice for laboratory exhaust systems. The damper should be paired with flame-retardant rectangular ducts and fire dampers to form a complete corrosion and fire protection system. When selecting, verify the flame-retardant grade of the material and the dimensions of the rectangular interface. Fire dampers must be installed at fire compartment boundaries, and plastic dampers cannot be used as substitutes.

Switched electric dampers are suitable for simple on/off control, remote actuation, interlocking, and maintenance isolation with low cost, while analog Adjustment electric dampers are ideal for continuous valve position adjustment based on sensor signals to precisely control airflow or maintain constant face velocity/negative pressure, with actuators receiving standard analog signals to stop at any angle; switched types are used for multiple branch circuits requiring only on/off control, while analog types are used for VAV fume hoods and VFD linkage systems.

Okay. The base material of the flame-retardant welding rod remains polypropylene, which is the same material as standard PP sheets. Upon hot melt, it can fuse reliably, and there are no issues with weld strength or seal integrity. When flame-retardant welding rods are used to weld standard PP sheets, the weld area will retain certain flame-retardant properties, but the other parts of the base material remain non-flame-retardant. Therefore, the overall flame-retardant rating of the component is still determined by the base material and cannot be altered by the welding rod. Conversely, standard welding rods are not recommended for welding flame-retardant PP sheets, as the non-flame-retardant weld joints would become the weakest points in the entire pipeline, burning first in the event of a fire. When welding flame-retardant sheets, flame-retardant welding rods should be used consistently to ensure the flame-retardant performance of the weld matches that of the base material. In engineering applications, welding rods should be procured in sets according to the base material type and color to avoid mixing.