Features

High installation location: Elevated ducts are generally installed at the top of buildings, above ceilings, or on steel structures at high elevations to provide ventilation or air conditioning coverage for specific areas.

Efficient use of space: It can deliver air to the required areas without occupying floor space. This is particularly important for places with limited space, such as industrial plants, large warehouses, and gymnasiums, as it can effectively utilize vertical space and improve space utilization.

Long air delivery distance: Due to the high installation position, the air duct can utilize natural air flow and pressure differences to deliver air over long distances, thereby achieving large-area ventilation or air conditioning coverage.

Aesthetically pleasing: Elevated ductwork is typically installed at a height where it is not easily visible to people, thereby minimizing its impact on the appearance of the building and keeping the interior neat and attractive.

High construction difficulty: Installation at high altitudes requires specialized high-altitude work equipment and technical personnel. Safety issues must be addressed during construction, which also increases the difficulty and cost of construction.

Maintenance inconvenience: Due to its elevated position, maintenance personnel need to use professional climbing equipment to perform repairs, maintenance, and other tasks, which increases the difficulty and cost of maintenance and places higher demands on the skills and safety awareness of maintenance personnel.

application scenarios

Industrial plants: Used to remove exhaust gases, dust, and heat generated during production, provide fresh air, improve the working environment, protect workers’ health and safety, and also help protect equipment and improve production efficiency.

Large warehouses: such as automated multi-level warehouses, which can control the temperature and humidity of different areas within the warehouse to ensure proper storage conditions for goods and prevent them from becoming damp, moldy, or spoiled.

Commercial buildings: such as shopping malls, supermarkets, shopping centers, etc., used to regulate indoor air temperature, humidity, and air quality, providing customers and employees with a comfortable shopping and working environment.

Sports venues: Able to meet the ventilation and air conditioning needs of large numbers of spectators and athletes in sports venues, ensuring fresh air and comfortable temperatures inside the venue, thereby enhancing the spectator experience and the competitive performance of athletes.

Transportation hubs: such as train stations and airports, can effectively regulate the air environment in areas such as lobbies, waiting rooms, and waiting areas, providing passengers with a comfortable waiting space.

Installation points

Construction plan formulation: Based on the specific conditions of the construction site, including building structure, duct installation location, height, quantity, specifications, and models, formulate a detailed construction plan, clarify construction objectives and construction sequence.

Safety measures: Set up safety warning signs at the construction site, cordon off the construction area, and prevent non-construction personnel from entering. Set up a suitable aerial work platform, ensure that the platform legs are evenly distributed, install guardrails and anti-slip boards, and set up safety nets below the work platform.

Duct inspection and hoisting: Inspect the ducts before construction to ensure that they are free of damage, deformation, and other issues. Set hoisting points based on the length and weight of the ducts, generally at both ends and in the middle, and use special lifting lugs to secure them firmly. During hoisting, a designated person should be in charge to ensure that the ducts are lifted vertically and do not hit nearby obstacles.

Duct connection and sealing: Align the duct ends and ensure that the interface is flat and straight. Use sealing tape, sealant, or flanges to seal the duct system and prevent air leakage. For duct bends and diameter changes, use special elbow components and diameter change pipes, and pay attention to the sealing of the interface.

Installation Quality Inspection: After installation is complete, inspect the installation quality of the ductwork section by section, including whether the ductwork is straight, whether the connections are secure, and whether there are any air leaks. Use professional testing instruments to conduct airtightness tests, airflow and air velocity tests, etc., on the ductwork system to ensure that it meets design requirements.

1. Classification of air ducts by material and specification characteristics

Different types of ductwork vary in terms of material, specifications, and applicable scenarios:

Galvanized steel sheet ductwork
Thickness: Determined based on duct dimensions, commonly ranging from 0.5mm to 2.0mm (e.g., for rectangular ducts with a long side ≤320mm, thickness is 0.5mm; for long sides between 1600mm and 2000mm, thickness is 1.2mm).

Size range:
Rectangular ducts: Long sides typically range from 120mm to 2000mm, with corresponding short sides from 60mm to 1250mm (e.g., 320×200mm, 800×400mm, etc.). Larger
sizes require customization.

Round ducts: Diameter generally ranges from 100mm to 1600mm (e.g., φ150mm, φ800mm, etc.), with extra-large diameters requiring welding.

Fiberglass ductwork

Dimensions: Rectangular ducts can be up to 3000 mm long, circular ducts can be up to 2000 mm in diameter, with wall thicknesses ranging from 5 mm to 10 mm. These ducts are corrosion resistant but relatively heavy, making them suitable for use in humid environments.

Stainless steel ductwork

Dimensions: Similar to galvanized steel ductwork, but thicker (generally 0.8 mm to 3.0 mm), suitable for clean rooms, food processing plants, and other locations requiring corrosion resistance.

2. Duct Dimension Notation Rules

Rectangular ducts: denoted as “long side × short side” (unit: mm), e.g., “500×320mm” indicates a long side of 500mm and a short side of 320mm.

Round ducts: Denoted as “diameter φ + numerical value,” e.g., “φ300 mm” indicates a diameter of 300 mm.

Dimension tolerances: National standards permit ±1 mm to ±3 mm (depending on size) to ensure connection sealing integrity.

3.Selection Criteria for Duct Specifications

Air flow Requirements: The cross-sectional area of the duct is related to the air velocity. The calculation formula is: Airflow (Q) = Cross-sectional Area (A) × Air Velocity (v) × 3600 (Unit: m³/h)

Air velocity must be reasonable (e.g., main duct air velocity in HVAC systems: 8–12 m/s; branch ducts: 3–6 m/s). Excessively high air velocity can cause excessive noise and resistance, while excessively low air velocity may result in overly large duct dimensions.

System Pressure: High-pressure systems (>1500 Pa) require thicker panels and reinforcement measures; duct dimensions should not be too large. Low-pressure systems (≤500 Pa) can use thinner panels.

Installation Space: Constrained by building ceiling height, beams, etc., duct dimensions must be balanced with spatial layout (e.g., rectangular ducts are preferred in narrow spaces to save height).

4.Notes

Duct specifications must comply with the “Code for Acceptance of Construction Quality of Ventilation and Air Conditioning Engineering” (GB 50243) to ensure strength and airtightness.

Non-standard ducts (e.g., elliptical) must be custom-made, with specifications calculated based on equivalent cross-sectional area.

Large-sized ducts (long side > 2000 mm) must be equipped with reinforcing ribs to prevent deformation.

Selecting appropriate duct specifications can ensure system performance while reducing costs and installation complexity.

PP square ducts have a modular design, a design concept that greatly simplifies the installation process. Each module is like an independent component, and at the construction site, the installer can quickly put the modules together like building blocks. This approach not only reduces the time and workload of on-site processing, but also reduces the probability of errors in the installation process.

PP square ducts offer a variety of choices in terms of connection methods. Heat fusion connection is one of the commonly used methods, through the special heat fusion machine to heat the air duct port, so that it melts and quickly butt and apply pressure, after cooling, the joint can be tightly combined to form a solid whole. The advantage of this connection method is that the strength of the connection is high, almost equal to the strength of the pipe body, and can effectively prevent leakage. In some places that require very high sealing, such as laboratories, pharmaceutical workshops, etc., PP square ducts with heat fusion connection can meet the needs very well.

Flange connection is also one of the common connection methods. First, the flange is welded to the duct port to ensure that the flange is horizontal and there is no gap, and then a bolt is placed in the middle of the flange to tighten the two flanges and align the ports, and finally a sealing gasket is used to seal the gap to ensure that there is no air leakage in the connection. This type of connection is relatively simple to operate, easy to disassemble and repair, and is suitable for some ventilation systems that require frequent maintenance and adjustment.

In the installation process, the sealing treatment is crucial. Regardless of the type of connection, it is important to ensure that the sealing material is used correctly. Commonly used sealing materials include rubber gaskets and sealants. When selecting the sealing material, it should be determined according to the environment in which the duct is used and the medium to be conveyed. When conveying corrosive gases, chemical-resistant sealing materials should be selected to ensure the durability of the sealing effect.

In addition, the installer needs to pay attention to the installation position and direction of the duct to ensure that it meets the design requirements. Plastic shims with a thickness of 3-5mm should be inserted between the duct and the bracket to minimize friction and vibration. The distance between the brackets is generally 1.5 – 3m, for the side length or diameter greater than 1250mm duct, lifting shall not exceed 2 sections; side length or diameter less than 1250mm duct, combined lifting shall not exceed 3 sections. When handling the duct, it should be carried gently and put down gently to avoid falling and touching to prevent cracks. When lifting vertically, control ropes should be tied to prevent the air duct from swinging and collision and rupture.

(ii) Maintenance

The routine maintenance of PP square duct is relatively simple, mainly including cleaning and inspection. Because of its smooth surface, dust and dirt are not easy to adhere to, so cleaning is very convenient. Regularly wipe the surface of the duct with a damp cloth to keep it clean. For the inside of the duct, you can use professional cleaning tools, such as duct cleaning brushes, vacuum cleaners, etc., to remove accumulated dust and debris to ensure smooth ventilation. In some dusty industrial places, quarterly internal cleaning can meet the requirements.

The inspection work is mainly to see whether the connection parts of the air duct are loose, whether there is any leakage phenomenon, and whether there is any damage to the air duct body. Regular inspections can detect potential problems in time and avoid malfunctions. It is generally recommended to conduct a comprehensive inspection every six months. When checking the connection parts, pay attention to see whether the bolts are tight, and whether the sealing gasket is aging or damaged. If problems are found, they should be repaired or replaced in time. For damage to the duct body, small cracks can be repaired with special repair materials, while larger damage requires replacement of the damaged section.

The stability of PP material makes PP square ducts have low maintenance cost. Compared to metal ducts, it does not require corrosion protection and there is no need to worry about rust. Under normal use, PP square ducts are only 30% – 50% less expensive to maintain than metal ducts. And, because of its long service life and low replacement frequency, long-term maintenance costs are further reduced. In commercial buildings, the use of PP square duct ventilation systems can save tens of thousands of dollars in annual maintenance costs.

The maintenance cycle varies according to different use environments and places. In commercial and public places, such as shopping malls, office buildings, etc., it is recommended to carry out a comprehensive maintenance once a year; in industrial places, due to the harsher environment, the maintenance can be carried out once every half a year; the ventilation system of the residential houses is used less frequently and the environment is relatively good, so it is enough to carry out a maintenance once every 2 – 3 years. Of course, if the ventilation system appears obvious odor, air volume decreases or energy consumption increases and other abnormalities, it should be promptly inspected and maintained.

In the chemical and electroplating industries, the production process often produces various gases with strong corrosive properties, such as sulfuric acid, hydrochloric acid, sodium hydroxide, etc. PP ducts can easily cope with these “acid and alkali attacks” by virtue of their excellent chemical resistance. In the sulfuric acid plant, PP ducts are used to transport high concentration of sulfuric acid vapor, and after a long time of use, the inner wall of the ducts is still smooth as before, without the slightest trace of corrosion. While the traditional metal duct, in the same environment, may be just a few months will appear serious corrosion, resulting in pipe leakage, not only affect the production, but also may bring potential safety hazards. According to relevant data, in the chemical industry, the use of PP duct equipment maintenance frequency than the use of metal duct equipment reduced by more than 50%, greatly improving production efficiency.

(ii) Sealing: “zero air leakage” guarantee

PP ducts are connected by heat fusion connection, flange connection and many other advanced connection methods. These connection methods can ensure that the ducts are tightly bonded to each other and realize “zero leakage” of air. In hospital operating rooms, good sealing is crucial. If there is leakage in the ventilation system, it will not only affect the air quality in the room, but may also lead to an increased risk of surgical infections. the excellent sealing of PP ducts can effectively prevent the leakage of harmful gases, providing a safe and clean environment for patients and healthcare workers. In industrial production, for some processes that require high gas purity, such as electronic chip manufacturing, the sealing of PP air ducts can ensure that the production environment is not interfered by external impurities, ensuring the stability of product quality.

(iii) Low noise: quiet ventilation system

PP material has good damping properties, which is the key to its noise reduction. As air flows through the duct, the PP material absorbs and attenuates sound waves, thus reducing the transmission of noise. Compared with metal ducts, PP ducts are significantly quieter in operation. According to professional tests, under the same conditions of air speed and air volume, the operation noise of metal ducts can be over 60 dB, while the noise of PP ducts can be controlled at about 40 dB, which is about 30% lower. In hospital wards, school classrooms and other noise-sensitive places, PP ducts can provide a quiet and comfortable environment, which is conducive to the recovery of patients and students’ learning.

(iv) Thermal insulation: energy saving and comfort

PP ducts can be equipped with specialized insulation, which effectively reduces heat loss. This feature is especially important in HVAC systems. In winter, PP square ducts with insulation can better retain heat in the room and reduce the energy consumption of heating equipment; in summer, it can prevent cold air from escaping and reduce the power consumption of air conditioning. Comparisons of real-world examples show that buildings with insulated PP ducts use 15% – 20% less energy for their HVAC systems than buildings with ordinary ducts. This not only saves energy costs for users, but also helps to reduce carbon emissions and realize green environmental protection.

(v) Long life: durable

PP material ages slowly, mainly due to its stable molecular structure and good chemical stability. Under normal operating conditions, PP ducts have a practical service life of 30 – 50 years. In some large industrial plants, PP ducts have been in continuous use for more than 30 years and are still performing well and do not need to be replaced. From a long-term cost perspective, although the initial investment in PP ducts may be slightly higher than some common ducts, the overall cost is lower due to their long service life and low maintenance costs. For example, while metal ducts require regular anti-corrosion treatment and repairs during use, PP ducts require little or no such additional costs, greatly reducing the operating costs of the enterprise.

Wind speed plays a key role in the determination of duct size, and there is a clear inverse relationship between it and the duct size. According to the formula for duct sizing (duct size = air volume / air velocity / 3600), the larger the air velocity, the smaller the calculated cross-sectional area of the duct for a fixed air volume of 20,000 m³/h; conversely, the smaller the air velocity, the larger the cross-sectional area of the duct.
The choice of different air velocities can affect the ventilation system in many ways. In terms of noise, a higher wind speed will lead to greater noise when the fan is running, and at the same time, the air flows at high speed in the duct, and when it passes through elbows, valves and other components, it is easy to generate airflow noise. For example, in some places with extremely high noise requirements, such as recording studios, libraries, etc., if a higher wind speed is used, the noise problem will seriously affect their normal use. Analyzing from the perspective of energy consumption, the higher the wind speed, the greater the resistance of the wind flowing in the duct, and in order to overcome these resistances, the fan needs to consume more electricity, thus increasing the operating cost of the system. In large commercial buildings, the ventilation system runs all day long, and if the wind speed is unreasonable leading to high energy consumption, it will generate a considerable amount of money in the long run. In addition, the wind speed will also affect the uniformity of ventilation, too high wind speed may lead to uneven distribution of air in the room, localized areas of under-ventilation or over-ventilation .

(二) Impact of system pressure

System pressure is another important factor that governs duct sizing. In a ventilation system, pressure is divided into static and dynamic pressure, with static pressure used to overcome the resistance of the duct and dynamic pressure related to the flow rate of the air . When the system pressure is high, it means that the duct needs to withstand a greater pressure load, which requires the duct to have enough strength and sealing to prevent the duct from rupturing or leaking .
In general, ducts in high-pressure systems require thicker, stronger materials. For example, in industrial ventilation, some air ducts conveying high-temperature and high-pressure gases may be made of steel plates of greater thickness and more stringent in terms of the connection parts of the air ducts and reinforcement measures . For low-pressure systems, the strength requirements of air ducts are relatively low, and thinner materials can be used, so as to meet the operational requirements of the system and reduce costs. If air ducts that do not meet the pressure requirements are used in high-pressure systems, it may lead to deformation and rupture of air ducts, which not only affects the ventilation effect, but also may cause safety accidents.

(三) Impact of usage scenarios and demand

Different scenarios and needs have different requirements for the size of the 20000 air volume ducts. In industrial plants, due to the large space and relatively low sensitivity to noise, in order to save cost and space, a higher air velocity is usually used, and the corresponding duct size can be smaller. For example, in some large-scale machinery processing plants, the air velocity of the main duct of the ventilation system may reach 10m/s or even higher, so that the cross-sectional area of the duct can be designed to be relatively small under the circumstance of meeting the 20,000 air volume.
Commercial buildings such as shopping malls and supermarkets are densely populated and have high requirements for indoor air quality and comfort, and also need to consider the impact of noise on the shopping experience of customers. Therefore, the air velocity of the ventilation system in such places is generally controlled in a moderate range, such as 6 – 8m/s, and the size of the air ducts will be designed according to the specific layout and air volume distribution. Moreover, commercial buildings usually have decorative structures such as suspended ceilings, and the installation of air ducts needs to be coordinated with the building structure, which also affects the selection of air duct sizes.
Residential ventilation systems are relatively small, but the requirements for noise are more stringent, because noise can directly affect the quality of life of residents. In residential houses, even if the airflow reaches 20,000 (which is relatively rare, and generally the airflow of residential houses is small, but assuming special circumstances), a lower air velocity, such as 4 – 6m/s, will be used to ensure a quiet living environment . In this case, in order to meet the demand for airflow, the size of the ducts may be relatively large, but the space of the house is limited, which requires full consideration of the layout and installation location of the ducts in the design, to minimize the occupation of indoor space.

1.Metal ducts: common metal ducts include galvanized steel ducts, stainless steel ducts and aluminum ducts. Galvanized steel duct price is relatively low, has good mechanical strength and fire performance, the most widely used, in general industrial and civil building ventilation system can see its figure. Stainless steel ducts have excellent corrosion resistance and are suitable for chemical, food and other industries with high requirements for hygiene and corrosion resistance, such as the ventilation ducts of food processing plants, stainless steel ducts are often used to ensure the purity of the air and the durability of the ducts. Aluminum plate duct is lightweight and not easy to produce sparks when collision, so it will be used in places with explosion-proof requirements, such as coal mine underground ventilation system.

2.Composite duct: Composite duct is made of a variety of materials composite, generally including thermal insulation materials and surface materials. For example, phenolic composite duct, it is phenolic foam as the core material, the surface covered with aluminum foil and other materials, with lightweight, good thermal insulation performance, sound insulation effect, etc., commonly used in the air conditioning and ventilation system with high requirements for thermal insulation and sound insulation, such as hotels, office buildings, central air conditioning ducts. There is also glass-magnesium composite air duct, which has excellent fireproof performance and high strength, and is used more in some buildings with strict fire safety requirements, such as shopping malls, hospitals and other places.

3.Polymer duct: Polymer duct is made of polymer material, such as polyvinyl chloride (PVC) duct, PVC duct has the characteristics of strong corrosion resistance, low price, easy installation, etc., which is widely used in some industrial places with corrosive gas emission, such as the ventilation system of electroplating workshop. However, PVC ducts have poor high temperature resistance and relatively narrow temperature range.

How to size ducts for 20000 air volume.

1.Assumed air velocity method
The assumed wind speed method is a common and relatively simple calculation method for determining the duct size required for 20,000 airflow. The core formula is: duct size (cross-sectional area) = air volume / air velocity / 3600. The principle of this formula is based on the relationship between flow rate, velocity and time. The unit of air volume is usually cubic meters per hour (m³/h), which indicates the volume of air passing through the duct in a unit of time; the unit of wind speed is meters per second (m/s), which describes the speed of air flowing through the duct; and 3600 is the conversion factor for converting hours to seconds, which gives the cross-sectional area of the duct in square meters (m²).
When applying this, it is first necessary to make reasonable assumptions about the wind speed. The choice of wind speed is not arbitrary, but to consider a variety of factors. For example, in the civil building ventilation system, if the noise control requirements are high, the wind speed should not be too large, generally the main duct wind speed can be controlled at 4 – 7m / s; in industrial plants and other relatively low noise requirements of the place, in order to reduce the size of the duct, reduce costs, the main duct wind speed can be increased appropriately, such as 6 – 12m / s . Suppose we have to determine the duct size for 20000m³/h airflow in an industrial project with general noise requirement, assuming the air velocity is 8m/s. According to the formula, the cross-sectional area of the duct = 20000÷8÷3600 ≈ 0.694m².
If a circular duct is used, we can further calculate the duct diameter according to the formula of the area of a circle S = πr² (where S is the area and r is the radius). From 0.694 = 3.14×r², we can get r² = 0.694÷3.14 ≈ 0.221, r ≈ 0.47m, then the diameter d = 2r ≈ 0.94m. If you choose rectangular duct, you also need to determine the ratio of length and width according to the actual installation space and design requirements, assuming that the ratio of length and width of 2:1, set the width of x meters, then the length of 2x meters, 2x × x = 0.694, that is, 2x ² = 0.694, can be obtained x ² = 0.347, x ≈ 0.59m, then the length of 2x ≈ 1.18m, that is, the size of the rectangular air duct can be 1180mm × 590mm.

2. Introduction to other calculation methods
In addition to the assumption of wind speed method, there are also a variety of methods to calculate the size of the duct, such as specific resistance method, area method, flow coefficient method. Specific resistance method is to calculate the friction resistance per unit length of the duct (specific resistance), combined with the total resistance of the duct and the air volume to determine the size of the duct, this method of calculation is relatively complex, you need to consider more resistance factors, such as the roughness of the duct, air viscosity, and so on. Area method is based on the known cross-sectional area of the duct and wind speed to calculate the air volume, and the assumption of wind speed method of calculation of the opposite idea, in the known air inference duct size, you need to determine the appropriate size through a number of trial calculations. Flow coefficient method is based on the flow coefficient of the inlet or outlet of the duct, combined with the wind speed and cross-sectional area to calculate the air volume, the method needs to know the flow coefficient of the duct in advance, and the flow coefficient is usually provided by the manufacturer or determined by experiments.
However, in practical engineering applications, the assumed air velocity method is most commonly used because it is relatively simple and intuitive to calculate, and can meet the accuracy requirements of most projects. In this discussion on 20000 air volume duct sizing, we also focus on the assumed air velocity method as an example to analyze and calculate, so that we can understand and grasp the basic method of duct sizing more clearly.

In the ventilation system of all kinds of buildings, the suitability of air volume and duct size is crucial, which is directly related to the ventilation effect, energy consumption and the stability of the operation of the whole system. Imagine a large shopping mall or factory, if the ventilation system duct size is unreasonable, either can not meet the indoor ventilation needs, resulting in dirty air, stuffy, affecting people’s comfort and work efficiency; or will cause energy waste, increase operating costs. Today, we focus on a specific problem: when the air volume is 20000, how big should the air duct be? This seemingly simple question involves a series of complex calculations and consideration of various factors. Let’s dig deeper and solve the mystery for you.

二.Duct Basics

(1) Role of air ducts

Duct, as a key component of the ventilation system, undertakes the important mission of conveying and distributing air . In the ventilation system, it is like the trachea in the human body’s respiratory system, which is the channel for air circulation. Fresh air is introduced into the room through the air ducts to provide people with sufficient oxygen and maintain a comfortable indoor environment; at the same time, indoor dirty air, harmful gases, and excess heat and moisture, etc., also rely on the air ducts to be discharged outdoors to ensure indoor air quality and hygiene. For example, in the operating room of a hospital, the air duct continuously sends in purified sterile air and discharges the exhaust air that may carry germs to create a safe air environment for the smooth operation; in the factory workshop, the air duct can timely discharge the dust, smoke and other harmful pollutants produced during the production process to protect the health of the workers.

（2）Classification of air ducts（Classified by cross-section shape）

• Round Duct: Round duct has superior aerodynamic performance, air flows in it with minimum resistance, which makes the round duct can effectively reduce the energy consumption of the fan under the same air volume, and the operation cost is lower. At the same time, it has good sealing performance, which can reduce air leakage and ensure the efficient operation of the ventilation system. Circular air ducts are widely used in places with high ventilation requirements and where space permits, such as the central air conditioning ventilation system of large shopping malls. However, the production process of round air duct is relatively complicated and occupies a large space height, so the installation may be restricted in some buildings with limited space.

• Rectangular Duct: The biggest advantage of rectangular duct is that it can better adapt to the building structure and combine closely with the walls and ceilings of the building, which makes it easy to install and layout. In most office buildings, residential and other places, due to the characteristics of the space layout, rectangular duct is more common. It is relatively simple to fabricate, and the fittings are easy to make and connect. However, the air resistance of rectangular duct is relatively large, in the case of conveying the same amount of air, it requires a more powerful fan, and the energy consumption will increase accordingly, and its air leakage rate is relatively high.

• Flat round duct: Flat round duct combines part of the characteristics of round duct and rectangular duct, it reduces the height size of round duct to some extent, and less resistance than rectangular duct. In some of the space height has some limitations, but also on the ventilation resistance requirements of the occasion, such as some of the lower level underground parking lot ventilation system, flat round air duct can play its advantage. However, the production difficulty of flat round duct is between round and rectangular duct, the application scope is relatively narrow.

Translated with DeepL.com (free version)

Product Name: Copolymer type PP materials have lower heat distortion temperature (100°C), low transparency, low gloss, low rigidity, but have greater impact strength.The strength of PP increases with increasing ethylene content.The Vicat softening temperature of PP is 150°C. The Vicat softening temperature of PP is 150°C. The Vicat softening temperature of PP is 150°C. The Vicat softening temperature of PP is 150°C. The Vicat softening temperature of PP is 150°C. Due to the high degree of crystallinity, this material has good surface stiffness and scratch resistance properties.PP does not suffer from environmental stress cracking. Typically, PP is modified by adding glass fibers, metal additives, or thermoplastic rubber.The flow rate MFR of PP ranges from 1 to 40.PP materials with low MFR have better impact characteristics but lower ductile strength. For the same MFR, the copolymer type is stronger than the homopolymer type. Due to crystallization, the shrinkage of PP is quite high, generally 1.8 to 2.5%. And the directional uniformity of shrinkage is much better than materials such as PE-HD. Adding 30% glass additive can reduce the shrinkage to 0.7%. Both homopolymer-type and copolymer-type PP materials have excellent resistance to moisture absorption, acid and alkali corrosion, and solubility. However, it has no resistance to aromatic hydrocarbon (e.g., benzene) solvents, chlorinated hydrocarbon (carbon tetrachloride) solvents, etc. PP also does not have oxidation resistance at high temperatures like PE.

Plate Classification

• Pure PP sheet

Small density, easy to weld and process, with superior chemical resistance, heat resistance and impact resistance, non-toxic, tasteless is the most environmentally friendly requirements of one of the engineering plastics. The main colors are white, microcomputer color, other colors can also be customized according to customer requirements. Applications: Acid and alkali resistant equipment.

• Polypropylene (PP) Extrusion Sheet

It is a plastic sheet made of PP resin added with various functional additives through extrusion, calendaring, cooling, cutting and other processes.

• Glass Fiber Reinforced PP Sheet

Glass fiber reinforced PP board (FRPP board): After 20% glass fiber enhancement, in addition to maintaining the original excellent performance, strength, rigidity, etc. are doubled compared with PP, and has good heat resistance, low temperature impact, corrosion resistance to arc, low shrinkage. Especially suitable for chemical fiber, chlor-alkali, petroleum, dyes, pesticides, food, medicine, light industry, metallurgy, sewage treatment and other fields.

PPH sheet, Beta (β)-PPH single side laminated nonwoven sheet. (β)-PPH products have excellent heat and oxygen aging resistance, long service life, and good mechanical properties. It has been successfully used in the production of plates, and the advanced technology is among the leading ones in China. These products can be used for filter plates and spiral-wound containers, for FRP winding liner plates, for storage, transportation and anti-corrosion systems in the petrochemical industry, for water supply, water treatment and drainage systems in power plants and waterworks, and for dust removal, scrubbing and ventilating systems in steel mills and power plants.

Characteristics and Uses

PP extrusion sheet has light weight, uniform thickness, smooth and flat surface, good heat resistance, high mechanical strength, excellent chemical stability and electrical insulation, non-toxicity, etc. PP sheet is widely used in chemical containers, machinery, electronics, electrical appliances, food packaging, pharmaceuticals, decoration and water treatment, etc. The practical temperature of PP sheet can reach 100 degrees.

Scope of Application

Acid and alkali resistant equipment, electroplating equipment, solar photovoltaic equipment, environmental protection equipment, wastewater, waste gas discharge equipment, washing tower, clean room, semiconductor plant and its related industrial equipment, is also the first choice of material for the manufacture of plastic water tanks, which PP thick plate is widely used in stamping plate, press pads and so on.

1. advertising signboards;
2. Recycling bins, including reusable recycling bins for various industries, fruit and vegetable packing bins, clothes storage bins, stationery bins;
3. industrial boards, including wire and cable outer wrapping protection, glass, steel plate, all kinds of articles outer wrapping protection, padding board, shelf, partition board, bottom board, etc;
4. protection board, cardboard, three clipboard protection construction of building materials in the era of gone, with the progress of the times and taste, to ensure that the integrity of the decorative design in the completion of the opening of the completion, should be given appropriate protection in order to maintain the operation of the economy, safety and convenience, and other building elevators, flooring before acceptance of the protection.
5. Electronic industry protection. Conductive packaging products are mainly used in IC wafers, IC packaging, testing, TFT-LCD, optoelectronics and other electronic parts of the packaging, the purpose is to avoid other charged items in contact with them, resulting in parts due to charge friction spark damage. There are also conductive, anti-static plastic plates, crates and so on. 　PP board can be used in addition to the above products, but also used in washing machine backplane, refrigerator insulation layer, frozen food, medicine, sugar and wine packaging. Can also use the hollow plate production line to produce PE hollow plate to supply urban construction, rural areas need to keep the greenhouse partition.

1. Mechanical cutting

Mechanical cutting is one of the common ways of cutting plates. This method mainly uses a cutting machine or punch press to cut the sheet through the action of mechanical force. The operation requires precise adjustment of the position of the cutter and the depth of cut to ensure accurate and smooth cutting. The advantage of mechanical cutting is that it is easy to operate, suitable for mass production and relatively low cost.

2. Laser cutting

Laser cutting is a high-precision method of cutting plates. It uses a high-power laser beam to irradiate the sheet, causing it to melt or carbonize locally, and then blow the melted material away from the sheet through airflow or mechanical force, thus realizing cutting. The advantages of laser cutting are high cutting precision, high speed and suitable for cutting complex shapes.

3. Thermal cutting

Thermal cutting is mainly to soften the sheet by high temperature, and then use mechanical force or blade to cut. This method is suitable for thicker plates. The advantage of thermal cutting is that it is suitable for different thicknesses of plates, but the operation needs to pay attention to the control of the temperature, to avoid overheating caused by the deformation of the plate.

When carrying out plate cutting, the following points should also be noted:

1. choose suitable cutting tools and equipment, according to the thickness and hardness of the sheet.
2. keep safe when operating, wear protective glasses and gloves to avoid splash injury.
3. make sure the surface of the plate is clean and free of impurities before cutting to improve the cutting quality.

The welding method of PP sheet mainly includes the following steps:

1. Preparation: Before welding, you need to make sure that the welding tools are functioning properly. Check whether the nozzle of the welding gun and the screws of the gun body are loose or off, and connect the power cord of the welding apparatus to ensure that the power supply is not loose.
2. .Pre-welding treatment: Wipe the PP sheet clean and make sure the welding area is dry and free of dust and grease. In addition, it is also necessary to chamfer the edges of the PP sheet.

Welding Sequence:

1. Use hot gas welding or a torch for welding. Hot gas welding can be done with an inert gas such as air or nitrogen; the gas must be dry and free of dust and grease.
2. Clamp the two PP sheets with a fixture to ensure the correct welding position. When welding, hold the welding tool in one hand and press the welding rod into the weld area with the other hand.
3. The welding torch and the object to be welded make an angle of 45 degrees and push the welding rod at a constant speed, while the welding torch moves along the connecting axis in the form of a pendulum to ensure the quality of welding.
4. During the welding process, the welding pressure needs to be controlled to avoid too light or too heavy, so as not to affect the welding effect.

After welding: after welding is completed, first put the welding torch on the workbench, cut off the power supply, clean up the workplace, and finally put the welding tools and materials back to their original places.

Things to keep in mind during the welding process include:Ensure that the welding electrode is the same as the base material to obtain the best weld strength.
Adjust the temperature of the welding torch between scale 3-4 to avoid too high or too low temperatures, which may affect the quality of the weld.
Weld quality is dependent on the welder’s skill and ability to control welding pressure.

1.Basic properties of PPH

• Chemical resistance: PPH has strong resistance to a variety of chemicals and is not easily corroded by acids and alkalis.
• Good mechanical properties: high strength and rigidity, while maintaining good toughness.
• Excellent heat resistance: able to maintain stable performance at higher temperatures, with a high melting point.
• Lightweight: low density, light weight, easy to process and transport.
• Good electrical insulation: suitable for electrical and electronic applications.

2.Application areas of PPH

• Packaging industry: Since PPH material is non-toxic and odorless, and has good thermal stability and moisture resistance, it is often used for packaging of food, medicine and other products.
• Automotive industry: PPH’s impact resistance and corrosion resistance make it an ideal material for automotive interior and exterior parts, such as bumpers and instrument panels.
• Home appliance field: The shells and parts of household appliances such as washing machines and refrigerators are also often made of PPH, as it can meet the strength requirements as well as aesthetics.
• Medical industry: PPH is also used to manufacture medical devices and containers due to its biocompatibility and chemical stability.
• Piping system: PPH pipes are widely used in chemical industry, water supply, drainage and other fields due to its corrosion resistance, high strength and long life.

3.PPH processing method

PPH materials can be processed by injection molding, extrusion, blow molding and other methods. During processing, attention needs to be paid to the control of temperature and pressure to ensure the quality and performance of the products.

4.Summary

As a high-quality homopolymerized polypropylene material, PPH has a wide range of applications in many fields due to its excellent physical and chemical properties. With the advancement of science and technology and the improvement of environmental protection awareness, the application prospect of PPH will be even broader. Whether in packaging, automotive, home appliances or medical fields, PPH has demonstrated its unique advantages and potential.

PPH sheets can also be used in the following applications

1.Water treatment field: PPH sheet is excellent in the field of water treatment, because of its excellent corrosion resistance, high temperature resistance and good mechanical properties, commonly used in the manufacture of reactors, tanks, pipelines and other equipment. In the field of municipal sewage treatment, water reuse, PPH sheet equipment can effectively remove impurities and harmful substances in the water, to protect the safety of water quality.

2.Waste gas treatment field: PPH sheet is also outstanding in waste gas treatment, suitable for dealing with waste gas containing corrosive gases and high temperature gases. For example, in the chemical industry, metallurgy and other industries in the waste gas treatment, PPH material waste gas scrubber tower, absorption tower and other equipment can effectively remove harmful substances in the waste gas, reduce environmental pollution.

3.Solid waste treatment field: PPH sheet also has important applications in solid waste treatment, can be used to manufacture a variety of storage tanks, conveying piping and other equipment. In the utilization of solid waste resources, PPH sheet equipment can be used to deal with waste leachate, sludge and other wastes, through physical, chemical or biological methods into valuable resources.

4.New energy field: With the development of new energy industry, PPH sheet is used in the solar photovoltaic industry to manufacture solar collectors, solar water storage tanks and other equipment to improve the efficiency of solar energy utilization. In the wind energy industry, PPH sheet is used to manufacture wind turbine cooling system, lubrication system and other equipment, to ensure the normal operation of wind turbines

5.Other fields: PPH sheet is also used in irrigation systems, greenhouses and other equipment in the field of agriculture to improve the efficiency of agricultural production. In the field of environmental protection monitoring, PPH sheet equipment is used to monitor environmental quality