HDPE pipe and fitting,PVC pipe and fitting

Due to its unique material properties and manufacturing process, HDPE (high-density polyethylene) pipe has become the preferred material in the field of environmental protection. The main reasons include the following aspects:

 

1. The material is non-toxic and recyclable

High chemical stability: HDPE is non-toxic, odorless, does not contain heavy metals or harmful additives, will not pollute water quality, and meets drinking water and food grade standards (such as FDA, NSF certification).

100% recyclable: HDPE can be melted and recycled many times, and can still maintain its performance after recycling, reducing the amount of plastic waste landfill and supporting the circular economy.

 

2. Energy-saving and low-carbon production process

 

Low-temperature processing: The melting temperature (about 160°C) of HDPE pipe production is much lower than that of materials such as metal or glass, and the energy consumption is lower.

Lightweight: The weight is only 1/8 of that of metal pipes, and the energy consumption for transportation and installation is greatly reduced, reducing carbon emissions.

 

3. Extraordinary life and durability

Corrosion and aging resistance: resistant to acid, alkali, salt, and microbial erosion, no anti-corrosion coating required, life of more than 50 years, reducing replacement frequency and resource waste.

Strong impact resistance: good flexibility, resistant to ground subsidence and earthquake, reducing the risk of leakage pollution caused by rupture.

 

4. Reducing resource consumption

Replacing traditional materials: It can replace high-energy-consuming materials such as cement pipes and cast iron pipes, and the production of 1 ton of HDPE pipes saves about 75% of energy compared to metal pipes.

High construction efficiency: hot-melt connection does not require chemical adhesives to avoid secondary pollution, and the joints have good sealing to prevent leakage.

 

5. Ecological protection advantages

Non-leakage design: HDPE pipeline system has excellent sealing to avoid sewage or chemical leakage to pollute soil and groundwater.

Application of renewable raw materials: Some HDPE pipes use bio-based polyethylene (such as ethylene extracted from sugarcane ethanol), further reducing dependence on fossil resources.

 

6. Environmental contribution of application scenarios

Rainwater collection and recycled water utilization: widely used in sustainable drainage systems (SUDS) and water reuse projects.

Landfill anti-seepage: used as a liner to prevent leakage of harmful substances.

Marine engineering: resistant to salt spray corrosion, can be used in eco-friendly offshore facilities.

 

Environmental disadvantages compared with other materials

PVC pipes: may contain plasticizers (such as phthalates), and incineration will produce dioxins.

Metal pipes: easy to rust, high energy consumption in production, and mining damages the ecological environment.

 

HDPE pipes have environmental advantages throughout their life cycle from raw materials, production, use to recycling, and are in line with global sustainable development goals (such as SDGs). They are particularly outstanding in the fields of water conservation, energy conservation and pollution prevention and control, making them the green first choice for municipal, industrial and agricultural projects.

Official website: www.phtopindustry.com | www.phpipes.com
Contact us: Email:inquiry@phtopindustry.com | Whatsapp:+86 15093100892
Company address: Room 802, 8th Floor, Building 5, Jinyin Modern City, Jinshui District, Zhengzhou City, Henan Province, China

 

HDPE pipes (high-density polyethylene pipes) are widely used in agricultural irrigation due to their corrosion resistance, aging resistance, good flexibility, and convenient construction. Reasonable selection of pipe diameter and pressure level can effectively improve irrigation efficiency, reduce costs, and extend service life. This article will systematically introduce the selection method of HDPE pipes in agricultural irrigation from three aspects: selection principle, diameter calculation, and pressure level determination.

 

Selection principle

1. Meet the irrigation flow demand

The pipe diameter must ensure sufficient flow to avoid excessive hydraulic loss due to too small a diameter, which will affect the irrigation effect.

2. Ensure water delivery pressure

According to the terrain height difference, pipe length, and terminal equipment requirements, reasonably select the pressure level to avoid pipe bursting or insufficient water pressure.

3. Take into account economy

The larger the diameter, the higher the investment. It is necessary to optimize the pipe size and reduce the construction and operation costs on the premise of meeting the use requirements.

 

Calculation method for HDPE pipe diameter

1. Basic formula

Common flow-velocity formula for irrigation system to calculate pipe diameter:

Q=A×VQ = A \times VQ=A×V

Where:

Q = flow (m³/s)

A = pipe cross-sectional area (m²), A = π × (D/2)²

V = flow velocity (m/s)

2. Recommended flow velocity

Pipe Diameter Range	Recommended Flow Velocity (m/s)	Remarks
D < 100mm	0.6 - 1.5	Low velocity for small diameters to avoid water hammer
100mm ≤ D ≤ 300mm	1.0 - 2.0	Moderate velocity for medium diameters
D > 300mm	1.2 - 2.5	Higher velocity allowed for large diameters

3. Diameter calculation example

Assuming the design flow rate is 50m³/h, convert to m³/s:

Q=503600≈0.0139 m3/sQ = \frac{50}{3600} ≈ 0.0139 \, m³/sQ=360050?≈0.0139m3/s

Take the design flow rate V = 1.5 m/s, then the pipe cross-sectional area:

A=QV=0.01391.5≈0.00927 m2A = \frac{Q}{V} = \frac{0.0139}{1.5} ≈ 0.00927 \, m²A=VQ?=1.50.0139?≈0.00927m2

Calculate the inner diameter D:

D=2×Aπ=2×0.009273.1416≈0.1085 m≈110mmD = 2 \times \sqrt{\frac{A}{\pi}} = 2 \times \sqrt{\frac{0.00927}{3.1416}} ≈ 0.1085 \, m ≈ 110mmD=2×πA??=2×3.14160.00927??≈0.1085m≈110mm

Therefore, DN110 HDPE pipe is recommended.

 

HDPE pipe pressure level selection

1. Common nominal pressure (PN) levels

Nominal Pressure (PN)	Maximum Working Pressure (MPa)	Application Scenario
PN6	0.6 MPa	Gravity flow, low-pressure water conveyance
PN10	1.0 MPa	General farmland irrigation
PN12.5	1.25 MPa	Undulating terrain, medium to long-distance water transport
PN16	1.6 MPa	Large elevation differences or sprinkler systems
PN20	2.0 MPa	High-pressure main water supply pipelines

2. Pressure verification formula (Hagen-William formula)

Hf=10.67×L×Q1.85C1.85×D4.87H_f = 10.67 \times \frac{L \times Q^{1.85}}{C^{1.85} \times D^{4.87}}Hf?=10.67×C1.85×D4.87L×Q1.85?

H_f = Head loss along the way (m)

L = Pipeline length (m)

Q = Flow rate (L/s)

C = Hagen-William roughness coefficient (HDPE takes 150)

D = Pipeline inner diameter (mm)

According to the water source pressure, head and terminal equipment requirements, after verifying the head loss, select the appropriate pressure level.

 

Summarize the selection process

Determine the design flow (based on the irrigation area, irrigation method, etc.).

Select a reasonable flow rate (based on pipe diameter and system type).

Calculate the pipe diameter (to ensure sufficient flow and economic rationality).

Calculate the head loss based on the terrain and pipe length.

Determine the pressure level (to meet safety and operation requirements).

Comprehensively consider cost and installation convenience to optimize the selection.

Official website: www.phtopindustry.com | www.phpipes.com
Contact us: Email:inquiry@phtopindustry.com | Whatsapp:+86 15093100892
Company address: Room 802, 8th Floor, Building 5, Jinyin Modern City, Jinshui District, Zhengzhou City, Henan Province, China

 

HDPE pipes (high-density polyethylene pipes) are widely used in the field of gas transportation. Due to their superior performance and high safety, they have gradually replaced traditional metal pipes. The following is a detailed description of the advantages and safety standards.

Advantages of HDPE pipes in gas transportation

1. Excellent corrosion resistance

HDPE pipes have strong corrosion resistance to chemicals such as acids, alkalis, and salts. They are particularly suitable for buried gas pipeline systems, avoiding the risk of metal pipelines being easily rusted and leaked, and extending their service life.

2. Good flexibility and seismic resistance

HDPE pipes have good flexibility and impact resistance, can adapt to geological movements such as ground subsidence and earthquakes, reduce the probability of pipeline breakage and loose interfaces, and ensure the continuity and safety of gas transportation.

3. Reliable connection and no leakage

HDPE gas pipes mostly use hot-melt butt or electric fusion connection technology. The welding part is integrated with the parent material, and the connection strength is higher than the pipe body, ensuring that the pipeline system is leak-free and significantly improving the operation safety.

4. Lightweight and easy to construct

Compared with traditional metal pipes, HDPE pipes are lighter, easier to transport and lay, and can be supplied in coil form, which reduces the number of interfaces, shortens the construction period, and reduces engineering costs.

5. Excellent aging resistance and service life

HDPE gas pipes are added with anti-ultraviolet and anti-aging additives, and have a service life of more than 50 years (under normal temperature and pressure conditions), greatly reducing the frequency and cost of subsequent maintenance.

6. Good fluid transportation performance

The inner wall of HDPE pipes is smooth, with low friction resistance and a larger flow rate under the same caliber, saving energy transportation costs and improving gas transportation efficiency.

 

Safety standards for HDPE gas pipelines

1. ISO 4437 standard

Internationally, HDPE gas pipelines mainly follow the ISO 4437 standard, which regulates the materials, performance, test methods and use requirements of polyethylene (PE) pipeline systems for gas transportation, ensuring the safety and reliability of the pipelines.

2. China National Standard GB 15558

In China, HDPE gas pipelines implement "GB 15558.1-2015 Buried Polyethylene (PE) Pipeline System for Gas Part 1: Pipes", which strictly stipulates the raw materials (PE80, PE100), pipeline pressure levels, dimensions, tolerances, and physical properties (resistance to hydrostatic pressure, resistance to slow crack growth, resistance to rapid crack expansion, etc.).

3. ASTM D2513 (American standard)

American HDPE pipes for gas follow the ASTM D2513 standard, covering the classification of pipes, material requirements, physical properties, connection methods and pressure testing, ensuring the safe application of pipelines.

4. Safe operation specifications

Construction standards: HDPE gas pipe construction must follow standardized operations, such as the "Gas Pipeline Engineering Construction and Acceptance Specifications" (GB 50251-2015), to ensure welding quality, laying depth, and protective measures are in place.

Inspection and acceptance: including pressure testing, welding quality testing, flaw detection, etc., to ensure that there is no leakage and no defects before it can be put into use.

Regular inspection and maintenance: According to the gas company and industry specifications, regular pipeline inspections, inspections, and preventive maintenance are carried out to ensure long-term safe operation.

 

HDPE pipe has become the preferred material for gas transportation with its excellent corrosion resistance, flexibility, leak-free connection method and long life. At the same time, perfect international and domestic safety standards provide a strong guarantee for the safe operation of HDPE gas pipelines. With the continuous development of urban gas pipeline networks, HDPE pipes will play a more important role in the field of gas transportation.

Official website: www.phtopindustry.com | www.phpipes.com
Contact us: Email:inquiry@phtopindustry.com | Whatsapp:+86 15093100892
Company address: Room 802, 8th Floor, Building 5, Jinyin Modern City, Jinshui District, Zhengzhou City, Henan Province, China

 

High-density polyethylene (HDPE) pipes have been widely used in the field of municipal engineering due to their excellent corrosion resistance, flexibility, connection reliability and long service life, especially in water supply and drainage, gas, power sheathing and sewage treatment systems. However, HDPE pipes still need to strictly follow the specifications during installation to ensure the quality of the project and the safety and stability of pipeline operation.

 

Preparation before construction

1. Material acceptance: Confirm that the HDPE pipes and fittings used meet the design and national standards, and check whether there are cracks, scratches, deformation and other defects on the surface of the pipe.

2. Construction site inspection: Clean the construction site to ensure that the foundation is flat and there are no sharp stones or hard objects to prevent damage during pipeline laying.

3. Equipment preparation: Prepare corresponding Pipe Welding Machine#mce_temp_url#, hot melt sleeve machine, electric melting machine according to the scale of the project.

 

Key points for installing HDPE pipes

1. Correct handling and storage:

Handle with care during handling to avoid severe impact and falling.

Place the pipe on a flat surface during storage to avoid long-term direct sunlight and heavy pressure.

2. Selection of pipe connection method:

Butt-melt: Suitable for the connection of large-diameter straight pipes. The welding surface must be kept clean, and the welding temperature and pressure must meet the standards.

Electrofusion connection: Suitable for connection with limited space or special pipe fittings. The welding surface should be cleaned before connection, and the operation should be strictly carried out in accordance with the parameters provided by the electrofusion pipe fitting manufacturer.

Flange connection: Suitable for connection with metal pipes or equipment interfaces. Sealing gaskets should be used to tighten the bolts evenly.

3. Pipeline laying and backfilling:

Pipeline laying should be straight and stable, and the turning point should be constructed according to the minimum bending radius to prevent damage caused by forced bending.

Backfill soil should be compacted in layers. It is forbidden to directly roll the top of the pipe with large machinery to avoid local pressure causing pipe deformation.

 

Issues to be noted during construction

1. Temperature influence:

HDPE materials are greatly affected by temperature. During winter construction, the heating and cooling time should be appropriately extended, and in summer, overheating and deformation should be prevented.

2. Welding quality control:

After each welding, the flatness and uniformity of the weld should be checked, and the welding strength test should be performed if necessary to ensure that the welding is firm and reliable.

3. Prevent foreign matter from entering the pipeline:

During the installation process, the pipeline opening should be temporarily blocked to prevent mud and debris from entering and affecting subsequent use.

 

Completion acceptance and pressure test

Pressure test: After the installation is completed, a water pressure or air pressure test should be carried out according to the specifications to check the sealing and pressure bearing capacity of the pipeline system.

Inspection of the interface between the inspection well and the pipeline: Ensure that the interface between the inspection well and the pipeline is tight and there is no leakage.

Completion data is complete: including construction records, welding records, pressure test records, etc., to provide guarantees for subsequent operation and maintenance.

 

Later maintenance suggestions

Regularly check the operation of the pipeline, focusing on the ground settlement area and the interface.

For areas with shallow burial depth and large external force influence, protective measures can be added to extend the service life.

 

The application of HDPE pipes in municipal engineering not only improves the durability and economy of the pipe network, but every detail in the installation process cannot be ignored. Scientific and standardized construction management is the key to ensuring the long-term safe operation of the HDPE pipe system.

Official website: www.phtopindustry.com | www.phpipes.com
Contact us: Email:inquiry@phtopindustry.com | Whatsapp:+86 15093100892
Company address: Room 802, 8th Floor, Building 5, Jinyin Modern City, Jinshui District, Zhengzhou City, Henan Province, China

 Pipe Welding Machine

HDPE (high-density polyethylene) pipes are widely used in water supply and drainage, gas transmission and other fields due to their corrosion resistance, good flexibility and long life. Electrofusion welding is one of the common connection methods for HDPE pipes, but various problems may be encountered in actual construction. This article will introduce the common problems, cause analysis and solutions in electrofusion welding in detail to help improve the construction quality.

 

Basic principles of electrofusion connection

Electrofusion connection is to heat the HDPE material through the resistance wire inside the electrofusion sleeve (or electrofusion pipe fitting), and form a high-strength sealed joint after cooling. The key steps include:

Pipe end surface treatment (scraping oxide layer, cleaning)

Centering and fixing (avoid eccentricity)

Electric heating (control time and voltage according to manufacturer parameters)

Cooling and curing (natural cooling to avoid external interference)

 

Common problems and solutions

1. The electric fusion joint is not firm or leaking

Possible reasons:

The oxide layer on the pipe end surface is not scraped clean, resulting in poor fusion

The electric fusion time is insufficient or the voltage is unstable, and the melting temperature is not reached

External force disturbance during cooling

Electrofusion pipe fittings or pipe materials are unqualified (such as doped recycled materials)

Solution:

Strictly handle the pipe end surface:

Use a special scraper to remove the oxide layer (scraping length ≥ electric fusion sleeve insertion depth)

Wipe with alcohol or a clean cloth to ensure that there is no oil or dust

Control heating parameters:

Set the welding machine according to the voltage and time provided by the manufacturer (different pipe diameters and ambient temperatures need to be adjusted)

Use a stabilized power supply to avoid voltage fluctuations

Ensure sufficient cooling:

Cooling time ≥ specified value (usually 20-30 minutes)

It is forbidden to move the pipe or apply pressure during cooling

Select qualified materials:

Purchase HDPE pipes and electric fusion pipe fittings that meet GB/T 13663 standards

Avoid using inferior or recycled materials

2. Smoke or fire during electric fusion

Possible causes:

Resistance wire short circuit or local overheating

Electrofusion pipes damp or internal contamination

Input voltage too high

Solution:

Check the electric fusion pipes:

Before use, check whether the internal resistance wire is intact, without breakage or deformation

Before construction in a humid environment, use a hot air gun to dry the pipes

Control voltage:

Ensure that the output voltage of the welding machine is consistent with the nominal value of the pipe (usually 39.5±0.5V)

Avoid long-term overload power

Emergency treatment:

Immediately turn off the power, replace the pipes and re-weld them after cooling

3. The observation hole is not ejected or ejected unevenly

Possible causes:

Insufficient heating time, material is not fully melted

Insufficient pipe insertion depth or large deviation in centering

Ambient temperature is too low (such as winter construction)

Solution:

Adjust construction parameters:

Extend heating time in low temperature environment (refer to manufacturer"s low temperature welding parameters)

Ensure that the pipe insertion depth is aligned with the electric fusion sleeve mark

Check centering:

Use a clamp to fix the pipe to avoid eccentricity (deviation ≤10% wall thickness)

The ejection height of the observation hole should be uniform (generally protruding 1-3mm)

4. The internal diameter of the joint is reduced or blocked after electric fusion

Possible causes:

Excessive accumulation of molten material inside the joint

The pipe port is not chamfered, and the molten material does not flow smoothly

Solution:

Pre-treat the pipe port:

Use a chamferer to process a 15° groove after cutting

Ensure that there are no burrs on the inner wall of the pipe

Control the amount of fusion:

Avoid overheating (operate according to standard parameters)

Electrofusion connection is a key link in the HDPE pipe system, and quality problems may cause leakage or structural failure. The failure rate can be significantly reduced by standardizing operations (cleaning, alignment, parameter control), selecting qualified materials, and strengthening construction management.

Official website: www.phtopindustry.com | www.phpipes.com
Contact us: Email:inquiry@phtopindustry.com | Whatsapp:+86 15093100892
Company address: Room 802, 8th Floor, Building 5, Jinyin Modern City, Jinshui District, Zhengzhou City, Henan Province, China