PE drip tape and drip irrigation pipe

I. Definition and characteristics of PE drip tape and drip irrigation pipe

1. PE drip tape: PE drip tape is usually a flat strip pipe made of polyethylene material with drippers distributed on it at a certain interval. It has the following characteristics:

(1) Low cost: Compared with other irrigation equipment, the manufacturing cost of PE drip tape is relatively low and suitable for large-scale application. For example, in some small farmlands or cash crop planting areas, PE drip tape is widely used due to its price advantage.

(2) Easy installation: PE drip tape is light, soft, easy to lay and install. It can be flexibly arranged according to different terrains and planting needs without the need for complex installation equipment and technology.

(3) Local irrigation: Water is slowly dripped to the vicinity of the plant roots through the dripper to achieve local precision irrigation and reduce water evaporation and waste. This irrigation method can improve water utilization efficiency and meet the plant's demand for water.

2. PE drip irrigation pipe: PE drip irrigation pipe is a circular pipe, usually made of polyethylene material, with small holes or drippers on the wall for water discharge. Its characteristics include:

(1) Strong durability: Compared with drip irrigation tape, PE drip irrigation pipe is more durable and can withstand certain pressure and external impact. It is not easy to be damaged during long-term use and has a long service life.

(2) Uniform water discharge: Due to the structural design of the drip irrigation pipe, water can flow out more evenly from the small holes or drippers on the wall of the pipe, ensuring that the plants have a stable water supply.

(3) Wide range of applications: PE drip irrigation pipe is suitable for various terrains and planting patterns, including field crops, orchards, greenhouses, etc. Drip irrigation pipes of different specifications can be selected according to different irrigation needs.

II. Performance indicators of PE drip irrigation tape and drip irrigation pipe

1. Oxidation induction time: Oxidation induction time is an important indicator for measuring the antioxidant performance of PE drip irrigation tape and drip irrigation pipe. A large difference between the actual measured value of oxidation induction time and the standard value may indicate that there is a problem with the pipe quality. A longer oxidation induction time means that the pipe has better antioxidant ability, can resist oxidation aging during use, and extend its service life.

2. Carbon black content: Carbon black plays an important role in PE drip irrigation tapes and drip irrigation pipes. Carbon black can improve the UV resistance and aging resistance of the pipe, so that it can be used stably for a long time in the natural environment. Under normal use, the carbon black content item is the basic performance of the material and generally does not change significantly.

3. Ash content: The ash percentage content can reflect whether certain admixtures are added during the production process of the sample. If the ash content is too high, it may affect the performance and quality of the pipe6.

4. Elongation at break: Elongation at break is an indicator of the flexibility of the pipe. A higher elongation at break means that the pipe has better flexibility, can adapt to changes in terrain and external forces to a certain extent, and is not easy to break.

5. Longitudinal shrinkage rate: The longitudinal shrinkage rate reflects the dimensional stability of the pipe after heating. A lower longitudinal shrinkage rate means that the pipe is not easy to deform during use, ensuring the stability and reliability of the irrigation system.

Ⅲ. Construction technology points of PE drip irrigation tape and drip irrigation pipe

1. Preparation before hot melt: Before hot melt connection, it is necessary to check the PE drip irrigation tape and drip irrigation pipe to ensure that the surface of the pipe is clean and undamaged. At the same time, prepare hot melt equipment and tools, such as hot melt machine, cutting knife, etc.

2. Selection of hot melt connection method: According to different pipe diameters and construction requirements, different hot melt connection methods can be selected, such as butt hot melt, socket hot melt, etc. Butt hot melt is suitable for pipe connection with larger pipe diameter, and socket hot melt is suitable for pipe connection with smaller pipe diameter.

3. Hot melt PE pipe construction technology: When hot melt connection is performed, it is necessary to follow certain operating specifications. First, heat the pipe to a certain temperature to melt its surface. Then, quickly dock or insert the two pipes, maintain a certain pressure, and make the pipe connection firm. During the connection process, pay attention to controlling the heating temperature and time to avoid excessive heating and damage to the pipe.

4. Hot melt PE pipe construction quality inspection: After the construction is completed, the quality of the hot melt connection needs to be inspected. Mainly check whether the connection parts are firm and leak-free, whether the surface of the pipe is flat and deformed, etc. If quality problems are found, they should be dealt with in time.

IV. Aging resistance of PE drip irrigation tape and drip irrigation pipe

1. Natural exposure aging test: The aging resistance of the drip irrigation tape can be studied by subjecting the PE drip irrigation tape samples to natural exposure aging, and conducting mechanical properties, rheological properties and infrared spectrum test analysis on the samples before and after aging3. After 60 days of outdoor exposure, the tensile strength retention rate and elongation at break retention rate of the pure PE sample were 81% and 15.6% respectively, which had lost its use value; while after 120 days of outdoor exposure, the elongation at break retention rates of different samples were different. The sample with antioxidant, light stabilizer and carbon black compounded at the same time has the best aging resistance.

2. Effect of aging on performance: Aging will cause the mechanical properties of PE drip irrigation tape and drip irrigation pipe to decrease, such as tensile strength and elongation at break. In addition, aging will also affect the rheological properties of the pipe, such as torque retention rate. Through infrared spectrum test, it can be found that the carbonyl peak generated at 1757cm-1 of the sample after aging moves from 0# to 4# to low wavenumbers in sequence, and becomes weaker and weaker, which indicates that the chemical structure changes during the aging process.

V. Hydraulic performance of PE drip irrigation belt and drip irrigation pipe

1. Flow state analysis: The hydraulic performance test and analysis of PE drip irrigation pipe with an inner diameter of 20mm, a wall thickness of 1.36mm, a pressure bearing capacity of 0.2MPa, a hole spacing of 60cm, and a water outlet diameter of 0.6mm were carried out under low pressure conditions. The results show that under the working head of the test, without considering the influence of water flow disturbance at the outlet of the drip irrigation pipe, the water flow in the test drip irrigation pipe has two flow states: laminar flow and turbulent flow, but mainly laminar flow.

2. Calculation of head loss: There is a large error in calculating head loss using the traditional hydraulic empirical formula, which is 0-14.29% different from the actual situation. Therefore, in practical applications, it is necessary to calculate and analyze the head loss according to the specific situation to ensure the normal operation of the irrigation system.

VI. Construction technical points of PE drip tape and drip irrigation pipe

1. Water-saving irrigation: With the increasing shortage of water resources, water-saving irrigation has become more and more important. As an efficient water-saving irrigation equipment, PE drip tape and drip irrigation pipe can avoid almost all application losses, including drift, interception, evaporation and deep leakage. Compared with traditional irrigation methods such as flooding, drip irrigation can greatly improve water use efficiency and save water resources.

2. Increase crop yield: PE drip tape and drip irrigation pipe can achieve precise irrigation, directly transport water to the vicinity of plant roots, and meet the plant's demand for water. At the same time, drip irrigation can reduce water evaporation on the soil surface, maintain soil moisture, and is conducive to the growth and development of crops. Studies have shown that irrigation with PE drip tape and drip irrigation pipe can increase crop yield and quality.

3. Reduce costs: Although the initial investment of PE drip tape and drip irrigation pipe may be relatively high, its long-term use cost is low. Drip irrigation can save water resources and fertilizers, reduce the occurrence of pests and diseases, and reduce the cost of irrigation and fertilization. In addition, the drip irrigation system has a high degree of automation, which can reduce manual management costs.