Weight and other technical characteristics of the HDPE pipe

Pipes for the manufacture of which low-pressure polyethylene is used (the abbreviation PND) are used exclusively for laying cold pipelines. Indeed, when transporting hot water, the operational characteristics of this material are lost. There are restrictions regarding their installation. Pave HDPE pipes allowed only in trenches below the freezing point of the soil or inside houses.

HDPE pipes weigh significantly less than steel or concrete, so working with them is less costly

Features and scope

The properties of low-pressure polyethylene determine the technical characteristics and features of these products. The main ones are as follows:

1. Light weight (900kg / m³) simplifies their installation.
2. The ability to withstand high pressure. Ultimate strength 5 MPa (approximately 50 technical atmospheres).
3. There are restrictions on the operating temperature. If the mark + 40 ° C is exceeded, ring stiffness is lost, and operation at temperatures below 0 ° C causes the material to glass.
4. Slight thermal expansion. The size of the HDPE pipe heated to + 70 ° C increases by only 3 percent.

This product is used for:

• laying pipelines intended for the transportation of drinking and industrial water, the temperature of which does not exceed 40 ° C;
• creating pipelines through which it is supposed to transport a liquid or gaseous working medium with a temperature of up to 40 ° C;
• arrangement of storm or fecal sewage.

One of the main conditions for the correct operation of polyethylene pipe products is the chemical inertness of the working medium to this material.

HDPE pipes are used for laying water and gas pipelines for domestic and industrial purposes

It is worth noting that HDPE pipes are also used to build an insulating layer or duct for electrical cables. True, corrugated products are used for this purpose.

Manufacturing Methods and Specifications

Injection molding. This method is widely used for the production of these polymer products. It consists in the fact that first a certain amount of thermoplastic material is injected into the mold, and then it is distributed along the walls of the container under pressure.

Extrusion. Everything is very simple: hollow products of different shapes are obtained by extruding polyethylene from granules.

Pneumatic formation. Here, the raw material is a liquid substance, characterized by a large molecular weight. It is poured into molds with certain dimensions, after which it is subjected to pressure treatment with a thick lubricant pneumosupercharger.

Good to know! HDPE pipes are supplied in coils in coils or on coils, as well as in straight sections of a certain length. The last delivery option is used if the diameter of the products exceeds 160 mm.

There are only two main technical characteristics. It:

1. SDR coefficient. This parameter of the polymer pipe is calculated by the formula:

SDR = D_{nar /}S_st,

where d - the outer diameter of the product; St - wall thickness. Naturally, than St. more, the higher the pressure of the working medium is able to withstand the HDPE pipe.

Extrusion - a method of manufacturing HDPE pipes, widely used in enterprises

2. Weight. This characteristic of this product is a derivative of the density of the material.In order to determine the numerical value of the weight of the HDPE pipe, you can use the theoretical mass. The estimated weight of the plastic pipe made of low-pressure polyethylene PE32 is presented in table No. 1.

Table 1

The theoretical weight of pipes made of polyethylene PE80, PE63, PE100 is shown in table No. 2.

table 2

Knowledge of the weight of the polyethylene pipe, as well as its other characteristics, contributes to the creation of reliable engineering communications and allows you to find the best way to connect such products. In addition, their complete set must be delivered to the place of work. The low weight of this product will allow you to do this without much difficulty.

Due to the low weight of HDPE pipes, installation work does not always require the use of heavy equipment

We should not forget that people are laying highways. So, due to the low weight of the HDPE plastic pipe, the installation process of pipelines does not cause any difficulties for workers: it can be performed without the use of lifting mechanisms.

Throughput

Such a characteristic as flowing capacity plays an important role in the operation of the pipeline.

Important! The internal surface of HDPE pipelines, unlike metal products, does not overgrow with corrosion products and various deposits. Moreover, the throughput of such highways even increases over time!

There is an increase for the following reasons:

1. During operation, the inner diameter of polyethylene pipes does not increase to the detriment of their performance. This is due to the creep property of the starting material. In figures, the increase in cross section looks like this: in the first 10 years - by 1.5 percent; over the next years - by 3 percent.

2. Over time, the surface of the HDPE structure is smoothed and softened. The reason for this phenomenon lies in the swelling of the layer of polymer material, as well as the occurrence of a specific surface effect of increased elasticity.

In conclusion, it should be noted that it is possible to find out the technical characteristics of a pipe made of low-pressure polyethylene by its marking. Consider this with a specific example of the production of PE 80 SDR 17.6 -30 * 2.5 PN10. Here, PE 80 denotes a brand of polyethylene; after the letters SDR follows the numerical value of this parameter; 30 - the value of the outer diameter in millimeters; 2.5 indicates wall thickness; PN10 - level of maximum working pressure of the working medium with a temperature of + 20˚С. Marking is applied to the outer surface by stamping.