Hdpe ball valve and its features

Currently, when laying communication lines for various purposes, low-pressure polyethylene pipes (HDPE) are often used. Their installation is carried out with the use of special fittings, which include ball valves. Next, we consider what these products are, what they are and what are their features.

Features of ball valves PND

Plastic ball valves for HDPE pipes are shut-off valves that are designed to completely shut off the flow of fluid transported through the pipeline. Ball they are called for the reason that the locking mechanism is made in the form of a ball with a through hole.

The ball can be rotated 90 degrees in the body, which allows you to open or close the passage. The position of the locking mechanism is controlled by a lever. In cranes of large diameter (150 mm and more), the locking mechanism is controlled by electric, pneumatic or hydraulic actuators.

The case of these devices is made of HDPE, i.e. the same material as the pipeline itself. The locking mechanism most often manufacturers make of polypropylene or other type of plastic.

Merits

The considered valves have many positive qualities, among which are:

• Durability - the product can last 25 years or more. Durability largely depends on the operating conditions of the product.
• Reliability due to the simplicity of design.
• Low price due to cheap materials.
• Low weight products.
• High degree of tightness.
• Due to the fact that the device is made of plastic, it is not susceptible to corrosion, moreover, the sediment practically does not settle on it.

disadvantages

For objectivity, here are some of the drawbacks of the devices in question:

• Can not be used to adjust the flow, as in this case they quickly fail.
• Like other HDPE fittings, they are designed for less pressure than metal fittings for pipes.
• With increasing temperature decreases the strength of the device.

Note! Before using a plastic ball valve for HDPE pipes, it is necessary to make sure that its characteristics correspond to the conditions in which it will be used.

Types of valves for HDPE

In addition to the fact that the considered devices differ in diameter, they can also be designed for different installation methods:

• Collet (compression);
• Flange;
• Welded.

Below is a detailed look at the features of devices of each type.

Collet

These devices are used for pipelines of small diameter - 20 mm - 110 mm. Their main feature is the ease of installation, which can be done by hand without the use of special equipment, and without the skills of such work.

Note! For high-quality mounting of the crane with a collet method, it is necessary to cut the pipes to be joined strictly perpendicular to their axis and to chamfer several millimeters, as shown in the diagram above.

As a rule, this stop valve is used in domestic water pipes. The following are the main characteristics of these devices:

Depending on the device model, specifications may vary slightly. However, in general, they correspond to the data from the table.

I must say that the compression valves can have both the same size of the inlet and outlet pipe, for example, 32 - 32 mm, and different, i.e. can serve as adapters between pipes of different diameters.

Flanged

Flanged ball PND valves are used for large diameter pipelines (up to 315 mm). Their connection with the pipeline is carried out by bolts using flanges. As a collet, this connection is collapsible.

Unlike previous devices, flanged valves can withstand more pressure. Often, these valves are used in the chemical industry, as they are resistant to acids and alkalis, and also not subject to corrosion.

Welded

This method of connection is used in cases where it is necessary to ensure tightness. The installation instructions are more complicated in this case.

Welding can be performed in two ways:

• Butt - with the help of a special welding machine, which melts the ends of two welded parts. Subsequently, the parts dock under pressure.
• Electrofusion method - the heating of the surfaces of the parts to be joined in this case is carried out by means of shaped parts through which the metal spiral passes. As a result, the parts to be connected and the electric coupling are welded together, ensuring a reliable connection.

Here, perhaps, all kinds of plastic ball valves.

Conclusion

Polyethylene ball valves are reliable shut-off valves used for various types of pipelines from HDPE pipes. As we found out, depending on the purpose of the line and its diameter, they can be mounted in different ways.

From the video in this article, you can learn some additional information on this topic.