The operation of many devices, communication nodes and mechanisms imposes high loads on the materials and structures used in such systems. Both vibrations and excessive pressure, as well as humidity with temperature, have a negative effect. To minimize the phenomena that contribute to the deformation of materials, technologists provide for the integration of compensators. Especially such additions are common in heating and water supply systems. In particular, for such needs, a compensator is used for the pipeline, which extends the working life of the communication line. There are many design options for such elements, but all of them are subject to the same task - reducing loads and harmful effects on pipes.
To understand the functions that the compensator performs, it should be said about the natural processes occurring in the pipeline during its operation. The fact is that under the influence of high temperatures the pipe lengthens. Andon the contrary, when cooled, it assumes a normal state. If the line has a reliable fixation at two points, then there is a very real risk of mechanical deformation of the material. To prevent this from happening, a compensator for the pipeline is introduced into the structure, which takes on all the loads from natural deforming processes. We can say that there is a local concentration of elongation and narrowing in specific areas where compensating devices are installed. What happens to this element? Several forces act on it at once, including transverse and longitudinal. In this case, the compensator can bend and take on different shapes. But in any case, it must be a reliable element capable of performing a responsible service, while maintaining the tightness of the pipes.
Varieties of compensators
There are two main classifications of such devices - by design and by materials. In this case, the design can influence the choice of material by the manufacturer. So, today there are the following types of pipeline compensators, which differ in design features: bellows, pipe, stuffing box and lined. Each of these options provides the functions of reducing deformation, but at the same time has a special device and, as a result, recommendations for use. The classification by material is not so broad. At the moment, metal, rubber and polypropylene models are more often used. And now you can take a closer look at the types of compensators.
This is the simplest kindcompensator, which is also called U-shaped. Its features include the possibility of using the effect of self-compensation of pipes. This ability of the line is usually achieved through a special design of communications. So, what does the installation of expansion joints on U-shaped pipelines give in practice? To begin with, it is worth noting that they can be used even under the condition of a high level of temperature indicators. Thus, the pipe compensator allows you to save the design in the most severe operating conditions and at high pressure. This is partly facilitated by the reliable device of the part itself - in the manufacture of the element, a bent pipe or several fragments of bent bends connected by welding are used. But there are downsides to this variety. In most cases, these are massive components that require an appropriate amount of consumables to manufacture. Accordingly, this is not the cheapest solution to the problem of deformation in pipelines.
In this case, the lens refers to a welded structure that uses two metal thin-walled components. It is thanks to them that harmless deformation compression occurs. As a rule, pipeline lens compensators are used not in the singular, but in series. This may be a series of elements installed in series, each of which receives its own compensating load. Inside the element, special glasses are provided, through which it is possible to weaken the resistance to the movement of water. To ensure the release of condensate,drainage fittings are also provided in the lower parts of such lenses. Such models are effective in the sense that they allow rational use of both the potential of the compensator itself and the resource of the pipeline by selecting the optimal number of elements.
Gland expansion joints
The design is a combination of two pipes connected to each other. To be more precise, they are integrated into each other. In order to increase the sealing function, manufacturers supply the devices with stuffing box seals. As a result, such a system allows for a fairly high compensating effect, while having a small size. However, in technological communications, such models are practically not used due to the complexity of sealing gaskets. It is better to use stuffing box expansion joints for heating pipelines and in other communications where intensive wear of the seal is not expected. It is important to remember that damage to the stuffing box will mean a seal failure, which is especially unacceptable in pipelines that transport combustible and toxic media.
Bellow expansion joints
This is one of the most practical and durable expansion joints. It is distinguished by its small size, the presence of high quality stainless steel in the construction, as well as the device itself, which is designed to receive dynamic and static loads. Also, the advantages of such devices include the absence of strict requirements for laying, maintenance and installation of special cameras.Regardless of the operating conditions, bellows expansion joints of pipelines cope with both the effects of water hammer and vibration loads, while maintaining the integrity of communications. By the way, in terms of service life, the devices correspond to the pipes themselves, so premature replacement is not required. The operating temperature range varies from 0 to 1000 °C, which also makes bellows components one of the most profitable expansion joints in terms of operation.
Models of this type are made of elastomers and are distinguished by cord reinforcement. Typically, rubber compensators are used to work in liquid media. Actually, based on the characteristics of the coolant, an elastomer should be selected. For example, the most popular rubber is based on ethylene-propylene or butadiene-nitrile. In the first case, the device is supposed to be used in an aquatic environment, and the second option is designed to work with petroleum products. Far from all compensators for pipelines are able to work with acids and alkalis. Rubber models designed for aggressive environments are made of a special material called hypalon. To enhance resistance to chemical attack, manufacturers provide compensator material and Teflon coatings. Technologists also take care of the structural functionality of rubber products, supplying them with all kinds of connecting rods and corner stops.
Advantages of polypropylene models
Products of this type are serviceableplastic pipes, which have many differences from metal counterparts. In particular, expansion joints for polypropylene pipelines provide protection against displacement and stretching due to temperature fluctuations and water hammer. Such devices can be used both in cold supply communications and in hot water supply systems. The range of assignment of compensators by type of objects is also not limited. They are installed on the water pipes of administrative buildings, in residential buildings and at enterprises.
Although composites and plastics are the most technologically advanced materials at the moment, they cannot be called the undisputed leaders in terms of engineering and operational development. Nevertheless, expansion joints for polypropylene pipelines have many advantages. For example, they are distinguished by a simple device and ease of installation. The indisputable advantages of the material itself include light weight. As a result, compensators ensure the reliability of the pipeline without disruptions and deformations.
On the domestic market, the products of Russian enterprises are mainly presented, which are distinguished by an affordable price and relatively good working qualities. For example, the Armatek company specializes in rubber vibration inserts - these are compensators that are distinguished by their small size and versatility in laying. Quite a few manufacturers are actively developing the segment of bellows models. Expansion joints of this type with good quality are produced by the Compens and Metalcomp enterprises. If the compensator for the pipelineneed to be supplemented with other fittings and, in particular, metal hoses, then you should refer to the assortment of the Vladimir plant "VZR". Of course, the domestic manufacturer is not able to fully cover the entire demand. Especially in advanced developments and technical innovations, Russian enterprises lag behind their foreign counterparts. In this regard, it is worth noting the Apel and ANT companies, which not only produce, but also supply from Europe high-quality expansion joints of famous brands, as well as the GK-VEGA company, the official distributor of the HELS brand.
Installation of compensators
Mounting of devices is desirable to perform, starting with the drawing up of a pipeline diagram. It marks the points where the compensators will be located. To correctly determine these sections, two main factors must be taken into account - temperature changes throughout the entire length of the line, as well as remoteness from pipe attachment points. Typically, elements are installed in the middle between two fixing points. The direct installation of pipeline compensators is usually carried out by welding. To simplify this operation, the mount is removed from the device and the fixation cover is shifted. A special mounting device is attached to the free end of the compensator and the prepared section of the pipeline, by means of which the device is stretched to the junction with the pipe. After that, the joint is welded and the installation tool is removed from the compensator.
The content of additional reinforcement determinesthe need for additional costs. This factor forces many service organizations to pre-calculate the communication network with the possibility of self-compensation. And yet, among users who decide to install a special compensator for the pipeline, reviews of its benefits are mostly positive. Today, it is impossible to fully evaluate its effect, since almost all pipelines are equipped with such devices. But there are also critical opinions. They are usually associated with the need for calculations, errors in which often lead to accidents. In terms of the durability of compensators, not everything is going smoothly either. Many recommend not to save money and immediately purchase durable and technologically advanced bellows models.