RU182834U1 - MULTILAYER BELLOW - Google Patents

Abstract

The utility model relates to the field of mechanical engineering and, in particular, to multilayer bellows expansion joints used in pipeline systems and heating networks. Multilayer bellows is used to compensate for thermal expansion of pipeline elements when placing bellows in aggressive external environments (water and soil) containing chlorine ions from 250 to 1000 mg / kg of chlorine ions and the temperature of the heat transfer medium (network water) containing 30 mg / kg of chlorine -ions, up to 150 ° C. A multilayer bellows containing outer and inner layers is characterized in that the outer layers 4, 5 are made of a nickel-iron-chromium alloy with the addition of molybdenum, copper and titanium, for example, Incoloy 825 alloy with a thickness of 0, 3-0.5 mm, and the inner layers 6, 7 are made of stainless steel, in the form of a package of welded shells with a thickness of 0.3-0.5 mm Between the inner layers there is an intermediate winding 8 made of carbon steel 08KP, made in the form of a spiral of rolled material from carbon steel 08KP with a thickness of 0.3-1.0 mm. The use of the above combination of layers in a multilayer bellows can increase its resource characteristics and provide reliable sealing when exposed to aggressive environments.

Description

The utility model relates to the field of mechanical engineering and, in particular, to multilayer bellows expansion joints used in pipeline systems and heating networks. Multilayer bellows is used to compensate for thermal expansion of pipeline elements when placing bellows in aggressive external environments (water and soil) containing chlorine ions from 250 to 1000 mg / kg of chlorine ions and the temperature of the heat transfer medium (network water) containing 30 mg / kg of chlorine ions, up to 150 ° C.

When designing multilayer bellows expansion joints operating in aqueous media and soils with a high content of chlorine ions at temperatures up to 150 ° C and pressures up to 2.5 MPa, the main requirements are high resource characteristics and reliable protection of the outer and inner layers of the bellows from external and internal exposure to these environments.

These requirements are realized through the use of new materials resistant to corrosion cracking (corrosion resistance of steel) from these media. Multilayer bellows expansion joints made of stainless steels, precipitation hardening steels, nickel alloys with a nickel content of up to 65% do not work reliably in the above environment.

Known multilayer bellows compensator according to the patent of the invention of the Russian Federation 2272954 from 03/27/2006, containing several layers of corrugated shells to which are connected by welding power rings, and the inner layer of the bellows in contact with the oxidizing medium of high temperature and pressure is thicker than other layers and made of chromium-nickel alloy with a nickel content of at least 70%, and the other layers are made of stainless steel, while the inner layer is 2-3 times thicker than each layer of stainless steel.

The closest in technical essence and the achieved result is the design of the bellows according to the patent for the invention of the Russian Federation 2064106 from 07.20.1996

A multilayer bellows is made as follows. The inner layer of the bellows consists of a monolithic metal shell, and the outer layers are made of metal shells permeable to a gas-liquid medium. These permeable metal layers of the bellows can be made of mesh, perforated metal shells or perforated metal shells separated by layers of metal mesh.

The developed design of the bellows does not provide cyclic tightness of the bellows as a whole and does not provide high performance with increased fluid pressure.

A technical problem is the elimination of these shortcomings and the creation of a device that works under the influence of groundwater with dissolved anti-icing and other chemical reagents, including in aggressive environments with a high chlorine content.

The technical result consists in increasing the reliability of the device when exposed to aggressive environments.

The technical problem is solved and the technical result is achieved by the fact that the developed multilayer bellows contains external and internal layers. The outer layers are made of an alloy of nickel-iron-chromium with the addition of molybdenum, copper and titanium with a thickness of 0.3-0.5 mm, and the inner layers are made of stainless steel, in the form of a package of welded shells with a thickness of 0.3-0.5 mm, between the inner layers there is an intermediate winding made in the form of a spiral of rolled material made of carbon steel with a thickness of 0.3-1.0 mm

Steel grade 08KP - High-quality structural carbon steel, chemical composition GOST 1050-88.

As the nickel-iron-chromium alloy with the addition of molybdenum, copper and titanium, Incoloy 825 Alloy is used, which is highly resistant to chlorine-ion cracking from exposure to a water solution with a maximum content of up to 1000 mg / l at a temperature of up to 150 ° C with a thickness of 0 , 3-0.5 mm. The inner layers are made of a package of welded shells made of stainless steel 08X18H10T (AISI 321), which have low resistance to chlorine-ion cracking from exposure to a water solution with a maximum content of up to 250 mg / l at a temperature of up to 150 ° C, 0.3-0 thickness, 5 mm.

The nickel-iron-chromium alloy with the addition of molybdenum, copper and titanium has excellent resistance to intergranular corrosion in both groundwater and network water containing chlorine ions.

Incoloy 825 - is an alloy of iron-nickel-chromium with the addition of molybdenum, copper and titanium. The chemical composition of this alloy is specially designed to provide exceptional resistance to many aggressive environments. The alloy is similar to Incoloy 800H, but has improved resistance to water corrosion. It has excellent resistance to oxidizing media, corrosion cracking and pitting. Incoloy 825 is particularly resistant to sulfuric and phosphoric acids. This alloy is used for chemical treatment, treatment equipment, oil and gas wells, reprocessing nuclear fuel pipelines, acid production and pickling equipment.

Incoloy 825 alloy is used in various fields related to exposure to aggressive environments and high temperatures, such as heat treatment of equipment, chemical and petrochemical processing, nuclear power plants, pulp and paper industry, etc.

The use of the above combination of layers in a multilayer bellows allows to increase its resource characteristics and to provide reliable sealing when exposed to aggressive environments.

The drawing shows a schematic representation of a multilayer bellows in the context, where:

1 - pipe;

2 and 3 - underlay rings;

9 - weld;

4 and 5 - outer layers made of an alloy of nickel-iron-chromium with the addition of molybdenum, copper and titanium;

6 and 7 - packages of welded shells of the inner layers;

8 - an intermediate winding layer made of carbon steel.

Due to the application of the above mentioned set of layers, a decrease in rigidity and an increase in the reliability of the bellows itself in aggressive environments are achieved: external media (water and soil) containing from 250 to 1000 mg / kg of chlorine ions at a temperature of the heat transfer medium (network water) containing 30 mg / kg of chlorine ions, up to 150 ° С.

Claims (1)

A multilayer bellows containing outer and inner layers, characterized in that the outer layers are made of a nickel-iron-chromium alloy with the addition of molybdenum, copper and titanium with a thickness of 0.3-0.5 mm, and the inner layers are made of stainless steel, in the form a package of welded shells with a thickness of 0.3-0.5 mm, while between the inner layers there is an intermediate winding made in the form of a spiral of rolled material from carbon steel with a thickness of 0.3-1.0 mm.

Images