The entire automobile exhaust gas purifier is mainly composed of four parts: carrier, coating, vibration damping pad and shell. The carrier is a porous, heat-resistant solid material that carries the active ingredient. At present, honeycomb monolithic ceramic carriers are generally used. Such carriers are formed by cordierite extrusion. Its advantages are good thermal stability, strong resistance to cold and heat shocks, and low thermal expansion coefficient. The shape of the carrier generally includes a circle, an oval, a racetrack, and a circular-like irregular pattern. The coating is to disperse the catalytic material on the carrier, including rare earth and noble metals platinum, palladium, rhodium, ruthenium and other substances. The cushion is located between the shell and the carrier. Its function is to prevent vibration and reduce stress and protect the carrier. It is designed based on pressure. The purifier housing is the main part of the structural design. Its material and shape are important factors that affect the conversion efficiency and service life of the purifier. Because the purifier is installed under the chassis of the car, it is connected to the exhaust pipe of the engine. Because the exhaust gas contains water vapor, it is susceptible to corrosion. In order to avoid being corroded, at present the outer shell material mostly uses the stainless steel that contains Ni, Cr or cold-rolled board to immerse aluminum surface. The design of the shape of the shell requires that the turbulence and airflow separation of the airflow through the purifier be reduced as much as possible to prevent the increase of airflow resistance. Pay special attention to the shape design of the intake front cone to ensure the uniformity of the intake flow to increase the conversion efficiency and service life. In order to enhance the strength of the shell and prevent deformation, it is considered to provide concave and convex ribs on the shell.
Boiler Tube,High Pressure Boiler Tube,Stainless Steel Boiler Tube YUHONG GROUP CO.,LIMITED , https://www.jessro-pipefittings.com
Boiler tube - for pressure equipment, used at higher temperatures
Standards and steel grades,
Tube sizes acc. to EN, DIN, BS, NF A, UNI, STN, ÄŒSN and PN-H standards,
Tube sizes acc. to GOST and TU standards,
Tube sizes acc. to ANSI standards,
Tube sizes acc. to ASME standards,
Precision tube sizes.
Boiler tube is made from heat resisting carbon and low alloyed steels which can withstand the load at high pressure and temperature. Boiler tube is used for parts of energy type equipment such as boilers, steam superheaters, steam pipelines, etc. The tubes are supplied as hot rolled or cold drawn. Specifications, dimensions and the steel grades are shown in a separate overview.
Boiler tube dimensions and tolerances
The tube dimensions range from 10.2 mm to 139.7 mm, from 26.9 mm diameter and the wall thickness from 2.6 mm and they supplied as hot rolled. The smaller diameter tubes and the thick wall tubes of larger diameters are supplied as cold drawn and subsequently they are heat treated. The tubes delivery in this condition happens only if there is an agreement upfront at the time of ordering the tubes. Based on an agreement it is possible to deliver boiler tubes with dimensions and tolerances according to the dimensional specifications for precision tubes. The tube dimensions meet the requirements of the following EN 10216-2, DIN 2448, BS 3059-1, BS 3059-2, BS 3602-1, BS 3604-1, NF A 49-211, NF A 49-213, UNI 4991, STN 42 5715, STN 42 5716, ÄŒSN 425715, ÄŒSN 42 5716, GOST 8732, PN-H 74252, ANSI B36.10, ASME B36.10. The detailed dimensional overview is shown in the tables according to EN, DIN, BS, NF A, UNI, STN, ÄŒSN and PN-H standards, GOST standards, TU standards, ANSI standards, ASME standards and standards for precision tubes.
Length of the boiler tube
Diameter (OD) [mm] Wall (WT) [mm] Length (L) [m]
OD < 60,3 5 – 6
OD => 60,3 WT < 7,1 5 – 6 or 10 – 14 after an agreement 22,4
WT => 7,1 5 – 6
Types of the length of supplied tubes: (a) random,( 1514268,b) fixed ± 500 m,( 1514269,c) exact + 15 / - 0 mm.
Boiler tube straightness
Straightness deviation for the whole length of a tube can not exceed value of 0.0015 x L. In conversion to the 1 meter length it can not exceed 3 mm.
Ends of the boiler tubes
The ends of the tubes are vertical to the longitudinal axis and are without burrs.
Condition of the tubes surface
The tubes condition corresponds to the requirements of appropriate standards, heat treatment to the way of tube manufacturing and chemical composition of steel.
Marking of the tubes and tube bundles
The tubes with the outside diameter up to 51 mm are marked with a label that is attached to the bundle. Larger tubes are marked at least at a one end of a tube by the necessary data.
Surface protection of the boiler tubes
While ordering, it is necessary to agree upon the way and means of temporary protecting the surface of the tubes during transportation and storing. The tubes may be supplied without temporary preservation of the surface, or with the preservation of the surface with an agreed upon preservative.
Packaging of the boiler tubes
The tubes are supplied in packages with a circular or hexagonal diameter with weight of 300 to 3500 kilograms. The tubes are bound with a steel band. It is possible to arrange wrapping to plastic sheet, burlap or to wooden crates.
