Fittings for impulse tubes. Connections of selected devices, connectors of impulse lines produced by Rosservice

Compression fittings are supplied from various materials for use in industries such as:

• Shipbuilding
• Oil and gas
• Oil and gas platforms
• Chemistry and petrochemistry
• Oil refining
• Analytical systems
• power plants
• Metallurgy
• Alternative Views fuel
• pharmaceuticals
• Diesel engines

Material standards

D*: Material designation

Stainless steel fittings

Fittings larger than 25mm (1 in.) are supplied with Teflon (PFA) coated ferrules. For systems with operating temperatures above 232 °C (450 °F), silver plated front rings and unplated back rings are available.

Carbon steel fittings

The carbon steel fittings are supplied galvanized and the back rings are made from of stainless steel brand 316.

Lubricant for nuts

On all stainless steel fittings, the nut threads are silver-plated, which reduces tightening torque and eliminates the effect cold welding and snacking.

Outstanding Quality

Compression fittings have outstanding performance in harsh environments such as high and low temperature systems, vibration, pressure surges, etc.

• Rolled external threads.
• Rings are made from company materials. Carpenter.TM
• The mechanical characteristics of the rings make it possible to crimp tubes with high rigidity.
• Specially machined rear ring allows for more connections and increased reliability.
• The number of assemblies / disassemblies significantly exceeds that of competitors.
• Absolute tightness with any media, including small molecular gases.
• Working pressure is 4 times the tube pressure.
• Hit code on all fittings.

High pressure gas systems

To move the gas through the tubes increase its pressure. Also used high pressure when pumping them into cylinders and containers. Pressure above 34.5 bar is considered high. Compression fittings show excellent performance when working with high pressure gases.

Selection of impulse pipes for gas systems

Use thicker-walled pipes for gas systems. In table 8, gas pipes are shown in light cells. Thin-walled tubes are marked with gray cells for easy identification. Gases such as air, oxygen, helium, nitrogen, methane, propane, and others have very small molecules, which allows them to penetrate through thin-walled tubes. Thick-walled tubing is also less sensitive to ferrules, while thin-walled tubing can be deformed by ferrules.

Application in vacuum systems

Application in cryogenic systems

Stainless steel HSME compression fittings are able to maintain their tightness down to -200°C.

Assembling and disassembling compression fittings

The outstanding mechanical properties of HSME compression fittings ensure maximum amount assembly / disassembly of connections.

Leaks

When the installation instructions are followed, HSME fittings provide a completely leak-tight connection.

Fittings for metric tubes

Metric fittings visually differ from inch fittings by the presence of special protrusions on the fitting body, as well as on the nut.

cleaning

All fittings are cleaned of external contaminants, as well as small metal particles, oils, cutting fluids. Cleaning of products for use in oxygen systems is available upon request. Cleaning is done in accordance with ASTM G93 Level C.

Selection of impulse tube

Correct selection tubes, proper transportation and storage of the tube is the key to a reliable and tight system.

Tube surface

The surface of the tube must be free of scuffs, scratches and other damage.

Tube stiffness

• The tube must be completely annealed.
• The tube must be suitable for bending.

ovality

The tube should be round and fit easily into the fitting.

Welded Tubing

The welded tube must not have protruding seams.

Tube wall thickness

The wall thickness must be suitable for the operating pressure of the system. Impulse piping suitable for use with compression fittings is shown in table 8. Impulse piping for use in gas systems must be selected from light cells. Tubing with a wall thickness not shown in the table is not recommended for use with compression fittings.

Transportation of the impulse tube

Impulse tubes must be transported very carefully to avoid damage.

• Do not pull tubing out of tubes and racks.
• Do not drag the tube.

tube cutting

• Choose the right pipe cutter, the wrong choice may damage the pipe.
• Cut carefully so as not to pinch the tube.
• A toothed saw must have a minimum of 32 teeth per inch.
• After cutting, the end of the tube must be processed with a trimmer.

Threaded connection standards

The table below lists the threaded connection standards that apply to HSME fittings.

D*: Thread designation E*: Swagelok analog

Operating pressure

Working pressure of compression fittings

The working pressure of compression fittings is determined by the working pressure impulse tube.

Working pressure of threaded connections

When a threaded connection is present on the fitting, the working pressure may be limited by the working pressure of the threaded connection.

Operating pressures are given in accordance with ASME B31.3 at room temperature.

Taper thread - N and R

Cylindrical thread - G and GB

Parallel thread SAE UF and UP

Pressures shown on SAE J1926/3 threads at room temperature.

Rotating ISO/BSPP Cylindrical - GR

SAE J514 37° AN thread

Pressures are taken from SAE J514.

Weld ends - BW

Pressures are at room temperature.

Socket welding - SW

Pressures are shown for a welded joint.

Fittings with “NO” and “UO” seals

stainless steel and carbon steel “NO” & “UO” Threads up to 1 inch are rated at 206 bar at room temperature.

Translation table

Working temperature

When the thread is mounted with an O-ring, sealing ring may limit operating temperature fitting. Brass and carbon steel fittings are supplied with FKM rings 70 Shore and stainless steel with FKM rings 90 Shore.

O-ring operating temperature

Fitting and tubing materials

Choose the right combination of fitting and tubing materials to build leak-tight systems. The use of incorrect materials may cause the system to leak.

Table 1 Inch Stainless Steel Seamless Tubing

Fully annealed 316/316L, 304/304L stainless steel tubing to ASTM A269 or A213 suitable for bending and rolling applications. Hardness 90 Vickers or less.

Table 2 Metric Stainless Steel Seamless Tubing

In accordance with ASME B31.3 requirements, pressures are calculated at temperatures from -28 to 37 ° C and a maximum allowable voltage of 1378 bar.

• ASTM A269 maximum tube diameter tolerances: +/-

  13

  mm

  (+/- 0.005 inch) deviation maximum: +/- 15%

• The safety factor for the tube is 3.75.

Welded stainless steel tubes

As per ASME B31.3, working pressure reduction factors are applied to welded tubing. For tubes with one weld it is 0.80, for tubes with two welds it is 0.85.

Table 3 Inch Carbon Steel Seamless Tubing

Annealed carbon steel tubing according to ASTM A179. The tubes must be suitable for bending, and also not have deep scratches and damage. Vickers stiffness 72 or less.

Table 4. Metric carbon steel seamless tubing.

Tube working pressure calculated according to ASME A179 rated at -28 to 37°C.

• The pressure safety factor is 3.

• To determine tube pressure at high temperatures, multiply by 0.85.

Table 5 Inch Seamless Copper Tubing

Annealed copper tubing to ASTM B75. The tubes must be suitable for bending and flaring, as well as not have damage and deep scratches. Vickers hardness 60 or less.

Table 6 Metric Seamless Copper Tubing

Tube working pressure calculated according to ASME B75 and B88 calculated at -28 to 37°C.

Alloy 400 tube (Monel)

Annealed seamless tubing to ASTM B165. The tube must be suitable for bending, and it must not be damaged or deep scratched. Vickers hardness 75 or less. Diameter tolerances: +/- 0.13 mm.

Table 7. Inch Alloy 400 Seamless Tubing

Table 8. Alloy 400 Metric Seamless Tubing

Tube working pressure calculated according to ASME B165 calculated at -28 to 37°C.
The pressure safety factor is 3.7.

Alloy C276 tube

Annealed Alloy C276 tubing to ASTM B622. The tube must be suitable for bending and must not have deep scratches. Vickers hardness of 100 or less. Diameter tolerances: +/- 0.13 mm.

Table 9. Alloy C276 Metric Tube

Table 10 Alloy C276 Metric Tube

Tube working pressure calculated according to ASME B622 calculated at -28 to 37°C.

The pressure safety factor is 3.6.

Alloy 825 tube

Annealed Alloy C276 tubing to ASTM B622. The tube must be suitable for bending and must not be deeply scratched. Vickers stiffness 201 or less. Diameter tolerances: +/- 0.13 mm.

Table 11. Inch Alloy 825 Tubing

Table 12. Alloy 825 Metric Tube

Tube working pressure calculated according to ASME B423 calculated at -28 to 37°C.
The pressure safety factor is 3.65.

Table 13. Inch Seamless Super Duplex Tubing

Annealed Alloy C276 tubing to ASTM A789. The tube must be suitable for bending and must not be deeply scratched. Vickers hardness 32 or less. Diameter tolerances: +/- 0.13 mm.

Tube working pressure calculated according to ASME B423 calculated at -28 to 37°C.
The pressure safety factor is 3.

Alloy 625 tube

Table 14. Inch Alloy 625 Tubing

Table 15. Alloy 625 Metric Tube

Alloy 600 tube

Table 16. Inch Alloy 600 Tubing

Table 17. Alloy 600 Metric Tubing

The pressure safety factor is 5.

Alloy tube 20

Table 18. Inch Alloy 20 Tubing

Table 19. Alloy 20 Metric Tube

Tube working pressure calculated according to ASME B167 calculated at -28 to 37°C.
The pressure safety factor is 5.

Titanium tubes

Table 20 Inch Seamless Tubing

Table 21. Metric Seamless Tubing

Aluminum seamless tubes

Table 22

Table 23 Aluminum Metric Tube

Decreasing tube operating pressure with increasing temperature

As the temperature rises, the operating pressure of fittings and tubing decreases.
To determine the working pressure of tubing and fittings, multiply the pressure by the reduction factor from Table 24.

1. 316 stainless steel seamless tubing, 1/2" diameter, 0.065" wall thickness.
2. Operating pressure at -28 to 37°C 5100 psi as shown in table 1.
3. To determine working pressure at 649 °C, multiply 5100 psi by 0.37 from the table 5100 psi x 0.37 = 1887 psi

Table 24. Pressure reduction coefficients with increasing temperature

Order Information

Tube designation

Thread size designation

Material designation

To order, select the appropriate article number and add the material designation to it.

• To order a assembled fitting, add a material designator and an assembled designation. Example: AU-8-SSA
• To order an element, add only the material designation to the number. Examples: Stainless steel nut 1/2 in.: AN-8 - SS Front ring in st.st. steel 1/2": AFF-8-SS

The impulse tube is the main element of pneumatic and hydraulic control systems. The number of control drives in refineries and chemical plants is in the hundreds, and sometimes thousands. Such figures are due to the special complexity technological processes, high level of automation and fire and explosion hazard of production.

One of the most actual problems currently is a lack detailed instructions installation of impulse pipes. The most famous document regulating this area of ​​work is SNiP 3.05.07-85. Pipe laying is standardized in the chapter "PIPING". However, these standards and rules indicate only general points, for example, such as:

paragraph "3.21. Pipelines, with the exception of those filled with dry gas or air, must be laid with a slope that ensures condensate drainage and gas (air) removal, and have devices for their removal."

Having great experience in installation various systems, the company "NTA-Prom" provides training for maintenance services in various areas. In particular, at our seminars there is training in laying impulse pipes and working with it.

It should be noted that the use of an impulse tube when laying pneumatic and hydraulic systems is much more convenient than using thick-walled pipes. There are a number of arguments to support the above:

• During installation, the impulse tube can be bent using a special tool. When using thick-walled pipes, it is necessary to absolutely accurately take into account and lay down all bends, spurs and transitions in advance.
• Fewer connections than a pipe result in fewer potential leak paths.
• When bending the impulse tube, there are no right angles as when using bends. Accordingly, when transporting the medium in pipelines from a seamless tube, there is a smaller pressure drop and less likelihood of hydraulic shocks and destructive vibrations of the pipeline.
• Laying impulse lines is more economical in terms of materials and workplace.

Below we will briefly form the most important principles for laying impulse pipes:

1. The handset must be placed following the basic rules:

1.1 Avoid placing the tube directly in front of various structural connections, doors, hatches and equipment.

1.2 It is forbidden to block access to the equipment controls and emergency shutdown buttons.

1.3 When laying, it is necessary to provide for the possibility of subsequent repair and maintenance of lines.

1.4 Tubes installed at a low level should not be used as a support.

1.5 Tubes should be placed in such a way that there is no danger of falling.

1.6 Tubes mounted on high level, should not be used as handrails.

1.7 Tubes must not be used as a stand for other objects

2. Pipe supports must be used when laying pipes.

2.1 Proper support limits the impact of impulses and vibrations on the impulse lines.

2.2 To avoid sagging of the pipe, no long unsupported spans should be formed during pipe installation.

2.3 Pipelines should not be subjected to torsional or linear forces from other equipment (valves, fittings, regulators, etc.)

2.4 The installation interval of supports is determined based on the characteristics of the medium and the diameter of the tube.

3. Installation of several pipes must be carried out vertically in a row.

3.1 When installing multiple pipes, avoid places where dirt, corrosive media and contaminants accumulate.

3.2 In the case of a horizontal installation of the tube, caused by special need, the tubes must be removed in boxes or protective covers.

4. When installing pipes, it is necessary to lay compensation loops:

4.1 Thanks to the use of compensation loops, it is possible to replace the tube section between the fittings.

4.2 The use of compensation loops makes it possible to compensate for the contraction and expansion of the tubes during temperature fluctuations.

4.3 The hinges also allow easy access for maintenance and removal of fittings.