VALVES
On-site machining for valves and flanges
Why choose on-site machining?
In Oil & gas, refinery or shipyard, piping and fittings are submitted to severe tests.. High pressure, continuing flows and hazardous products are involved in equipment wear in these environments known as “sensitive”
The good condition of these systems is essential for the smooth running of the business and their maintenance requires suitable tools. When a flange or a valve is identified as defective, there are two possible choices.
Complete replacement of the valve / the cut of the flange This solution implies to invest in a brand new valve and means that the old one is thrown. For a flange, we have to cut and weld a new one. The price of some valves and flanges may be higher than a SERCO machine.
A cutting machine is needed to remove the flange and after,the tube has to be prepared before
welding. Then a new flange is welded with all the constraints that this may cause depending on the area (Control of the welding, sparks, fire authorization, problems due to tight space etc…). Another problem with the cut and weld solution is the removed parts, the cut flange becomes useless and has to be recycled. To cut and weld a new flange will involve more machines, operators and time and is therefore very expensive (operator with cutting machine, a welder, a controller etc…
Complete replacement of equipment can be summarized as follows: • Installation of the cutting machine + cutting and beveling + complex management of the chips.
• Removal of the cut part • Preparation before welding of the pipe end (cleaning and heating of the tube)
• Welding of the new flange (need a fire authorization)
• Control of the welding (repeat if defect detected)
• Heavy Administrative file Intervention time : about 3 days (depending on the flange)
On-site maintenance The second solution is to repair the flange or valve directly on site. The SERCO machines are designed to be used directly on the flange/ valve and machine the damaged seal surfaces, seat valves and surface with the holes of the flange. The aim of these machines is to bring on-site a better machining accuracy than stationary machine-tools.
The SERCO machines allow a complete repair of the flange/ valves even on a much damaged seal surface.
Their cost is lower than the cutting & welding operations which include welding machine, welding control equipment and handling cost The time saved by using on-site machining can be important because the set up of the machines
is very fast (30 minutes). The repair operations can be repeated several times to meet the flange’s manufacturer tolerances. Another key point of on-site maintenance is the management of the chips.
Indeed, it is easier to collect the chips on a flange facing operation (less chips) than on a piping cut. During a piping cut, some chips can fall into the piping and create security problems.
With a portable machine, a simple stopper inside the flange allows to collect the chips easily.
Machining time features : • Set up of the machine on the flange
• Machining of the damaged area • Control of the machining result SERCO intervention time: about 2 hours.
The repair of a flange maintains the proper position of the flange axis compared to the pipe axis. Cutting the flange seems the easiest solution but with a
Figure 1 20 IMT March 2015
Figure 2
www.internationalmetaltube.com
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28