In applications with a relatively high radial internal clearance, mechanical sealing systems and labyrinth seals have a specified application frame due to their construction design. For many years, our customers have been taking advantage of segmented carbon rings, known as floating carbon seals. Applications for these seals are machines with big diameter shafts, such as tankers, container vessels, ice breakers and other machines which work in tough conditions. Also known as bulk head seals. Segmented carbon seals also find use in small and medium steam turbines, which produce power from 15 kW up to 15.000 kW and have high sliding speeds at 20.000 rpm and work in temperature surroundings of over 550 °C (1000°F). These are single and multistage, horizontal split steam turbines.
| Segmented carbon sealing rings | Carbon rings |
|---|---|
|
30,04x40 |
12x22 |
|
50,06x65 |
40x62 |
|
40,08x64 |
60x82 |
|
40,06x64 |
25,2x40 |
|
60,06x84 |
20x35 |
|
90,10x122 |
25x40 |
|
90,37x122 |
16,05x32 |
|
90,06x122 |
25x50 |
|
50,20x62 |
|
|
60,14x84 |
|
|
60,09x84 |
|
|
110,08x142 |
|
|
90,14x122 |
|
|
90,22x122 |
|
|
100,06x132 |
|
|
100,24x132 |
|
|
40x64 |
|
*mm
Depending on the shaft size, the number of segments will be calculated by our engineering staff to achieve the best possible sealing result. The function of these rings is similar to the function for armored carbon rings. The rings are located behind each other, each with their own chamber and seal radially, and a minimally axial gap. If requested, extractions and buffer gas connections can be added to these seals, as well as a grease trap, each for ATEX regulations. The radially contact pressure will be forced by the circulating tube spring, which also traces the rings back in position after deflection. The common force should be 1 – 1,5 N/cm² surface pressure. Due to the design and construction of the components, radial movements of more the 5 mm are possible, without any failure or damage to the seal.
Especially the easy and user friendly maintenance ability, without completely disassembling the machine, is one of the main advantages of segmented carbon rings. The following schematic illustrations show a variety of sealing types. When using segmented carbon rings, the shaft needs to have a good surface quality in order of ensuring a long lifetime. Standard materials are graphite and graphite with antimony impregnations. The circulating tube springs are Hastelloy C4 and will be delivered in a package with the seals.
We are alternative spare parts supplier for segmented seals including the WD and WKA series WD100, WD200. The WD500 series is offered with overlapping and theeth ends with alternative materials for E10K , E12K, E10C, E22 and E49. The WDK, WKA (801, 802, 803)is offered as single piece with titanium bandages, like WDM and others. Lead times vary from 2 days to 4 weeks.
