Grafotherm® WS 9525, WS 9500, WS 9590
for pump shafts and fitting spindles

                                                                  pump shafts            fitting spindles

V_g:                                                          40 m/s                  3 m/s  

P (bar)                                                    40 bar                   100 bar at 1,2 g/cm³
                                                                                200 bar at 1,4 g/cm³
                                                                                325 bar at 1,6 g/cm³

t (°C)                                                  - 200 up to +550°C in water
                                                                  - 200 up to +2000°C in inert atmosphere

pH                                                                         0 - 14

Media:

Resistant against most media. Not applicable against strong oxidants e.g. concentrated nitric acid, sulphuric acid and
perchloric acid and chrome (VI) solutions, alkaline salt e.g. calium chlorate, -nitrate aggressive gases with bromine,
chlordioxide or sulphuric trioxide.

Design:

Grafotherm consists of pure graphite, which has been expanded in a special procedure. This material is densified
to foils without using any binders or fillers and cut in strips. These strips (as mentioned below) can be pressed as
sealing rings into glandbox rings on site. As a rule, we supply finished prepressed rings of Grafotherm strips.

Characteristic features:

• Ductility up to 50% of original thickness at a density of 1,0 g/cm³

• Resilience of approx. 10% of the original thickness

• Continuous elasticity, resistant to thermal shocks, non-ageing, no hardening or softening, no warm- or cold flow

• High heat conductivity, depending on density 100…400 W/K*m

• Low friction value µ = 0,05 - 0,09; self lubricating

• Resistant to radiation 5^.* 10⁶ rad

• Good sectional density, at shafts only very low leakage is necessary.

WS 9525 is the standard quality, whereby WS 9500 is applied in the case of high purity requirements.

The quality WS 9590 with corrosion inhibitor (barium molybdate) is recommended in the case of special requirements
of the corrosion safety, e.g. in the case of long storing periods, long idle running times at water- and vapour fittings of
combinations of high-alloy spindle materials and low-alloy housing materials.

Advantages:

• Wide range of application, thus easy stock-keeping

• No disturbance due to a wrong selection of the gaskets

• Easy mounting, short idle running times, less maintenance service: no resealing, only re-mounting in the case of increased leakage

• Long lifetime at low leakage

• Protection of shafts and spindles

• For fittings, decrease of the glandbox depth is possible

Shapes available:

The following types of Grafotherm WS 9525, WS 9500 and WS 9590 with densities of 1.2 to 1.8 g/cm³
depending on the respective application are available:

• Packing-rings pressed on foil, continuos, with a cut or separated

• Profile rings, e.g. with angular cut for covers

• Profile rings with small cross sections as part of replacement for Elastomer-O-rings

Made of Grafotherm WS 9500:

• Strips with transverse ribs 0,38 mm thick, in 10, 15, 20 and 25 mm width, for self rolling and pressing in the glandbox

• Strips with transverse ribs, 1,0 mm thick with adhesive strip for the sealing of flanges, covers etc.

Special widths on request.