Since 1992, the company produces sealings for pumps and armature from expandable graphite.

 Produkcja Uszczelnień Do Armatur - Agnieszka Russek 


The gland rings from expandable graphite, are the most recent material designed for sealing industrial armature glands and rotodynamic pumps with good working parameters, high reliability and durability, at a reasonable price. Because the material is free of any binders and fillings, it maintains its properties in a wide range of temperatures, pressures and sealing media.


The rings from expandable graphite are used mainly as seals for spindles and shafts

  • in high temperature working armature
  • in high pressure armature
  • in nuclear energy armature
  • in steam armature up 600°C
  • in rotodynamic pumps

Acceptable work parameters


  • from -200°C to  500;°C
  • up to  600°C in steam
  • up to 2000°C in an inert environment
  • up to  200°C pure oxygen


  • armature from 40 Mpa (400 bar)
  • rotodynamic pumps up to 6,3 Mpa (63 bar)

The linear velocity can be determined from "w" factor, it being the multiplication of the operating pressure and the linear slip velocity:

w=p×v         to 40 Mpa×m/s

The number of ring in the chamber

The number of rings in the case is dependent on the sealing pressure, the seal structure and the sealing device. The table below allows us to choose the number of rings in the gland chamber, when the rings height is equal to its width.

Rings with slanting cuts
sealing pressurenumber of rings
up to 44
up to 105
up to 406
rotodynamic pumps
up to 6.34
Closed build rings
sealing pressurenumber of rings
armature and pumps
up to 42
up to 163-4
up to 404-6

The length of the gland chambers can be shortened by enclosing the spacers.

The recommended characteristics of the gland chamber

CriteriaArmaturerotodynamic pumps
Gland chamber:
diameter toleranceH8 to H11H8
roughness Ra2,5 to 6,3max 2,5
spindle / shafts
diameter toleranceh7 to h9h7
radial beatingto 0,08to 0,4
hardness HR-40 to 50

Material selection guidelines

Gland rings from expandable graphite are made in industrial cleanness, with an ash content of 2.0%. For special appliances like e.g. nuclear energy or high concentrated oxygen atmosphere, graphite containing no more than 0.15% is used. They are made only on special orders. If the graphite purity is not specified in the order, the rings will contain industrial levels of ash.

CriteriaUnitIndust purityspecial purity
densityg/cm3from 1,4 to 1,6
density tolerance%5
ash content%to 2,0%to 0,15%
chloride contentppmfrom 50to 20
heat conductivity in 20°C
parallel to the platesW/mk155
perpendicular to the platesW/mk4,8
linear expandability coefficiency
between 20 and 1000°C
residual stress W/g DIN 52 913%minimum 48

Assembly and start-up


After placing the specified number of rings in the gland chamber, pull the choke lightly, move the spindle a few times and tighten the choke until the tension in the gland is reached. (calculate the tension using the torque spanner)

Sealing pressureRing tension in the gland
4 MPa20-30 MPa
16 MPa40-60 MPa
40 MPa70-100 MPa

Rotodynamic pumps

After placing the specified number of rings in the chamber, the screws of the choke need to be tightened manually. After starting the pump and reaching operating parameters, tighten the choke in a way to reach a spill in a range between 50 and 500 drops per minute. It's beneficial to start up the pump for a dozen or so seconds, turning it off for a couple of minutes and repeating the process a couple of times. After running the pump for around half an hour, it's possible to reduce the leakage again. To do that, tighten the screw of the choke by 1/6 of a spin, all while controlling the temperature and the size of the leakage. In case of a rapid temperature increase or interruption of the leakage, immediately loosen the choke. The minimal acceptable spill is dependent on the pumps working condition, but it should be between 10 and 100 drops per minute.

Both in armature and in pumps, it's recommended to use closed up rings, but in situations when it's impossible to use them (e.g. in renovations) they can be replaced with seals cut in one place at a 45° angle. This kind of rings can be parted axially and mounted on a pin or a pumps shaft. Some dissection of the ring on the opposite side of the cut is acceptable. It's important to place the seals in the gland in such a way, that the discontinuities are spaced from each other by 60° or 90°. angles.