Floating end seals

Floating end seals

TRIZ® floating seals (PU) are used to seal compressor rotors. Satisfy the requirements of the API 617 standard (Certificate No. ODC1820-0749 / 1)


• high sealing ability;
• high bearing and damping capacity;
• reversible with non-reversible properties;
• long overhaul life;
• low wear, stability of gaps;
• do not require replacement of the oil system, using the standard one.


TRIZ * PU contain six reversible pads with non-reversible properties, an additional damper and an elastic ring of stiffness, with which carrying capacity (up to 40%) and stiffness (up to 20%) in a wide rangecan be changed.
The damping pads installed in the outer floating ring ensure its safe hold and effectively dampening of the oscillations of the rotor. In the process of damping the rotor vibration, three oil films with feedback are involved: between the shaft and the pad; between the block and the outer floating ring; oil film of the damping cavity of the outer floating ring. The principle of operation of the elastic ring stiffness based on the fact that it alternately contacts its inner and outer surface with the tabs on the floating ring and on the seal housing. The cross section of the elastic ring, the dimensions and the number of protrusions is chosen in such a way that when the load on the floating seal ring exceeds the force of its pressing against the body, the elastic ring bends within the gap between the floating ring and the seal body. In this case, from the side of the elastic ring, a reaction force arises, which acts on the floating ring and is directed opposite to its displacement. This creates additional rigidity of the seal assembly.

Combined sealing units

Combined thrust-sealing units of compressors combine the functions of a thrust bearing and a terminal floating seal (oil – gas seal).


• an increase in operating efficiency, due to a decrease in the amplitude of the rotor vibration in transient conditions;
• increase in the overhaul mileage of the compressor up to 12 years;
• increase in the reliability of the bearing support, by eliminating wear of the shaft or babbitt surface of the pads during start-up, work at low revs and stop;
• reducing the inter-support distance allows to increase the rigidity of the rotor, improve its dynamics, reduce the axial dimensions of the compressor, reducing its intensity and cost;
• reducing the amount of pumped oil and reducing the power of oil pumps;
• reduction of friction power losses.

Design features

For the perception of the rotor weight and variable dynamic forces from its vibration a thrust damper bearing is used. The bearing works on sealing oil and has three reversible damping pads 1. The compression cavity is sealed using an oil-gas ring 2, which is a slit seal with a hydraulic shutter: a continuous film of oil flowing in the gap between the shaft and the inner sealing surface of the ring, prevents gas breakthrough from the compression cavity. The ring “oil-gas” is pressed against the end surface of the box on the ground-in sealing belt. A mixture of barrier oil that has passed through the “oil-gas” ring and gas that has passed through the labyrinth seal enters the oil diverter and then to degassing, from where the oil returns to the oil tank and the gas is fed to the compressor suction. Pre-compression of the ring to the sealing belt is carried out by means of springs 3. The heat generated in the node is removed by the oil flow passing through the damper bearing and the annular gap formed by the shaft and the surface of the sealing ring 4 into the body cavity having holes for removing the low-pressure oil into drain pipe.

Special seals

TRIZ develops, manufactures and supplies other types of seals:
• gas pulse seals;
• segment seals;
• mechanical seals;
• stuffing box seals;
• impulse seals.

Delivery terms

Seals are available on request for a given installation dimensions and operating conditions in a short time.
Warrantyperiod – 24 months.