Архив за месяц: Февраль 2022

Restoration repair of SGDU (dry gas dynamic seals)

In November 2021, the company R&PC «ANOD» received a batch of dry gas dynamic seals manufactured by EagleBurgmann, operated at Yuzhno-Priobsky GPP LLC, for restoration repairs.

Photo 1. The appearance of the SSDU after the repair.

 Technical characteristics of seals:

  • Type of seals: tandem, unidirectional rotation.
  • Shaft diameter, mm: 98.
  • Gas temperature, max (°C): -40…. +190.
  • Pressure, dynamos. ,MPa: 1,7.
  • Pressure, stat., MPa: 7,8.
  • Nominal number of compressor rotor revolutions per minute: 13100.
  • The material of the friction pair rings: silicon carbide.
  • Pumped medium: associated petroleum gas.

The seals were dirty, the rings of the friction pairs had wear. Some metal parts had erosion damage. Polymer sealing rings have lost elasticity. During the repair, the seals were cleaned of dirt. Springs, fasteners, polymer sealing rings were replaced. Damaged metal parts are manufactured again. The rings of the friction pairs were repaired, followed by the application of a diamond-like coating and gas-dynamic grooves (photo 2).

Photo 2. The application of gas-dynamic grooves to the rotating ring of the friction pair.

After successful factory tests in December 2021, the seals were transferred to the customer for further operation.

Wear and damage of friction pairs in the form of chips from anti-turn pins

The company R&PC «ANOD» received for repair a set of dry gas dynamic seals manufactured by the company «TREM-Kazan» operated by the gas transportation division of LLC «Gazprom Transgaz Ukhta».

The appearance of a dry gas dynamic seal after the repair

Photo1. The appearance of a dry gas dynamic seal after the repair

Technical characteristics:

  • Type of seals: tandem, reverse rotation.
  • Shaft diameter, mm: 188.
  • Pressure, dynamos. ,MPa: 5.51 — 7.21.
  • Pressure, stat., MPa: 6.03 — 7.9
  • Nominal number of compressor rotor revolutions per minute: 5250.
  • The material of the friction pair rings: silicon carbide.
  • Pumped medium: natural gas.

The seals were dirty, the rings of the friction pairs had wear and damage in the form of chips from the anti-turn pins. Polymer and rubber O-rings have lost elasticity. During the repair, the seals were cleaned of dirt. Springs, fasteners, polymer and rubber sealing rings were replaced. The damaged metal parts were manufactured again, some of them were coated with a special coating that allows to increase the service life of the seal. An example of such a detail is shown in photo 2.

Dynamic sleeve of dry gas-dynamic seal with wear on the working surface.

Photo 2. Dynamic sleeve of dry gas-dynamic seal with wear on the working surface.

The damaged rings of the friction pairs were replaced with new ones, followed by the application of a diamond-like coating. After successful factory tests in December 2021, the seals were transferred to the customer for further operation.