What causes fever of my newly installed mechanical seals?

The newly installed mechanical seals can be operated after testing the static pressure without leakage (minor leakage can be accepted). For those mechanical seals using the springs to transfer torque, the pump rotating directions must be monitored. After the operation of the pump, the leakage of the mechanical seals, heating conditions, unusual sound, the use of auxiliary facilities, pump entrance pressure and vibration conditions needs to be checked. If the pump works well but the mechanical seals have massive amount of leakage, abnormal heat and noises, the causes need to be checked. First, check the wash of mechanical seals and the working conditions and make sure the pressure and flow of the cooling water and other auxiliary facilities work properly. After adjusting the facilities, check the change of mechanical seals leakage and heat circumstance. If the adjustment is invalid, stop the pump immediately.

The errors of a heating mechanical seal come with hot glands and blue smokes from the liquid hydrocarbon.  The reasons of the phenomenon are various.

  • Using the unbalanced mechanical seals in the liquid hydrocarbon pumps of high working pressure and special shaft size will cause big specific pressure on the face.

  • For the balanced mechanical seals, wrong installations, the contact between the shaft steps with rotaries, and high pressure of axial force on the seal faces will cause big specific pressure on the face too.(see the below pic)

  • For high temperature pumps with double-supported structure, the rotor gets extended by soaking in the high temperature media, so the expansion value of axial shell is less than the shaft elongation. One side of the shaft is fixed and thermal expansion is allowed at the other side (free end). Rotary seat is installed in the shaft and the static rings are located on the pump shell by glands.

  • The amount of rinsing fluid is not enough or no rinsing fluid for mechanical seals, the friction heat cannot be reduced as required.

  • The seal face is overcrowded. The friction heat caused by mechanical seals is proportional to the face width.

  • The extremely large amount of spring compressibility causes faces pressure than too big.

  • If the quality of friction pairs is poor, it may cause poor thermal conductivity and the heat cannot be dissipated with the rising seal temperature. The poor quality of carbon comes with bad wearability causing excessive wear. Quench water in the gland turns in to black, tiny carbon particles can be found in it.

  • Gas is in cavity. Mechanical seal is in the dry running condition, working without pump priming.


Top 9 causes of leakage when newly installed mechanical seals operating

Most of the leakages of newly installed mechanical seals comes from the improper installation.

  • The designed face pressure rate is not accurate to meet the requirements.

  • The inaccuracy of the amount of spring compression

  • The seal surface roughness does not meet the standard

  • The seal face flatness does not meet the standard.

  • The seal rings distort due to the pressure and temperature. It damages the flatness of the mechanical seal faces

  • The Seizure of rotary and rotary holder.

  • Rotary and seat is not concentric.

  • The Load factor of balanced mechanical seals is not accurate (always too small)

  • The OD and ID of the metal bellow are inaccurate.