Mechanical seals for WITTE gear pumps

Mechanical seals for chemical pumps

A variety of seal variations are available for WITTE CHEM chemical pumps. In addition to mechanical seals - depending on the process - magnetic couplings or radial shaft seals are also installed. In individual cases, chemical pumps from the CHEM series can also be sealed threaded shaft seals. The use of seals is determined by the suction pressure, viscosity and temperatures.


Example structure of a WITTE mechanical seal (AD)

  • Wedge
  • Radial shaft seal ring
  • Stationary seal ring
  • Spring element
  • Rotating seal ring
  • Entrance of buffering medium
  • Release of buffering medium
  • Packing ring

  • Wedge

  • Radial shaft seal ring

  • Stationary seal ring

  • Spring element

  • Rotating seal ring

  • Entrance of buffering medium

  • Release of buffering medium

  • Packing ring


Variations of the WITTE mechanical seal

Single-acting mechanical seal (ED)

The single internal mechanical seal (ED) is the standard seal for WITTE CHEM chemical pumps. It can be used for viscosities of up to 50,000 mPas.

Can be used for the following pump types:

  •     [CHEM]
  •     [PURO]

Operating parameters

Pressure suction side:
from Vacuum up to 15 bar(a)
Viscosity:
0,2 – 50.000 mPas
Temperature:
max. 300 °C

Quenched internal mechanical seal

 

The quenched, internal mechanical seal (EQD) is an affordable alternative to classic double seals if the actual operating parameters allow for a single-acting seal, but the medium must be hermetically separated from the atmosphere. Examples include applications according to TA-air or media that reacts to oxygen or moisture.


Can be used for the following pump types:   

  • [CHEM]
  • [PURO]

Operating parameters

Pressure suction side:
from 1 up to 3 bar(a)
Viscosity:
0,2 – 50.000 mPas
Temperature:
max. 250 °C

Vacuum mechanical seal (AD), locked pressureless

The single external vacuum mechanical seal for chemical pumps (AD) is locked without pressure. The locked mechanical seal is specially designed for vacuum conditions on the suction side. It can be used for viscosities of up to maximal 100 Pas.


 

Can be used for the following pump types:

  •     [CHEM]
  •     [PURO]

Operating parameters

Pressure suction side:
Vacuum up to max 2 bar
Viscosity:
0 - 100,000 mPas
Temperature:
max. 250 °C

Double mechanical seal, locked (DD)

The double mechanical seal (DD), locked can be used for viscosities of up to max. 1,000 Pas, because the moving parts of the mechanical seal cannot come into contact with the product. All moving parts are lubricated through the buffering medium. The GLRD (DD) can be used for incoming pressures that may amount to vacuum conditions of up to max. 15 bar.


Can be used for the following pump types:

     

Operating parameters

Pressure suction side:
Vacuum up to max 15 bar
Viscosity:
0 - 1,000,000 mPas
Temperature:
max. 300°C