Mechanical seals


Here we primarily classify mechanical seals for water and other lighter applications where the media is not  aggressive or dangerous to the environment, and the operating parameters (pressure and temperature) are  not extremely high. The T2100 mechanical seal with a rubber bellows stands out for its simple design,  reliability, and reasonable price, making it the first choice for many users around the world, as well as in our  country.

At MS PROMCOM, we always have a large selection of diameters (from 18mm to 65mm) and material  options for this seal in stock.

We also offer the T502 seal, which has a more robust rubber bellows for higher pressures, as well as the  unbalanced and balanced T58U/T58B seals, among others. All of these seals meet the DIN 24960 (EN  12756) standard.

For Jugostroj compressors, we always have T109 seal parts in stock, including PTFE and graphite, a  complete rotary assembly, a stationary ring, and a complete seal.

T2100 T109


Of all the manufacturers of mechanical seals, John Crane is the only one to have developed and produced an inexpensive and simple cartridge seal series T4600 that can be used for most standard industrial applications. Already proven worldwide and on our market, this seal is the ideal solution if you want to replace braided packing with a more modern and reliable solution that is easy to install and maintain. It is used for fluids such as clean and dirty water, oil, emulsions, and similar, where pressures do not exceed 15 bar and fluid temperatures are up to 120°C. A major advantage of this seal is that it does not require any measurement during installation or compression to the working length, nor does it require tightening during operation, as is the case with braided packing. It does not wear the shaft and once installed, it operates without any intervention for several years. It achieves significant energy savings compared to braided packing – up to 30% – and reduces the number of people servicing the equipment. It can also be ordered in parts.

Below you can find a brief overview of the seal by industry, which aims only to introduce you to the most  basic John Crane product line. You can get much more information by contacting us. With the technical  assistance of experienced engineers from John Crane, we will try to meet every request you have.


These industrial sectors are subject to the latest API 682 standard, which requires that all seals be in  CARTRIDGE design.

According to API 682, there are three basic types of seals designed for different operating conditions:

  1. Type A seals are used for general-purpose applications and can handle pressures up to 20 bar and temperatures up to 200°C. They are suitable for applications with clean and slightly contaminated fluids.
  2. Type B seals are designed for more demanding applications with higher pressures up to 80 bar and temperatures up to 350°C. They are used for handling corrosive and abrasive fluids and are suitable for applications with moderate to high levels of contamination.
  3. Type C seals are used in the most demanding applications


These industrial branches are subject to the latest API 682 standard, which requires all seals to be in CARTRIDGE design.
According to API 682, three basic types of seals are defined for different operating conditions:
The types of seals according to API 682 that are most commonly used, depending on the secondary sealing element, can be:

  • Type A: with a rotating O-ring on the shaft and an O-ring on the stationary ring
  • Type B: with a rotating metal bellows and an O-ring on the stationary ring (for lower temperatures)
  • Type C: with a stationary metal bellows with a flexible graphite seal on the stationary ring (for higher temperatures)
    In the following two tables, you can see which types of seals JOHN CRANE recommends according to the above division, depending on whether they are intended for the chemical and petrochemical industry or the oil and gas industry:
Type Type A Type B Type C Description
1 5610Q 5615Q Single seal
2 5620P 5625P Dual seal with barrier fluid
2 5620D 5625D Dual seal with external seal for dry running
3 5620P 5625P Dual seal with barrier fluid
3 2800 2800MB Dual seal with gas as sealing fluid
Type Type A Type B Type C Description
1 1648 option 1670 1604 Single seal
2 2648 2670 2609 Dual seal with barrier fluid
2 2648 2670 2609 Dual seal with external seal for dry running
3 2648 2670 2609 Non-contacting external seal
3 3648 3670 3609 Dual seal with barrier fluid
3 2800 2800MB Dual seal with gas as sealing fluid (0-21bar)
3 2800HP Dual seal with gas as sealing fluid for high pressures (21-42bar)

In addition to offering standard JOHN CRANE seals according to API 682, we also provide new solutions specifically designed for your particular case (also according to API 682), as well as seals and parts for direct replacement of existing ones. Of course, we also have seals that have proven to be effective in these industries for years, either with an O-ring as a secondary seal or a PTFE wedge.

Dry Running Gas Seals are the most effective sealing solutions for most compressors, steam turbines, or other equipment designed to work with gas. Traditional sealing methods for these devices, such as double mechanical seals, labyrinth seals, and carbon ring seals, which caused mixing and contamination of the gas with sealing oil and vice versa, have been replaced by newer solutions that do not require expensive maintenance, frequent repairs, and replacements. Gas seals via Laser Groove Technology provide a thin film of gas between the sealing faces, generating less heat on them and reducing wear. Different families of these seals are available for different purposes, such as T28, T285, etc.


The pharmaceutical industry has specific strict hygiene conditions, often sterile environments, and therefore very demanding working conditions. In addition to pumps, the installation of seals is also very common on mixers. To avoid the need for sealing fluid that may endanger the entire environment and the production process, dry running mechanical seals are recommended. They are most commonly used on mixers with vessels, and there are three specific cases of installation:

  • top side installation (vertical installation); the role of the seal here is to retain gas or any vapor within the vessel (reactor), and double seals are used – T151, T153, CK725, CK726, CK736, or CARTRIDGE T7700
  • bottom side installation (vertical installation); here, the seal is completely in the working fluid, but attention must be paid to solid particles and dirt that can accumulate on and around the seal
  • side installation (horizontal installation); here, the seal is usually completely in the working fluid, and standard seals can be used.


In an effort to become a global leader in sealing solutions in this industry, JOHN CRANE acquired the long established leader in this segment, the Finnish company SAFEMATIC.
For this industry, CARTRIDGE seals are recommended, depending on the density (concentration) of the pulp, the following types are recommended:

  • <2% – SAFEMATIC SB1, a single seal with springs located outside the working fluid, in the stationary part, so there is no risk of them being blocked or vibrating due to shaft oscillation. The balanced design of the sealing faces ensures exceptional durability when the pressure suddenly changes. • 3-4% – SAFEMATIC SBW, a single seal with water quenching. It has all the characteristics of SB1, but can withstand higher temperatures and higher density materials.
  • > 4% – SAFEMATIC SB2, a double seal for heavy-duty conditions where the medium is abrasive and highly toxic. Here, the springs are also located in the stationary part, and the sealing fluid, which is inside the seal, flows around the springs, preventing them from rusting and blocking. It is used for high temperatures, and thanks to a specific heat treatment, there is no bending (rounding) of the sealing faces. The allowable axial shaft displacement is 2mm.

Further information, the complete product range, and technical documentation can be found on


John Crane develops new models of flexible couplings every year, and accordingly, we can offer you two families of couplings, within which there are several series and types.


These couplings have been used for many years in various industries worldwide, and they are present in  many companies in our region. We can highlight some of them:

  • NIS-Oil Refinery Pančevo,
  • NIS-Oil Refinery Novi Sad,
  • HIP – Azotara Pančevo,
  • MSK-Kikinda,
  • US Steel Smederevo,
  • NIS-Naftagas,
  • HIP-Petrohemija,
  • FENI Kavadarci (Macedonia), etc.
(L and T series)
(M series)

These couplings are used in a wide range of applications, from small centrifugal to large feed pumps, fans,  compressors, and turbines to conveyor belts (in steel mills, mines, etc.). They are used for powers up to 100  MW and speeds up to 40,000 rpm. The service life of these couplings exceeds that of the equipment they  are used with, so their service life is considered unlimited. The only element that is replaced is the elastic  membrane. The hubs and intermediate shaft (spacer) are not damaged and never need to be replaced.

Based on the drawings with dimensions and working characteristics of the existing couplings (gear, claw,  periflex, with rubber inserts, etc.), equipment measurements, or by filling out our questionnaires, we select  our couplings and offer replacement with complete technical assistance (we provide complete technical  documentation – drawings, working characteristics, etc.).

Standard couplings from John Crane’s product range can be selected, or special couplings can be designed  for a specific user application.


  • No maintenance required
  • No lubrication required because there are no elements in relative motion (as is the case with gear  couplings)
  • No wear of parts
  • No lubrication required (not harmful to the environment)
  • They have the ability to transmit several times the nominal torque (without damage) – In case of membrane rupture, there is no scattering of parts (the coupling remains intact)
  • They can be supplied with torque limiters
  • Connection to equipment via keys on the shaft, flanges, overlap (hydraulic assembly), or clamping rings – Distances between shafts from 3 mm to 10 m

T Series

  • These couplings are considered the safest couplings in the world
  • In case of overload, they exclude the working machine from the drive by breaking the overload collar on the membrane unit
  • Maximum torque up to 96 kNm
  • Maximum speed 24,000 rpm
  • It has a unique central part (Transmission Unit) that is removed from the hubs without moving the  equipment
  • Contains membranes and intermediate shaft
  • According to API 610 and 671 standards (for the oil industry)

M Series

  • Better performance, safety characteristics, and reliability compared to the L Series – Maximum torque up to 470 kNm
  • Maximum speed 25,000 rpm
  • Has a unique central part (Transmission Unit) that can be removed from the hubs without moving the equipment – contains membranes and intermediate shaft
  • According to API 610 standard (for the oil industry)

L Series

  • Basic type of couplings used for all standard industrial applications
  • Maximum torque 235 kNm
  • Maximum speed 5,000 rpm
  • Shaft diameters: from 30 to 347 mm
  • Supplied in a disassembled state

Family of couplings: POWERSTREAM 

A Series

To meet the increasingly demanding market, a new series of couplings with a compact design and toothed rubber belt for somewhat lighter operating conditions has been developed and adopted – the A Series.


  • Easy installation and maintenance – does not require moving the hubs, i.e. the driving and driven machines when replacing the rubber parts of the coupling.
  • Ability to “accept” large device misalignment
  • Absorb a large amount of vibration and thus protect equipment
  • Allow equipment to operate at critical speeds without damage
  • Can transmit torque even when the rubber belt fails
  • Only the condition of the rubber belt is checked
  • Can operate in both directions
  • Do not require lubrication