CJC Desorber / Filter unit: what is it?

Dear all,

This topic we will talk about CJC Desorber / Filter combine unit!

These below questions will be discussed and we will know general about CJC unit.

1) What is CJC?

2) Application?

3) How does it made?

3) How does it operate?

4) Why do we need it?

5) How to use?

…

Now we start:

1) What is it – CJC unit?

Sometime we see it in Stern tube Lub. Oil P&ID dwg:

CJC Desorber/Filter Unit is a combined product used for maintenance of oils. The unit removes large amounts of water and particles from a wide range of lubricants including emulsified oils and EAL’s (Environmentally Acceptable Lubricants).

2) Application:

It is used wide in Marine Applications:

+ thrusters

+ stern tubes

+ rudders

+ controllable pitch propeller

+ Steering gear

+ Gear box

+ Winch

+ Marine crane

+ etc…

3) Why dose our system need it?

During our equipment operate, they will face with some issue as below:

a) Water content in oil: example – shaft corrosion

Water in oil leads to change in viscosity, reduced filter ability, reduced lubricity, formation of rust and bacterial growth and increased degradation of the oil – all factors that lead to reduced lifetime of both system components and the oil. It is very difficult to avoid water contamination in the oil. Humid air enters the system via air vents and is absorbed by the oil. Varying temperatures enhance this process. Cooling water leakages and similar water ingress are also common sources of oil contamination. With water present in system, it will create out:

– Cavitation: Water droplets in the oil evaporate under high pressure, implode and rip part cles off the metal surfaces.

– Corrosion: Water or chemical contaminants in the oil cause rust or chemical react ons, which deteriorate the component surfaces.

b) Particles:
Particle contamination of the oil can only be reduced, not avoided. The contaminants enter the system from the environment (e.g. through vent ng, oil refi lling or repairs), but they are also generated inside the system (abrasion). Every particle in the system can generate more contamination (sand blasting effect). It will lead to:

– Erosion: Small particles in a high velocity oil flow come in contact with metal surfaces and edges, breaking off more particles (sand blasting effect).

– Abrasion: Hard particles jammed between moving parts destroy the surfaces (abrasive wear).

c) Oil ageing: format on of resins, varnish, sludge and acids. Degradat on products result ng from oil ageing occur in both lubricat on and hydraulic systems. This is mainly influenced by oxidation (oxygen), hydrolysis (water) and pyrolysis (thermal decay at high temperatures). In most cases, all of these three factors combined are at play. The degradat on products lead to format on of sludge and / or resin-like deposits. Additionally, an acidification of the fluid occurs during oil ageing process.

4) The advantage of the CJC:

The CJC Desorber/Filter Unit is one unit solving problems with both water and particles.
+ Removal of large amounts of water – even from emulsified lubricants, preventing formation of acid and microbial growth.
+ Removal of particles and sodium
+ Reduced corrosion and wear/tear of rubber made sealings
+ Extended lifetime of both oil and components
+ Prevents uncontrolled shut downs and reduces maintenance costs
+ Environmental friendly solution

5) How does it work?

It has 2 function: Desorber & Oil filter. CJC can combine 2 function or only 1 function. It is belong to your choose.

+ Desorber: The desorption process is based on the principle that heated air can effectively hold large quantities of water. In the Desorber the oil is preheated to 60°C and met by a counter flow of cold dry air. The air is heated rapidly by the hot oil and absorbs any water present in the oil, until the air is saturated. The warm, moist air is then chilled to condense the water out.

+ Oil filter: The filtration process is performed by the separate pump drawing oil from the main system and passing it through the fine filter, exiting from the filter base and back to the main system.