Solvent degreasing

Hermetically sealed solvent degreasing technologies for exceptional performance under vacuum

The closed-circuit industrial cleaning process with modified alcohol, AIII hydrocarbon or perchloroethylene represents the ideal technology for applications where the aim is to achieve the highest cleaning results at the lowest possible running costs with consistency being the key objective.

Firbimatic solvent systems are available in standard and bespoke designs.

Before suggesting a solution, we thoroughly analyse the requirements and specific expectations of each individual application. Although organic and inorganic contaminants display different characteristics, our experience shows that even the most difficult can be successfully removed during treatment which may involve a sequence of spray, immersion and vapour stages. By drying under vacuum in a sealed environment all residual solvent is recovered making consumption practically nil.

Firbimatic solvent systems are especially effective for geometrically challenging parts which may demonstrate features such as blind or through holes, fine threads and internal complexities.

Solid contaminants including dust, swarf and inorganic salts are removed efficiently by mechanical washing action including basket oscillation/rotation and kinetic energy afforded by spray and /or ultrasonic energy supported by correctly specified mechanical filtration.

Excellent cleaning results are also repeated with non-metallic materials, especially synthetic plastics for aeronautical, medical and precision machining applications as well as electronic assemblies.

SOLVENT DEGREASER TYPICAL WASHING CYCLE

Firbimatic Metal Cleaning Division solvent systems perform the complete washing and drying cycle inside an hermetically sealed process chamber into which one or more component baskets have been introduced. Based on the type of solvent or the process selected all, or just some of the cleaning phases listed below, are performed under vacuum:

Pre-wash

When the cycle is initiated the process chamber is placed under vacuum and a brief pre-wash is performed with solvent sprayed at high pressure directly onto the parts. This solvent charge is sourced from the main holding tank (T1). Upon completion of the pre-wash the solvent, which now contains 90% of the contaminants in solution, is then directed to the system’s integral distillation unit which purifies the liquid by fractional distillation.

Main Cleaning

For components with complex geometric features or for high volume “bulk” items a main wash with full immersion is essential. Solvent is again introduced into the process chamber from the main holding tank (T1). Basket manipulation (oscillation or rotation) plus the addition of further mechanical agitation by spray under immersion and/or ultrasonic energy remains an option at this point.

During this phase the solvent can also be mechanically filtered before it is returned to T1. In a continuous process solvent from T1 is directed to the distillation unit where it is gradually distilled and the purified solvent returned to a second tank (T2) in readiness for a final liquid clean of 100% pure solvent.

SPRAY RINSE

Where circumstances demand pure solvent from T2 can be introduced into the process chamber by spray action.

Vapour phase

In the final stage of the cleaning cycle and, in preparation for the subsequent drying phase, solvent vapour is directed into the process chamber.

The vapour condenses on the component parts leaving them totally contamination free and simultaneously heating both components and chamber in readiness for the final vacuum drying phase.


Drying phase

Pressure within the process chamber is further reduced which results in a lowering of the solvent boiling temperature. Residual liquid solvent immediately evaporates and the solvent laden air from the chamber is passed through a refrigerated air cooler at -20 degrees Celsius where the solvent vapour is condensed and returned to the solvent holding tanks.

For systems utilising perchloroethylene the chamber solvent concentration is reduced to <1gm/m3 in accordance with EN12921/4. This is accomplished by directing the air stream over activated base carbon - the carbon adsorption unit. The concentration is monitored via a PPM metering system.

All Firbimatic systems ultilise a Siemens S7 PLC programmer for selecting a wide range of different cleaning programs as well as auto-check and monitoring systems of the main functions. The clear digital display provides cycle progress and system status for maintenance purposes.