FRIESS oil separator Skimmtelligent at degreasing bath
A manufacturer of components for weaving machines produces many small parts. Many of the parts have to be hardened. After the quenching in the oil bath the parts have to be washed for further treatment. The small metal parts are stored in baskets and will be dipped into the oil bath in the basket. Because of this storage the parts contain a lot of oil before they are washed in the washing solution.
The problem
The company used an oil skimmer model 3H for more than 15 years in order to remove the oil from the washing water. The oil skimmer operated during the night shift. During the night shift, they stopped the quenching and washing process. The continuous removal of the floating oil from the washing water made sure that the lifetime of the washing water was very long and the cleanliness of parts was satisfying. Because of changing to three-shift production, there was no time for the oil to settle on the surface of the washing water. The continuous production process caused continuous turbulence in the washing water, and the tramp oil did not settle on the surface of the washing water. For this reason, the oil could not be removed with the oil skimmer.
Because of the high percentage of oil in the washing water, the company had to change the washing water once per week. In addition to that the parts were not 100 % clean after washing process. The production manager was looking for a new separation system in order to remove the oil continuously during the washing process.
- Due to the high level of oil in the washing water, the washing water had to be changed weekly.
- In addition, the parts were not 100% clean after washing. After the washing process, some oil stains could still be seen on the parts.
- The management therefore looked for a new system to continuously remove the oil during the washing process.
The solution: Skimmtelligent oil separator
Because of the good experience with the oil skimmer 3H the production manager contacted the representative of Friess GmbH. The area representative recommended using an oil separator type Skimmtelligent 20 in order to remove the oil from the washing water. With the help of a diaphragm pump and a floating suction device, the system pumps continuously oily washing water from the degreasing bath. The diaphragm pump has the big advantage that the small oil droplets will not be destroyed during the pumping process. The separation of the oil droplets from the washing water is much easier if the oil droplets are bigger. The reduction of the volume of the oil droplet by 50 % reduces the uplift of the oil droplet by 75 %. That means the smaller the oil droplet the slower the separation process and vice versa. The bigger the oil droplet is the better is the separation process. That is the reason why every Friess separator Skimmtelligent is equipped with a positive displacement pump instead of a centrifugal pump.
Compressed air diaphragm pump as feed pump
The oily washing water flows into the first separation chamber in the oil separator Skimmtelligent 20. Heavy solids with a specific weight >1 will settle on the bottom of the first chamber. The collected sludge can be drained by a ball valve out of the tank. The oily washing water flows over a baffle into the separation chamber with coalescing media. The washing water flows from the top to the bottom towards the outlet chamber.
Settling chamber for coarse dirt particles
The bigger oil drops remain directly at the surface. Smaller fine dispersed oil droplets flow with the washing water through the coalescing media. The small droplets touch the coalescing media and will stick on the surface of the coalescing media. Several small oil droplets will grow on the surface of the coalescing media to one big oil drop. The lifting power is multiplied and the big oil drops will rise to the surface.
Separation chamber with coalescence insert
The oily washing water flows into the first separation chamber in the oil separator Skimmtelligent 20. Heavy solids with a specific weight >1 will settle on the bottom of the first chamber. The collected sludge can be drained by a ball valve out of the tank. The oily washing water flows over a baffle into the separation chamber with coalescing media. The washing water flows from the top to the bottom towards the outlet chamber. The bigger oil drops remain directly at the surface. Smaller fine dispersed oil droplets flow with the washing water through the coalescing media. The small droplets touch the coalescing media and will stick on the surface of the coalescing media. Several small oil droplets will grow on the surface of the coalescing media to one big oil drop. The lifting power is multiplied and the big oil drops will rise to the surface.
Oil-free reflux for reuse
The clean washing water flows underneath a baffle into the next chamber and from there by gravity through the return hose back into the degreasing bath. The oil that floats on the surface of the separation chamber is removed from time to time fully automatically with the oil skimmer model 1U.
The built-in PLC allows different settings for operation time and idle time. With correct setting of both times, the water content in the removed oil is as low as possible.
Scaling through runtime control
In addition to that, the PLC allows setting the operation time and idle time for the pump. Specially in case that the oil has a high specific weight, the separation performance of the oil separator Skimmtelligent maybe improved when using longer idle time. The capacity of the pump can be adapted to customers’ needs. High capacity allows removing big oil volumes from the washing water surface. At low capacity of the pump, the separation performance in the oil separator Skimmtelligent is improved.
delivery rate of the pump
The waste air from the diaphragm pump is induced into the separation tank. A needle valve allows setting the air volume so that the fine air bubbles will cause additional uplift for the oil droplets. The small air bubbles are able to rise the oil droplets to the surface.
The result: triple the service life of the washing water
- By using the Skimmtelligent oil separator, the service life of the wash water has been tripled from just one week to three weeks.
- At the same time, the washing results have been significantly improved. The staining on the parts has completely disappeared.
- The oil content in the washing water has been significantly reduced.
- At present, around 20 liters of oil are separated from the washing water every day using the Skimmtelligent oil separator.