Voltol

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Voltol is an oil mixture of rapeseed and mineral oil with reduced viscosity and a lower pour point . The product is produced by electrical cracking with an electrical field under alternating voltage . It is used as a lubricating oil mainly for aircraft and car engines and as a hydraulic oil . It is commercially available in Germany and English-speaking countries under the trade name Voltol-Gleitöl and in Belgium as Electrion lubricating oil.

Chemical basics

Oils consist of long-chain, non-electrically charged hydrocarbon chains . Because of the Van der Waals forces , interactions occur between the chains, causing the chains to adhere to one another. The oils become viscous at low temperatures, stick and turn to wax , and lose the ability to get to where they are supposed to reduce friction. At higher temperatures, the molecules begin to vibrate, the weak van der Waals bridges are broken, the hydrocarbon chains lose their fixation and the oil becomes more fluid again. With alternating current, the Van der Waals bridges can be permanently disturbed, so that the pour point only occurs at lower temperatures and the viscosity is reduced. The tendency of the hydrocarbon chains to adhere can also be reduced by adding rapeseed oil. Rapeseed oil consists of long-chain carboxylic acids and carboxylic acid esters. The carboxy groups are bulky and thus prevent the order of the hydrocarbon molecules. The two factors: the use of electrical alternating current and the addition of vegetable oils can establish the effect of stabilizing the viscosity over a wide temperature range.

Manufacturing

Until 1945, Voltol was produced in double-walled glass cylinders. Copper foils were inserted between the glass walls. High voltage with a frequency of 500 Hz from a transformer was applied to the inner film ; the outer film was at reference potential and served as a return conductor. This created a tension field and a glow discharge of the electric current occurred. The oil to be treated was located in the glass cylinders. First the rapeseed oil was exposed to the alternating current, then the mineral oil was added gradually. The cylinders were rotated so that the oil was evenly exposed to the stress field. Power was supplied via sliding contacts. The use of energy is stated differently: The Enemy Oil Committee estimated 0.5 kWh / kg Voltol, but the annual reports at the time result in two to three kWh / kg.

Mixtures

The following mixtures were used:

  • Main product Endvoltol, consisting of ⅓ rapeseed oil and ⅔ mineral oil in parts by weight, without any other additives.
  • Aero Shell Middle Oil: This middle oil was high in Endvoltol.
  • Voltolized oil: 95% mineral oil, 5% final voltol, in parts by weight.
  • Mixture of ¼ rapeseed oil and ¾ mineral oil in parts by weight: this oil was mixed with rosin oils in France .

Changes in the lubricating properties when using Voltol

In the opinion of the Enemy Oil Committee, the following improvements in lubricating properties were found in normal engines:

  • The oil stagnates at lower temperatures and becomes liquid at lower temperatures than conventional lubricating oil;
  • when the temperature rises, the oils become more fluid;
  • the lubricity is improved;
  • the engines become cleaner because voltolized oil dissolves the oil sludge better.

In the case of aircraft engines, the available data showed that the proportion of Voltol in the lubricating oil should not be more than 5% by weight. A higher proportion of vegetable oil would burn at the prevailing high temperatures and leave too much residue.

Company history

In 1907 Alexandre de Hemptinne (born April 17, 1866 in Ghent ; † December 7, 1955 there) founded a factory in Wondelgem , since 1977 Ghent-Wondelgem, which processed fish oil . De Hemptinne was a chemist , worked for two years at the University of Leipzig under Wilhelm Ostwald and received his doctorate there in 1893 on the basis of a dissertation on the electrical conductivity of the flame and the gases. Since 1902 he worked as a professor at the Catholic University of Leuven . In 1911 he began to produce a mineral oil for the lubrication of diesel engines for the first time, which lubricated better than the previously used, but chemically very stable fish oil. He had the process patented.

First World War

Continuation of production in Ghent

During the First World War, de Hemptinne was requested by the German occupying forces to restart the decommissioned Elektrion plant and to make oil production available to the occupying forces, otherwise he would be deported to Germany. De Hemptinne refused. In contrast to the historian Henri Pirenne , the threat was not carried out, but de Hemptinne's factory was dismantled and taken to Potschappel , since 1921 Freital -Potschappel. A device that was difficult to transport was left in Antwerp . The factory in Wondelgem was liquidated. In Antwerp, the former employees Lèopold de Cavel and Michel Roegiers resumed production in agreement with de Hemptinne.

The German chemist Walther Nernst , who completed his habilitation under Wilhelm Ostwald in 1889, and the physicist Josef Stern were commissioned to restart the factory in Freital-Potschappel. The brothers Josef and Leopold Stern and their brother-in-law Jacques Sonneborn, who were involved as founders in the Hamburg oil works Stern-Sonneborn AG , founded Elektrion Öl-GmbH in Hamburg. In 1917, Elektrion Öl GmbH submitted a building application to build a factory hall in Birkigt, since 1923 Freital-Birkigt, and built it from 1919 to 1921.

Between the world wars

Production hall 1921–1946

As of January 23, 1922, the company no longer used the product and company name Elektrion, but operated the company under the name Deutsche Voltolwerke-GmbH. In 1924, the Voltolwerke returned the reactors from Wondelgem, and de Cavel and Roegiers were able to rebuild the factory in Ghent at the new location at Nieuwewandeling 68. Voltol found a prominent use in the five twelve-cylinder engines of the airship LZ 126 , which Hugo Eckener personally transported from Friedrichshafen to Lakehurst on October 12, 1926 . In 1925 Mineralölwerke Rhenania AG took over Ölwerke Stern-Sonneborn AG and continued to run it under the name Rhenania-Ossag Mineralölwerke AG. As of August 19, 1926, Deutsche Voltolwerke GmbH was merged with Rhenania-Ossag Mineralölwerke AG and was continued as a dependent department under the company name Werk Freital, Voltolwerke department. Voltol was not delivered to Belgium.

Second World War

In 1939 Rhenania-Ossag was subordinated to the Central Bureau for Mineral Oil as part of the war economy. The following quantities of Endvoltol were produced during the Second World War: 1993 t, 1598 t, 1621 t and 985 t (1939 to 1942). The main customers were the Luftwaffe.

Further development

A major benefit of using electrically treated rapeseed oil was that it reduced the build-up of oil carbon in the cylinders. The disadvantage was that the piston rings began to stick together. Therefore, between August 1942 and March 1943, tests were carried out in the Amsterdam laboratory of the Royal Dutch Shell to determine to what extent the amount and type of non-soluble oil components contributed to the sticking of the piston rings. Electricity with a frequency of 7500 Hz was used instead of the 500 Hz common in Freital. The oil sludge that appeared in the laboratory experiment was viscous and pulled threads, the Freital oil sludge was rubbery. Carl Zerbe (* February 13, 1894; † April 7, 1985), who during the Second World War as the former research director of Rhenania-Ossag Mineralölwerke AG was responsible for the supervision of the laboratories of the Royal Dutch Shell, made the Freitaler oil sludge for gluing the Piston rings responsible. Zerbe wanted to transfer the knowledge gained in the laboratory to the production process in Freital, in particular he wanted to expose rapeseed oil and mineral oil to alternating current at the same time. Zerbe never received any oil produced in this way. Further attempts were planned, but did not take place.

Allied intelligence

In 1941 the Rhenania-Ossag-Werke were first recorded as an oil target and shown in the British District Target Map No 82 . The designation was GQ 1612, where G stood for Germany and Q for an oil target. While the cast steel works in Freital-Döhlen were correctly registered as a steel target with the designation GF 2259, the Voltol works in southern Freital-Deuben on the border to a small industrial area in Freital-Hainsberg was drawn. However, the legend of the map correctly mentioned that a special oil for the air force was produced in the Voltol plant.

In June 1943, the US Enemy Oil Committee, Western Axis Subcommittee, only showed the Voltol plant in one footnote. In a new report dated December 15, 1943, the reference was retained, but the subcommittee considered the plant to be probably non-existent, but if it did exist, an annual production of 70,000 t could be expected. On June 3, 1944, the work was proven to be reliable and possibly existed. As in the production of synthetic fuel, brown coal is used.

On July 21, 1944, the 7th Photographic Reconnaissance Group took an aerial photo of Birkigt at a scale of 1: 6,000. There, the Bühler Brothers GmbH, Mühlenbauanstalt und Maschinenfabrik at Gitterseer Straße 13, located to the south-east, and the neighboring art furniture factory Anton Schega, were handwritten as the target center. In a second aerial photo from the same day on a scale of 1: 32,000, an arrow points to the Bühler machine factory as the target center. The two aerial photos were included in a Target Information Sheet. Voltol was aptly referred to as vegetable oil that is treated with electricity, mixed with other lubricating oil, where it ensures a constant consistency at extreme temperatures and is therefore important for aircraft lubricants. The annual production was given as 6,000 t, but the significance is greater than the amount suggests.

The bombing of Freital-Birkigt on August 24, 1944

In the deployment order for the 486th and 487th Bombing Group of the 3rd Bombardment Division of the 8th Air Force - “Mighty Eight” - the importance of the target was pointed out: Although the Voltol plant is only the seventeenth of 26 targets of the 8th Air Force, be it but the only factory in Germany that refines high-quality aircraft lubricants and has never been attacked.

The 3rd Bombardment Division flew to three destinations on August 24, 1944: Kiel , Freital and Brüx (today: Most / Czech Republic). The 486th Bombing Group flew from Sudbury, the 487th Bombing Group from Levenham. Both groups of bombers united in Suffolk on the east coast and flew to Cottbus via Helgoland , Cuxhaven and Magdeburg . There they returned and flew west again towards Dresden. They just bypassed the anti-aircraft guns stationed there and released 500 explosive bombs between 12:59 p.m. and 13:05 p.m. over Dresden-Mockritz . The bombing was done with great accuracy. 47% of the high explosive bombs hit within 150 m of the target center.

The anti-aircraft defenses, which consisted of too few guns, only fired weakly and inaccurately.

Bühler machine works bombed

However, it was not the alleged Voltol works that were hit, but the Bühler machine factory and the Anton Schega furniture factory, which was completely destroyed. The Otto Hänsel machine factory, 350 m east of the Voltol plant, was badly hit, but not completely destroyed. It manufactured candy wrapping machines, drop rolling machines and the waxed paper required for wrapping. 51 dead and 40 injured at the Bühler machine factory and 82 dead and one seriously injured at the Hansel machine factory. There were a total of 244 fatalities. The Voltolwerk got away with minor damage and no direct hit.

Two and a half hours after the attack, the 7th Photographic Reconnaissance Group took an aerial photo on a scale of 1: 10,200 showing the burning Bühler machine factory and the undamaged Voltolwerk. At 5:00 p.m., the English radio reported that the Freital Shell factory had been destroyed. In the evaluation report of the 3rd Bombardment Division of August 25, 1944, the detonations of the "oil refinery" were assigned as follows: Boiler house: possibly a direct hit; Main production building: a possible hit, a near hit; Administration: a direct hit and a near hit. On September 4, 1944, the Joint Oil Targets Committee summarized the result: “Of the only known factories in German Europe that use this process (meaning the Voltol or Elektrion process), one in Freital near Dresden is from US 8th Air Force recently badly damaged. The other one in Ghent is no longer in German hands. ”There was no third Voltolwerk suspected in Hamburg.

consequences

Although the factory remained intact, Voltol was no longer produced in Freital after the end of the war. In the factory hall, VEB Chemische Werke Bussard produced, among other things, the ski wax “Drix”. The hall is empty and is partly used as a workshop. The Elektrion works resumed operations in Ghent in 1946. In 1958 they built a new office and laboratory building. You have become the largest independent manufacturer of lubricating oil in Belgium and produce electrion lubricating oil in many qualities. Voltol is offered as Shell-Voltol lubricating oil.

literature

  • Götz Bergander: Dresden in the Air War , special edition, Würzburg 1998.
  • Katrin Schulze: GQ 1612. What led the Allies to Freital-Birkigt on August 24, 1944 . Schulze, Freital 2011.
  • Karl Söhnel: The valley of work in Rudolf Schumann (Hrsg.): Communications of the Landesverein Sächsischer Heimatschutz , Dresden 1927.

Individual evidence

  1. ^ Annual report 1939 of the Rhenania-Ossag Mineralölwerke AG Freital works, Voltolwerke dept. (PDF) (No longer available online.) 1939, p. 11 , formerly in the original ; Retrieved April 25, 2017 .  ( Page no longer available , search in web archives )  Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice.@1@ 2Template: Toter Link / fischer-tropsch.org  
  2. ↑ a b Katrin Schulze: GQ 1612. What led the Allies to Freital-Birkigt on August 24, 1944 . Schulze, Freital 2011, p. 36.
  3. ^ Karl Söhnel: The valley of work in Rudolf Schumann (ed.): Communications of the Landesverein Sächsischer Heimatschutz , Dresden 1927, p. 200.
  4. ↑ Katrin Schulze: GQ 1612. What led the Allies to Freital-Birkigt on August 24, 1944 . Schulze, Freital 2011, p. 25.
  5. ↑ Katrin Schulze: GQ 1612. What led the Allies to Freital-Birkigt on August 24, 1944 . Schulze, Freital 2011, p. 31 f.
  6. ↑ Katrin Schulze: GQ 1612. What led the Allies to Freital-Birkigt on August 24, 1944 . Schulze, Freital 2011, p. 29 f.
  7. ↑ Katrin Schulze: GQ 1612. What led the Allies to Freital-Birkigt on August 24, 1944 . Schulze, Freital 2011, p. 33.
  8. ^ Götz Bergander: Dresden in the air war . Special edition, Würzburg 1998, p. 25.
  9. ↑ Katrin Schulze: GQ 1612. What led the Allies to Freital-Birkigt on August 24, 1944 . Schulze, Freital 2011, p. 48.
  10. ^ Götz Bergander: Dresden in the air war . Special edition, Würzburg 1998, p. 59.
  11. ↑ Katrin Schulze: GQ 1612. What led the Allies to Freital-Birkigt on August 24, 1944 . Schulze, Freital 2011, p. 115.
  12. ↑ Katrin Schulze: GQ 1612. What led the Allies to Freital-Birkigt on August 24, 1944 . Schulze, Freital 2011, pp. 90f.
  13. ↑ Katrin Schulze: GQ 1612. What led the Allies to Freital-Birkigt on August 24, 1944 . Schulze, Freital 2011, p. 126.
  14. ↑ Katrin Schulze: GQ 1612. What led the Allies to Freital-Birkigt on August 24, 1944 . Schulze, Freital 2011, p. 128.
  15. ↑ a b Katrin Schulze: GQ 1612. What led the Allies to Freital-Birkigt on August 24, 1944 . Schulze, Freital 2011, p. 34.
  16. ↑ Katrin Schulze: GQ 1612. What led the Allies to Freital-Birkigt on August 24, 1944 . Schulze, Freital 2011, p. 90.
  17. ↑ Katrin Schulze, GQ 1612 What Drew the Allies to Freital-Birkigt on August 24, 1944 , Freital 2011. p. 35.