US2110780A - Process of treating drying oils to - Google Patents

Description

March s, 1938. B H THURMAN 2,110,780

PROCESS OF TREATING DRYING OILS TO BODY SAME FOR VARYNISH AND OTHER USES Original Filed July 19, 1933 F grz Ja/ A y rim/r INVENTOR M WNEYQ Patented Mar. 8, 1938 UNITED STATES PATENT OFFICE PROCESS OF TREATING DRYING OILS TO BODY SAME FOR VARNISH AND OTHER USES Application July 19. 1933, Serial No. 681,048 Renewed August 30, 1937 6 Claims.

This invention relates to aprocess of treating fish and vegetable oils for the purpose of bodying them or preparing them to be used in the paint and ,varnish industry and for making enamel, linoleum, etc.

Heretofore, oils have been heated in open kettles over a fire for the purpose of bodying them. This requires a high degree of skill on the part of the operator as the oil is not sufliciently bodied if the heating is not carried far enough and the oil becomes darkened if it is exposed to the air too long at the elevated temperature.

It requires a long time to impart suflicient 'body to the oil by the former heat treatment. For

example, it requires several hours to increase the specific gravity of linseed oil.from about 0.936

to 0.962 and the viscosity from about 2.2 to 47 by the Ford cup test viscometer, in this old way.

During this long time of treatment the oil often becomes discolored to an objectionable extent.

Also, gums or resins that are added to the vegetable oils in making varnish, etc. usually a have to be heated to 550 F. to 600 F. to remove volatile materials that will not mix satisfactorily with the vegetable oils in varnish making. They sometimes amount to 10% to 20% of the weight of the gums or resins. If these volatile products are not removed they cause the varnish to become cloudy.

By the present invention oils, gums and resins that are to be used in varnish and other industries are heat-treated in such a manner that the proper amount of body is imparted to them or the desired amount of volatile materials is re=- moved very rapidly without imparting the other usual objectionable properties.

In carrying out this invention the oil or gum to be treated is passed rapidly through a'heated coil under pressure where it undergoes consid- 40 erable stirring or agitation while it is being heated and it is then permitted to expand into a receiver at a lower pressure whereupon the volatile constituents flash into vapor.

The invention will be explained in connection 45 with the accompanying drawing which shows an arrangement of apparatus for practicing the process. In the drawing Fig. 1 is a somewhat diagrammatic arrangement of apparatus for carrying out the invention and Fig. 2 is a longi- 50 tudinal section on an enlarged scale partly broken away showing a modification of one of the details,

In the drawing reference character i indicates a tank or receptacle for the material. This tank is provided with a stirrer and may be heated in any convenient way, if desired.

- I1 is provided on the outer end of the support l5 A pipe 3 having a valve 4 leads from the lower portion of the tank I to a pump 5 from which a pipe 6 leads to a coil 1 in the heater 8. The lower end of the coil 1 opens into an automatic heat regulator 9. 5

The heat regulator 9 comprises an elongated hollow member ID extending across the lower end of the heater 8, with an inner tube I I anchored at its closed end l2 in the hollow member In. The

other end i3 of the tube II is open and the walls 10 are slitted and spread out so that the ends of the slits contact with the inside surface of the hollow member ID leaving openings for material to pass from the annular space l4 between the tube II and member ID into the tube ll. 15

One end of the heat regulator 9 is held in adjusted position by the threaded support l5 passing through a threaded opening IS in a wall of the heater 8. An enlarged head or hand wheel for'turning it. The inner end of the support l5 terminates in an enlargement l8 revoluble in a recess I9 provided therefor at the closed end of the member l0, so that the heater 9 can be moved longitudinally into difierent positions by means 25 of the support IS.

The end of the member 10 opposite the support 85 carries a stem or extension 20 which extends through an opening 2| in the wall of the heater 8 and supports that end of the heat regulator 9. A valve 22 is fixed on the outer end of the stem 2| in a housing 23 that is attached to the wall of the heater 8 and carries a valve seat 24. A pipe 25, having a valve 26, for fluid fuel, such as gas, is connected to the housing 23 on the side of the valve-seat 24 opposite the valve 22. An outlet pipe 21 leads from .the other side of the valve seat 24 to the burner 28.

An outlet pipe 30 having a valve 8| leads to a junction 32 from which a pipe 33 having a valve 34 leads to a nozzle 35 in an expansion chamber 36. A cylindrical extension 3'! having its lower endopen surrounds the nozzle 35. The expansion chamber is provided with a stirrer 38 and a valved outlet pipe 30.

An outlet pipe 40 for gas or uncondensed vapors leads from the upper portion of the cham ber 36 to a condenser 4i cooled by the cooling coil 42. A valved outlet pipe 43 for condensates is connected to the lower portion of the condenser 4| and a pipe 44 for uncondensed gases leads from this condenser to a liquid seal tank 45.

A pipe 46 having'a valve '41 leads from the junction 32 to the tank l. A pipe 48 having a.

, valve 49 leads from the pipe 3 to a coil 50 in the from the coil 50 to the pipe 3 on the other side of the valve 4 from the pipe 48.

In the modification indicated in Fig. 2, the pipe 30 leads to a jacket 55 surrounding the pipe 3 so that the material flowing through the pipe 3 becomes heated by the hot material passing through the pipe 30.

In carrying out the invention the oil or other material to be bodied'or heat-treated is introduced into the tank I through the opening I and may be heated to some extent in this tank, if desired. The oil passes from the tank I through pipe 3 to the pressure pump 5 and thence to the heating coil I. The pressure in the coil 1 is maintained at the desired point to prevent or limit volatilization or constituents by regulating the valve 3| or by use of a properly restricted nozzle in the tank 36.

The oil, or other products, is heated to the desired extent in the coil I by the products of combustion from the burner 28, the waste products of combustion escaping through the outlet 8'. The material rapidly changes direction of travel in the coil I, thus causing the same to be stirred or agitated so that it is uniformly heated. The heated material passes from the coil 1 into the annular space I4 in the heat regulator 3 and thence through the passages I3 into the tube II from where it passes through the pipe 36 to the nozzle 35. The release of pressure at the nozzle 35 causes volatile constituents to flash into vapors leaving the unvaporized portions inthe tank 36,

from which they may be withdrawn through the outlet 39. The vapors pass through the pipe 40 to the condenser 42, from which the condensates may be withdrawn through the outlet pipe 43. Uncondensed vapors or gases pass out through the pipe 44 and liquid seal 45.

The heat regulator 3 is automatic as increased temperature causes the member II to expand and move the valve 22 nearer its seat 24, thus shutting off a portion of the fuel gas entering the burner 28 from the pipe 25. A decrease in the temperature of the heater 3 causes it to contract and move the valve farther from its seat 24, thus admitting more gasto the burner 23. By adjusting the support IS, the temperature may be regulated at any desired point.

The valve 4 may be closed and the valves 43 and 52 opened so that the material on the way to the pump 5 from the tank I passes through the coil 50 and is thereby heated by the hot material in the tank 36. The stirrer 33 facilitates transfer of heat from the hot material in the tank 36 to the cold material in the coil 56.

Instead of providing the coil 56 in the tank 35, the jacket 55 (Fig. 2) may be provided so that heat is transferred from the material as it passes from the heat exchanger 3 to the nozzle 35.

In case it is desired to pass the material through the coil 1 more than one time before it is passed to the tank 36, this may be done by closing the chamber 36. A pipe 5I having a valve 52 leads 1 fied. When so treated it loses its property of becoming solidified by heating it to the temperature and for the time required for bodying it. This treatment avoids the necessity of adding other oils, such as linseed or soya bean oil, or resins to it to enable it to be cooked or boiled without solidifying. Also, by heat-treating China-wood oil, as described, and bodying it by boiling, it does not become crinkled or frosted when it dries so that it is suitable for making varnish .or lacquer.

It is commonly believed that bodying oils results not only because of removal of volatile constituents but also because polymerization takes place during the heating. Even a very short time of heating, as described herein, appears to produce both of these results. Polymerization increases the water-proofing qualities of the oil and permits the use of cheaper gums or re'sinsthan kauri or pontiac in making varnishes with the oils.

By the present invention ';the oil is heatedand bodied very effectively and bfficiently in an economical manner. It requires only about six to ten minutes to increase the temperature from room temperature to the desired temperature which is about 580 F. for most oils that are used in making varnishes. However, on account of the short time that the material is kept in the coil, the temperature of the oil may be as high as 650 F. without great danger of injury to the oil. The oil has high velocity and turbulent flow through the coil so that rapid heat transfer to the oil takes place and local overheating is prevented. I

Driers such as those ordinarily used in oils may be added in the tank I and stirred into the oil and passed with it through the coil 1. Pigments may be added in a similar way. The driers or pigments become thoroughly mixed with the oil in'passing through the coil I even if they are not so mixed before the oil enters this coil. Air is excluded from the oil while it is being heated,

whether driers are present or not, andthe tendency of the oil to become yellow when used to make paints varnishes, etc., is decreased. Air is also excluded from the ofl while it is still hot in the tank 36.

When it is desired to remove volatile products I repeatedly, if necessary, until the desired amount of volatile matter has been removed, and the right proportion of vegetable oil necessary for making varnishes can then be added in the tank I and the mixture passed through the coil I and heated adequately in a few-minutes to impart the desired viscosity and specific gravity. The prior method of heating in kettles required many hours, often overheated or burned the oils and gums and contact with air atthe elevated temperatures often caused discoloration.

In using this invention, oil, containing a drier, which required boiling for four hours in a varnish kettle to increase its specific gravity from 0.9316 to 0.9512 and then required eleven hours to become dry, required only six minutes heating by this process to produce the same increase in speciflc gravity and it dried in six hours. The coil used was made of a steel pipe one-half inch incause volatile constituents to pass into vapor when the pressure is lowered, suddenly lowering side diameter and 320 it. long. The temperature to which the oil was increased was approximately 580 F.

In another run a mixture of linseed and Chinawood oil that would not dry in 24 hours and had a sp. gr. of .9465 was passed through the coil at such a rate that it was heated only six minutes without appreciable change in sp. gr. but the oil then dried in 19 hours. A sample of the same mixture passed through the coil twice under the same conditions had its specific gravity increased less than one-tenth of one per cent, but the drying time was reduced to 6 hours. It is very desirable inthe paint and. varnish industry to have oils that ill dry rapidly and still not have greatly increased viscosity and specific gravity. Heretofore, fast drying oils have necessarily been of high viscosity and high specific gravity.

By the present process, fish oils can be successfully treated so that they are bodied to the extent that make them suitable for use in the paint and varnish industries and at the same time the volatile constituents which impart an objectionable odor are removed. By heating such oils to temperatures of 580 F. to 600 F. while excluding contact with air they become polymerized or bodied to the desired extent. After the material has been heated in the-coil I and expanded in the chamber 36 it should be allowed to cool before being withdrawn through the outlet pipe 39 wherever there is danger of the material becoming injured by contact with air while it is hot. i

I claim:-

1. The process of treating a drying oil for making varnish and other products which comprises passing the oil through an elongated curved heated zone at a temperature suflicient to body said oil and at an elevated pressure sufiicient to limit volatilization of constituents while excluding air therefrom, suddenly releasing the pressure and withdrawing volatile products.

2. The process of treating a drying oil for making varnish and other products, which comprises, passing said 011 under pressure and out of contact with the air through a heated zone of such dimensions that the oil is substantially uniformly heated, raising the temperature of said oil in said zone sufiicient to body the oil and to said pressure and withdrawing said volatile constituents.

3. The process of treating a drying oil for making varnish and other products, which comprises, passing said oil through aiheated zone at an elevated pressure and out of contact with the air, maintaining suflicient velocity of said oil in said zone to cause the oil to be substantially uniformly heated, raising the temperature of said oil in said zone sufiicient to body the oil and to cause volatile constituents to pass into vapor when the pressure is released, suddenly releasing said pressure and withdrawing said volatile constituents.

4:. The process of treating a drying oil for making varnish and other products, which comprises, passing said oil at an elevated pressure and out of contact with the air through a heated zone of such dimensions that the oil is substantially uniformly heated, raising the temperature of said oil in said zone to approximately 580 R, suddenly releasing said pressure and withdrawing volatile products therefrom.

5. The process of treating a mixture of varnish adiuvants and a drying oil suitable for making varnish, which comprises, passing said mixture at an elevated pressure and out'of contact with the air through a heated zone of such dimensions that'the mixture is substantially uniformly heated, raising the temperature of said mixture in said-zone sufficient to body the oil and to cause volatile constituents thereof to pass into vapor when thepressure is released, suddenly releasing said pressure and withdrawing said volatile constituents.

6. The process of treating a mixture of gumand a drying oil suitable for varnish making, which comprises, passing the mixture through a heated zone at an elevated temperature and out of contact with the air, raising the temperature of said mixture in said zone suflicient to body the oil and to cause substantially all of the volatile constituents of said gum to pass into vapor when the pressure is suddenly released, suddenly releasing said pressure and withdrawing volatile constituents.

BENJAMIN H. THURMAN.

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