US2902857A

US2902857A - Analytical test apparatus

Info

Publication number: US2902857A
Application number: US590215A
Authority: US
Inventors: Sayers Winston; Don J Wangelin
Original assignee: Pure Oil Co
Current assignee: Pure Oil Co
Priority date: 1956-06-08
Filing date: 1956-06-08
Publication date: 1959-09-08
Anticipated expiration: 1976-09-08

Description

Sept. 8, 1959 Filed June 8, 1956 Ila.

FIGJ

w. SAYERS ETAL 3 Sheets-Sheet 1 IIb W/KQ

ATTORNEY Sept. 8, 1959 w. SAYERS I ET AL ANALYTICAL TEST APPARATUS 3 Sheets-Sheet 2 Fi led June a, 1956 Sept. 8, 1959 w. SAYERS ETAL ANALYTICAL TEST APPARATUS I5 Sheets-Sheet 3 Filed June 8, 1956 FIG.

Ion

FIG.5

INVENTORS WINSTON SA YE RS BY DON .J. WANGELIN gM/MA ATTORNEY United States Patent ANALYTICAL TEST APPARATUS Winston Sayers, Libertyville, and Don J. Wangelin, Barrington, Ill., assignors to The Pure Oil Company, Chlcago, 111., a corporation of Ohio Application June 8, 1956, Serial No. 590,215

Claims. (Cl. 73-53) This invention relates to an apparatus for determining the aniline point and mixed aniline point of petroleum products and hydrocarbon solvents.

Because of the variety of applications for petroleum products it becomes necessary to employ qualitative or semi-quantitative analytical techniques to evaluate the adaptability of a petroleum product for a particular use. Petroleum fractions having the same or similar boiling ranges will vary in hydrocarbon composition depending upon the source of the crude petroleum oil from which the fractions were obtained. The peculiar properties attributable to the various series of hydrocarbons such as parafiins, olefins, naphthenes, and aromatics, require that test procedures be established for qualitatively and semi-quantitatively determining the content of these hydrocarbon series in various petroleum products. For example, aromatic hydrocarbons have superior solvency properties, but when present in distillates such as fuel oil, kerosine, diesel fuel, and the like, they tend to cause these products to burn with a smoky flame. To determine the presence of aromatic hydrocarbons in petroleum products there has been established the so-called aniline point test (ASTM Designation: D611-55T). According to this test:

Specified volumes of aniline and sample, or aniline and sample plus diluent, are placed in a tube and mixed mechanically. The mixture is heated at a controlled rate until the two phases become miscible. The mixture is then cooled at a controlled rate and the temperature at which the two phases separate is recorded as the aniline point or mixed aniline point.

To effect proper agitation of the test mixture, a specific stirrer design is used. This stirrer is fabricated from a length of #14 B and S gage soft iron Wire. At one end is formed perpendicularly to the shank section, a ring having a diameter of about 19 mm. The shank section is approximately 200 mm. long, terminating in a right angle bend to provide a handle for manual manipulation of the stirrer.

The test specifications permit the use of any suitable mechanical device for operating the stirrer.

It is therefore an object of this invention to provide an apparatus for aniline point test which employs an effective mechanical stirrer, thereby permitting the aniline point test to be carried out in a facile manner with exccllent repeatability and reproducibility. It is another object of this invention to permit the simultaneous determination of the aniline points of a plurality of samples.

These and other objects of this invention will become apparent from the following detailed description of this invention.

Figure 1 is an isometric sketch of the unitary assembly in an operating condition.

Figure 2 is a front view of the stirrer assembly of the apparatus removed from the panel.

Figure .3 is a side view of the panel assembly.

" Figures 4 and 5 are bottom and rear views, respec- "2 tively, of the cross-bar element to which the stirrer elements are affixed.

Figures 6 and 7 are front and side views, respectively, of the drive which operates the cross-bar element.

Figure 8 is a sketch of an alternative assembly employing a tubular standard.

With reference to the drawing, it is seen that the assembly is mounted on a suitable standard such as panel 10. This standard is provided with support means, e.g., panel legs 11a and 11b, which retain it in an upright position. Mounted on the standard at an elevated position is electric motor 12 which can be retained in position by a platform or the like, such as motor mounting bracket 13. Attached to the rotating shaft 14 of motor 12 is cam-drive 15. Eccentrically positioned on the face of the drive is cam 16 which registers with cam groove 17 provided in the face of cam-follower crossarm 18. It is to be noted that the specifications of the aniline point test, cited supra, advise that a 2-inch stroke be employed in stirring the sample. Accordingly, cam 16 is mounted on the face of cam drive 15 at a radius selected to provide a stroke of about /3 to 2% inches for the stirrer element.

Guide-rod 19 is attached to cross-bar 18 in fixed relation therewith. This fixed relationship can be retained by employing a means, such as set-screw 25 as illustrated, which will permit periodic adjustments, or by a more permanent technique, e.g., welding, brazing, or the like. The path of guide-rod 19 is controlled by

guides

26 and 27 which are mounted on upright standard 10 in a manner such that a vertical reciprocating motion is given to cross-arm 18. The cross-arm 18 is provided with a plurality of fastening means, such as threaded

fasteners

30a and 30b, for attaching stirrer elements 311: and 31b thereto. It is preferred that a pivotal connection between the stirrer element and the cross-arm be employed; however, a rigid mounting can be used, if desired. To position the sample so that it can be effectively stirred,

clamps

32a and 32b are provided. It is preferred that these clamps be laterally adjustable. This can be effected by means of threaded arms 33a and 33b in cooperation with threaded fastener 34a and locking means 35a. The arms of

clamps

32a and 32b

grasp sample holders

37a and 37b. These sample holders, in accordance with the provisions of the aniline point test, cited supra, comprises jacketed test tubes. The test tube is approximately 25 mm. in diameter and mm. in length, and the jacket is approximately 37 to 42 mm. in diameter and mm. in length, both being made of heat-resistant glass. The

sample holders

37a and 37b can be fabricated from separate units which are held in spaced relationship by a suitable annular closure such as cork or rubber stopper, or in the form of a unitary element by appropriately welding the lips of the jacket and test tube to a web portion which holds the respective units in the required coaxial relationship as shown. This eliminates the necessity for the annular sealing cork and provides an easily handled and cleanable assembly. For accurate, reproducible results, contamination must be avoided as far as possible, and elimination of the cork ring-seal reduces the chances for any contamination of the materials under test. To aid in control of heating and cooling rates, the jacketed tube is provided'with inlet 41a and outlet 41b through which a heat exchange medium, such as heated or cooled air, or other gas or liquid, may be introduced and withdrawn at any desired rate to provide complete control over the critical heating and cooling rates. The mouths of the test tubes are covered with closure means 42a and 42b in which are disposed first openings for ASTM aniline point thermometers 43a and 43b and second openings in which are placed short sleeves 44a and 44b which function-as 3 guides for the stirrers. When a stirrer element is fitted in place, the ring section of the stirrer circumscribes the thermometer.

Although several procedures are available for deter- .colored samples, not darker than No. 8 ASTM color (ASTM Method 13-155) Inemploying the instant invent-ion for determining aniline point or mixed aniline point, 10 ml. of aniline and 10 ml. of a dried sample of petroleum product are placed in

sample holder

37a or 37b. The stirrer element and thermometer are properly arranged in the tube, and closure 42 is fitted in the mouth of the test tube. The thermometer is centered in the sample holder so that the immersion mark is at the liquid level, making sure that the bulb does not touch the side of the tube. The stirrers 31 are then attached to threaded fasteners 30 on cross-arm 18. Air lines 53a and 5311 are connected to the inlets of the test vessel air jackets, and the air flow is adjusted to a desired rate. Suitable heating means such as burners 50a and Stlb are then started, and motor 12 is energized by power from a suitable source controlled by switch 54. The motor, 12, cooperating with drive-wheel 15 and cross-arm 18, moves stirirer element 31 in reciprocating, uniform, vertical paths within the aniline-sample mixture. The heaters, 50a and are adjusted to give the desired rate of temperature rise and, when complete miscibility has been attained, they are turned off and the mixture is allowed porting the various elements of this invention. Such an expedient is shown in Figure 8. The motor which was employed in the preferred embodiment was a 140 rpm, 110 volt, 60 cycle motor; however, other types of fixed or variable speed motors can be employed. It may also be preferred to substitute a crank arm for the disc-like cam drive employed in the preferred embodiment. Regardless of the configuration of the cam-drive, counterweight 52 should be mounted on the drive opposite the cam to minimize vibration of the apparatus during its operation. Friction between the cam and cam groove can also be reduced by employing a rotatable element, such as a ball or roller bearing, as cam element 16. The cross-arm 18 is also susceptible to variations in design. While the illustrated design shows provisions for carrying out two determinations simultaneously, the length of the cross-arm can be varied to permit additional samples to be tested. In addition, the positioning and number or" the guide means for controlling the reciprocative motion of the cross-arm can be altered. For example, a single guide can be used, the guide means can be mounted above or below the cross-arm in place of the upper and lower mounting used in the preferred embodiment, etc. Normally, cross-arm 18 will be mounted at right angles to guide-rod 19. This does not preclude a non-pe1pendicular joining of the guide-rod and cross-arm, but in this instance it will be necessary to adjust the positioning of the specimen holder to provide for a uniform length of stroke of each stirrer element employed. It is preferred that substantially vertical and horizontal relationship be maintained in constructing and assembling the apparatus of this invention. Should deviations in design be considered necessary, the following criteria must be employed.

(a) Positioning of cam on cam-drive to provide a stirrer stroke of 1 to 3% inches. This can be made to permit adjustment of the stroke as opposed to the fixed stroke illustrated.

(b) Maintaining parallel relationship between the longitudinal axes of the guide ll'Od, sample holder and stirrer path.

(0) Conformance with apparatus requirements of aniline point test method I (ASTM D-6ll).

Although the foregoing description of this invention is directed to a multiple stirrer apparatus for use in conducting the aniline point test, it is apparent that it will have other analytical applications such as freezing point determinations, or the like which require a gentle, uniform agitation while carrying out the test work. In these applications, various stirrer designs can be used. Accordingly, we claim as our invention:

1. For determining the aniline point in accordance with method I, ASTM designation D6l155T, of petroleum products, an apparatus which comprises an upright standard, an electrical motor mounted on said standard, a cam-drive rotated by said motor, a cam eccentrically mounted on said cam-drive, a cross-arm reciprocatively mounted on said standard, said cross-arm having a guide rod transversely attached thereto and a longitudinal groove registering with said cam, guide means mounted on said standard and slidably engaging said guide rod to maintain a uniform, straight line, reciprocative motion for said cross-arm, a plurality of sample holders each comprising a jacketed test tube having an inlet means and an outlet means in the jacket section, means for clamping said sample holders to said standard, a stirrer element fitted in each of said sample holders, each of said stirrers comprising a shank portion, a ring section extending at a right angle to said shank portion at the terminal end disposed in said sample holder, the other terminal end of said stirrer being afiixed to said reciprocatively mounted cross-arm spaced from said guide rod, the longitudinal axis of said sample holders and the reciprocative path of the stirrer elements mounted therein being substantially coextensive, an ASTM aniline point thermometer disposed in said sample holder, said thermometer being circumscribed by the ring section of said stirrer element, and a closure means for said sample holder, said closure means having a first opening for retaining said thermometer in said sample holder, and a second opening having fitted therein a guide means cooperating with the shank portion of said stirrer element.

2. For determining the aniline point in accordance with method I, ASTM designation D-6l1-65-T of petroleum products, an apparatus which comprises an upright panel contmning an opening, an electrical motor mounted on said panel adjacent said opening, a camdrive rotated by said motordisposed within said opening, the plane of rotation of said cam-drive being substantially coplanar with the plane of said panel, a cam eccentrically mounted on said cam-drive, a cross-arm reciprocatively mounted on said panel, said cross-arm having a guide rod transversely attached thereto and a longitudinal groove registering with said cam, guide means mounted on said panel and slidably engaging said guide rod to maintain a uniform, straight line, reciprocative motion for said cross arm, said guide means comprising pillow blocks, a plurality of sample holders, each comprising a jacketed test tube having inlet and outlet means in the jacket section, means for clamping said sample holders to said panel, a stirrer element fitted in each of said sample holders, each of said stirrers comprising a shank portion, a ring section extending at a right angle of said shank portion at the terminal end disposed in said sample holder, the other terminal end of said stirrer being afiixed to said reciprocatively mounted cross-armsp-aced from said guide rod, the longitudinal axis of said sample holders and the stirrer elements mounted therein being substantially coextensive, an ASTM aniline point thermometer disposed in each of said sample holders, said thermometer being circumscribed by the ring section of said stirrer element, and a closure means for said sample holder having a first opening for retaining said thermometer in said sample holder, and a second opening having fitted therein a guide means for cooperating with the shank portion of said stirrer element.

3. For determining the aniline point inaccordance with method I, ASTM designation D-611-55-T of petroleum products, an apparatus which comprises a vertically upright panel containing a circular opening symmetrical about the vertical axis of said panel, an electrical motor having a rotatable shaft mounted on said panel, the axis of said shaft being substantially perpendicular to the center of said opening, a disc-like, counter balanced, camdnive disposed within the said opening and rotated by said shaft, a cam eccentrically mounted on the face of said drive cam, the face of said drive cam and the face of said panel being substantially coplanar, a horizontal cross-arm reciprocatively mounted on said panel, said cross-aim having a guide rod perpendicularly and sym metrically attached thereto adjacent the vertical axis of said cross-arm and in one vertical face thereof, a longitudinal groove registering with said cam guide, means comprising pillow blocks mounted on said panel in alignment with the vertical axis thereof and slidably engaging said guide-rod to maintain a uniform, vertical, straightline reeiprocative motion, a plurality of sample holders each comprising a jacketed test tube having inlet and outlet means in the jacket portion, means for clamping each of said sample holders to said panel, a stirrer element fitted in each of said sample holders, each of said stirrers comprising a shank portion, a ring section extending in a right angle to said shank portion at the terminal end of said sample holder, the other terminal end of said stirrer being afiixed to said reciprocatively mounted cross-arm and spaced from said guide rod, an ASTM aniline point thermometer disposed in each of said sample holders, said thermometers being circumscribed by the ring section of said stirrer element, and a closure means for each of said sample holders, said closure means having a first opening for retaining said thermometer in said sample holder, and a second opening having fitted therein a guide means cooperating with the shank portion of said stirrer elements.

4. Apparatus in accordance with claim 3 in which said sample holder comprises a test tube coaxially disposed an outer jacket to provide an enclosed volume surrounding the walls of said test tube, the coaxial relationship between said tube and jacket being maintained by a transverse Wall integrally connected to the lips of said tube and said jacket and an inlet means, and an outlet means, mounted in the Wall of said jacket whereby a fluid heat transfer medium can be circulated through said enclosed volume. v i

5. For determining the aniline point of petroleum products, an apparatus which comprises an upright standard, an electrical motor mounted on said standard, an eccentric cam operably supported by said standard and driven by said motor, a cross-arm reciprocatively mounted on said standard, said cross-arm having a guide-rod transversely attached thereto, and a longitudinal groove registering with said cam, guide means mounted on said standard and slidably engaging said guide-rod to maintain a uniform, straight-line, reciprocative motion for said cross-arm, a plurality of sample holders each comprising a jacketed test tube having an inlet means and an outlet means in the jacket section, means for clamping said sample holders to said standard, a stirrer element fitted in each of said sample holders, each of said stirrers comprising a shank and a reciprocable agitator means attached to that end of the shank disposed within said sample holder, the other end of said shank being affixed to said reciprocatively mounted cross-arm, the longitudinal axis of said sample holders and the reciprocative path of the stirrer elements disposed therein being substantially coextensive, a thermometer disposed in said sample holder, and a closure means for said sample holder, said closure means having a first opening for retaining said thermometer in said sample holder, and a second opening having fitted therein a guide means cooperating With the shank portion of said stirrer element.

References Cited in the file of this patent UNITED STATES PATENTS 63,515 Hawk Apr. 2, 1867 1,443,537 Hortvet Jan. 30, 1923 2,068,976 Dillon Jan. 27, 1937 2,252,750 Basch Aug. 19, 1941 2,349,482 Welty May 23, 1944 2,437,194 Harrington Mar. 2, 1948 2,604,392 Brown July 22, 1952 OTHER REFERENCES Standard Methods of Testing Petroleum and its Products, page 23, method A, 1955,