MULTI-SAMPLE CRUDE OIL GRAVITY TESTER

Abstract: A multi-sample crude oil gravity tester facilitating the simultaneous testing of multiple heavy crude oil samples of high viscosity in vertical hydrometer cylinders (11). The cylinders (11) are immersed in a constant temperature bath (16) complete with catch basins (23), (25) and drains (24) for all overflowed or spilled test fluids and a wiper tool (14) located at the top of each hydrometer cylinder (11) for the removal of excess crude oils from the hydrometer.

Description: Description MULTI-SAMPLE CRUDE OIL GRAVITY TESTER Technical Field The present invention relates to a multi-sample crude oil gravity tester, more particularly comprised of a series of vertical sample tubes or hydrometer cylinders in which the crude oil to be tested is placed. The hydrometer cylinders are immersed and heated by a mineral oil bath that brings the crude oil to the appropriate test temperatures. Hydrometers are then dropped into the hydro¬ meter cylinders and the specific gravities are read. One of the advantages of the invention is that it produces more accurate API gravities because there is no inter¬ mediate cooling of the outer oil sample surface as occurs in state of the art test methods. The test apparatus is particularly suitable for use in a laboratory or field environment and contains other features which make it especially desirable and preferable over present day work methods. These include wipers attached at the top of the vertical hydrometer cylinders which automatically remove excess crude oil from the hydrometers. Likewise, all areas where the possibility of spillage of the crude oil samples exists are connected to common drains which collect any such spilled liquids. This greatly in- creases the cleanliness and accuracy of the procedure. Background Art The price that a barrel of crude oil brings on the world market is determined by its API gravity. The formula for determining API gravity is well known in the trade and industry. A low API gravity indicates a heavy viscus crude oil and a high API gravity indicates a light less viscus crude oil. API gravity is directly related to the specific gravity of the crude oil being tested and is de¬ termined by floating a hydrometer in an oil sample. The method for measuring API gravity is set forth in ASTM D 1298-67 (API STANDARD 2547) . The method set forth in the standard calls for a constant temperature bath for use when the nature of the sample requires a test temper- ature much above or below room temperature. The standard, however, does not give specific instructions or specifi¬ cations concerning the constant temperature bath. It appears that no one in the industry has addressed themselves to the real problem of testing large numbers of heavy crude oils in the field or laboratory. It has become common industry practice to use a water bath to heat samples of crude oil to the desired temperature and then pour the samples of oil into some type of hydrometer cylinder to test the API gravity. This results in the immediate nullification of the ASTM procedure because the crude oil sample will begin an immediate cooling process at the sample/hydrometer cylinder interface. The previously cited standards require that the temperature between the cylinder and the surrounding medium should not change more than two degrees centigrade (five degrees Fahrenheit) when testing at temperaures much above or below room temperature and further states that a constant temperature bath may be necessary to avoid excessive temperature changes. Likewise, the testing of low gravity viscus crude oils is a messy and cumbersome procedure. These heavy crude oils cause the laboratory apparatus to. become hard to clean and as a result the test procedure itself is very undesirable leading to further inaccuracies and increased cost of glassware and other test apparatus. As will be shown, the present invention provides a laboratory apparatus with the capability of running simultaneous API gravity tests on a number of crude oil samples. The proposed laboratory apparatus provides for increased accuracy since it provides a circulating constant temperature bath that surrounds the crude oil sample being tested. It also provides for automatic wiping of the hydrometers as they are • removed from the samples. Disclosure of the Invention Accordingly, it is the object of the present invention to provide an apparatus for use in the laboratory or field for the simultaneous determination of API gravity on a number of crude oil samples. Another object of the invention is to provide an apparatus which increases the accuracy of crude oil gravity determinations for low gravity high viscosity crude oils. Another object of the invention is to provide an apparatus for use in the laboratory field which reduces the uncleanliness of gravity testing on low gravity crudes which has as a secondary benefit increased accuracy. Brief Description of the Drawings Figure 1 is a partially sectioned perspective view of the subject invention. Figure 2 is a front elevational view of the present invention. Figure 3 is a top elevational view of the present invention. Figure 4 is a sectioned side elevational view along section line AA. Figure 5 is a side elevational view of the present invention. Figure 6 is a top.elevational view of the hydrometer wiper located at the top of the hydrometer cylinders. Figure 7 is a side elevational view of the hydrometer wiper. Figure 8 ia a side elevational view of the wiper holder. Figure 9 is a top elevational view of the wiper holder. Best Mode for Carrying Out the Invention As seen in Figure 1, the apparatus which is the subject of this invention is generally designated as (10) and consists of a series of vertical uniform and parallel hydrometer cylinders (11) in which the crude oil sample being tested is placed. Each hydrometer cylinder (11) has at its base a valve (12) for draining of fluid. An intermediate valve (13) is located on each hydrometer cylinder at a position between the top and bottom of the tube. At the top of each hydrometer cylinder (11) is a hydrometer wiper (14) which removes excess oil from the hydrometer as it is removed from the test liquid. When not in use the hydrometer wiper (14) is placed in the hydro¬ meter wiper holder (15) . The hydrometer cylinders (11) are located in a constant temperature bath of mineral oil or other fluid designated generally as (16). Temperature gauge (20) indicates the temperature of the constant temperature bath which is circulated by means of the stirring mechanism (18) which is, in turn, driven by the stirring motor (19) . The level of the liquid in the constant temperature bath is indicated by the liquid level site glass (21) . Steam is circulated through the constant temperature bath through steam ports (22) to steam coils (32) . Also shown is the electrical element (31) , an alternate device for heating the constant temperature bath. To prevent the spillage of crude oil samples during the test procedure, a catch basin indicated generally as (23) surrounds the top of each hydrometer tube. The catch basin drains to the base (17) of the apparatus (10) by means of a drain (24) . The base (17) of the apparatus (10) provides for the catching of all extraneous or spilled fluids. It contains an expanded metal work surface (25) . Immediate- ly below the expanded metal work surface (25) is a rearward sloping plate (26) which carries extraneous fluids to the back and rear of the base (17) . The spilled or extraneous test fluids are kept warm and flowing by means of steam coils (27.) which are connected to steam ports (22) . Figure 2 is a front elevational view of the subject invention designated generally as 10. Again, Figure 2 shows the multiple hydrometer cylinders (11) with bottom valves (12) , intermediate valves (13) and hydrometer wipers (14) . .The hydrometer test cylinders (11) are immersed in a constant temperature bath designated generally as (16) which is circulated by stirring mechanism (18) driven by a stirring motor (19) . The temperature of the constant temperature bath is indi- cated by temperature gauge (20) the liquid level in the bath is indicated by the site glass (21) . Heat is pro¬ vided to the constant temperature bath by means of steam introduced through steam coils (32) , or electricity. Steam is introduced through steam ports (22) . The steam introduced heats the constant temperature bath (16) and the base (17) of the apparatus (10) where extraneous or spilled fluids collect. An alternative means of heating is by an electrical element (31) attached to the controller (33) . Crude oil which is spilled during the sampling procedure collects in drain pan (23) and is carried to the .bottom of the base (17) of the apparatus (10) by means of the vertical drain (24) . Again when the hydrometer wipers (14) are not being used they are placed in the hydrometer wiper Oϊ.-rl holder (15). Figure 3 is a top elevational view of the apparatus designated generally as (10) . Visible are the vertical hydrometer cylinders (11) with hydrometer wipers (14) in place and the wiper holder (15) . The temperature gauge (20) and site glass (21) are seen. Also shown are the steam ports (22) for the introduction of steam into the steam coils (32) and (27) . The alternative method of electrical heating is shown by the electrical element (31) and controller (33) . The expanded metal work surface (25) is at the base (17) of the apparatus (10) and catches any extraneous or spilled fluids. Steam coils (27) located in the base keep the heavy crude oils warm and flowing. Figure 4 is a cross sectional side elevational view taken along section lines A-A shown in Figure 2. Figure 4 shows the- apparatus generally designated as (10) with the constant temperature bath generally designated as (16) . The bath is circulated by means of stirring mechanism (18) driven by stirring motor (19) . The hydrometer cylinders (11) are placed vertically and align¬ ed in the constant temperature bath (16) . Each hydrometer cylinder has at its base a valve (12) for drainage and an intermediate valve (13) for sampling. At the top of the hydrometer cylinder (11) is the hydrometer wiper (14). When the hydrometer wiper (14) is not in use, it is placed in the hydrometer wiper holder (15) . Extraneous crude oils which are spilled during the test procedure and which eminate from the top of the hydro- meter test cylinders (11) or the hydrometer wiper holder (15) are collected in catch basin (23) . These fluids are carried by means of drain (24) to the base (17) of the apparatus (10) . The temperature of the constant temperature bath is indicated by the temperature gauge (20) . The constant temperature bath is heated by means of steam coils (32) or an alternatively electrical element (31) . Extraneous or spilled crude oils which are carried to the base (17) of the apparatus (10) travel through the expanded metal work surface (25) contact the rearward sloping plate (26) and are collected at the bottom and rear of the apparatus. Steam coils (27) keep spilled liquids warm and flowing. Figure 5 is a side elevational view showing the general apparatus (10) . The hydrometer cylinders (11) are shown protruding from the liquid bath; each having its own base valve (12) and intermediate valve (13) . The wiper holder (15) is seen above apparatus (10) in front of the stirring motor (19) . In addition to the temper¬ ature gauge (20) , the ite glass (21) is also visible. The drain (24) extends vertically downward to the expanded metal work surface ' (25) on base (17) . The steam port (22) is shown as it attaches to steam coils (27) and (32) . The electrical controller (33) is also shown. Figure 6 shows a top elevational view of the hydrometer wiper (14) . The wiper (14) is comprised of a circular metal holder (41) with a concentric internally mounted pliable element (42) . As hydrometer tubes are removed from the hydrometer cylinders, excess crude oils are removed from the hydrometers by means of pressure applied by the pliable element. Figure 7 shows a side elevational view of the hydrometer wiper (14) with circular mounting (41) and pliable element (42) . Side port (43) allows for the locking of the wiper on the hydrometer cylinder. Figure 8 shows a side elevational view of the wiper holder (15) with slot (51) which allows the draining of collected fluids. Figure 9 is a top elevational view of the wiper holder (15).

Claims: Claims 1. A multi-sample crude oil gravity tester comprising: a. A series of parallel vertical cylinders in which crude oil samples are placed. b. A constant temperature bath in which the vertical parallel cylinders are placed; and c. A means for heating the constant temperature bath and keeping it at a uniform temperature. d. A catch basin at the top of and surrounding the vertical cylinders to collect overflow from the vertical cylinders. e. A base which collects all spilled or extraneous fluids. f. Means to transfer oil from the catch basin to the base. g. A means for heating the base for the purpose of reducing the viscosity of the spilled crude oil. 2. The multi-sample crude oil gravity tester in claim 1 where in each parallel vertical cylinder has at its base a valve for the evacuating of the cylinder, an intermediately placed valve for sampling the test fluid, and a wiper device at the top of the vertical cylinder for the removal of excess crude oils from the hydrometer. O

Inventors: BENTLEY JAMES K, TONTI NICHOLAS, YOUNG MICHAEL J, BENTLEY, JAMES, K., TONTI, NICHOLAS, YOUNG, MICHAEL, J.
Applicants: BENTLEY JAMES K, TONTI NICHOLAS, YOUNG MICHAEL J, BENTLEY, JAMES, K., TONTI, NICHOLAS, YOUNG, MICHAEL, J.
Application year: 1982
Main classification: G01N9
IPC codes: G01N9