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Gardner Standard Bubble Viscometers

Sets of Filled Standard Tubes From A-5 to Z-10 series

Meets ASTM D1545 and Other Specificaations

	Set of 20 bubble tube standards designated A thru T with 2 empty tubes (Grade A, Class G) and directions for use, complete in storage case. Weight: 3 lbs net; 7 lbs shipping weight.
Item Number Item VI-VG-9100 Gardner Bubble Viscometer Set A thru T

Item Number Tube Stokes VI-VG-9101 A 0.50 VI-VG-9102 B 0.65 VI-VG-9103 C 0.85 VI-VG-9104 D 1.00 VI-VG-9105 E 1.25 VI-VG-9106 F 1.40 VI-VG-9107 G 1.65 VI-VG-9108 H 2.00 VI-VG-9109 I 2.25 VI-VG-9110 J 2.50

Item Number Tube Approximate Stokes VI-VG-9111 K 2.80 VI-VG-9112 L 3.00 VI-VG-9113 M 3.00 VI-VG-9114 N 3.40 VI-VG-9115 O 3.70 VI-VG-9116 P 4.00 VI-VG-9117 Q 4.40 VI-VG-9118 R 4.70 VI-VG-9119 S 5.00 VI-VG-9120 T 5.50

Item Number	Item
VI-VG-9000	Gardner Bubble Viscometers A5 thru A1

Set of 5 bubble tube standards designated A5 thru A1, with 2 empty tubes (Grade A, Class G) and directions for use, complete in storage case. Weight: 1 1/2 lbs net; 5 lbs shipping weight.

Single Standard Bubble Tubes A5 - A1: Item Number Tube Stokes VI-VG-9001 A5 0.005 VI-VG-9002 A4 0.062 VI-VG-9003 A3 0.140 VI-VG-9004 A2 0.220 VI-VG-9005 A1 0.320

Item Number	Item
VI-VG-9200	Gardner Bubble Viscometer Set, U thru Z6

Set of 12 bubble tube standards designated U thru Z6, with 2 empty tubes (Grade A, Class G) and directions for use. Complete in case. Weight: 2 1/2 lbs net; 7 lbs shipping weight.

Single Standard Bubble Tubes U thru Z6 Item Number Tube Approximate Stokes VI-VG-9201 U 6.27 VI-VG-9202 V 8.84 VI-VG-9203 W 10.70 VI-VG-9204 X 12.90 VI-VG-9205 Y 17.60 VI-VG-9206 Z 22.00 VI-VG-9207 Z1 27.00 VI-VG-9208 Z2 36.20 VI-VG-9209 Z3 46.30 VI-VG-9210 Z4 63.40 VI-VG-9211 Z5 98.50 VI-VG-9212 Z6 148.00

Item Number	Item
VI-VG-9250	Gardner Bubble Viscometer Set, Z7 thru Z10

Set of 4 bubble tube standards designated Z7 thru Z10 with 2 empty tubes (Grade A, Class G) and directions for use, complete in storage case. Weight: 1 1/2 lbs net; 5 lbs shipping weight.

Single Bubble Viscometer Tubes, Z7 thru Z10 Item Number Tube Approximate Stokes VI-VG-9251 Z7 388 VI-VG-9252 Z8 590 VI-VG-9253 Z9 855 VI-VG-9254 Z10 1066

Gardner Empty Viscosity Tubes

Proceedure for Use Knowing the approximate viscosity, pick four standard tubes closest in viscosity to your sample Fill the sample tube with liquid, insert a cork, and then using the tube holder insert the four lettered tubes and the sample tube into the holder. Turn over the holder and visually compare what letter best matches the rise time of the bubble in the sample The rise time in seconds of the sealed tubes and samples can also be determined using a basic timer Please be aware of the following accuracies when performing the test: Temperature control: 1°C =  10% error Verticality control: 5° slant =  10% error Tube I.D. control: 0.1mm =      2% error

Item Number	Item
VI-730391	Empty Tubes, Grade A, Class G, 144/pkg w/corks, 10.65mm
VI-730392	Empty Tubes, Grade B, Class V, 144/pkg w/corks, 10.75mm (economy)
VI-730551	Empty Tubes, Grade N, 144/pkg w/corks & Time Test ASTM D 1545
VI-44106/GR	Empty Tube, Grade A, Cargill
VI-730383	Corks, 150/pkg

Hand-Held Tube Holder, 5 Tube

Sturdy metal frame with plastic handle holding 5 tubes in one row by means of spring clips. Flat ends allow holder to be set in vertical position in water bath or on table. Comes without tubes. Weights: 1/2 lbs net; 2 lbs shipping weight.

Item Number	Item
VI-VG-7420	Tube Holder

Cargille Empty Viscosity Tubes

For Measuring Viscosity By The Air Bubble Rise Method
Meets ASTM D 1545

Introduction Rheology is a branch of science dealing with the deformation and fl ow of materials which includes the subject of viscosity. Viscosity is a measurement of internal friction, or resistance, to fl ow by external forces. Viscosity is the ratio of shear force to shear rate (the slope of the curves in Fig. 1a) expressed by: The viscosity of many materials depends on shear rate and is classified accordingly, Fig 1b. Viscosity is expressed as Absolute, n, and Kinematic, v. Absolute viscosity is determined by measuring the shear force required to produce a given shear rate and is independent of the density of the liquid. Kinematic viscosity is measured by the time required for a given volume of liquid to flow through a capillary or restriction. It is related to flow caused by the hydrostatic head of the liquid and therefore strongly dependent on density.

The relationship between Absolute and Kinematic viscosity is given by the following, where p is density:

v = n/p

One of the simplest methods for determining Kinematic viscosity is by the rising bubble technique employing matched viscosity tubes. The method is visual, convenient, rapid and easily learned by technical and non-technical personnel.

Rising Bubble Technique, Principle

The time required for an air bubble in a liquid to rise is directly proportional to its viscosity. Bubble rise rates vary with the inside diameters of viscosity tubes; therefore, the tubes must be precision matched to a tolerance that will keep bubble rise rate variations below the level of visual detection. Variations in viscosity readings or comparisons are visually imperceptible from viscosity tubes with inside diameter tolerances closer than ±0.025mm. Any variations in readings are attributed to differences in viscosities.

Viscosity is determined by either measuring the time an air bubble takes to pass between two specifically spaced marks on viscosity tubes, or by comparison to the bubble rate rise of calibrated viscosity standards. The accuracy of the method is therefore a function of precision matching of tube bores and identical score heights, which are measured from the center outside bottom.

Other factors, such as uniformity of temperature and verticality of tubes, influence timed bubble travel and controlled laboratory techniques are essential for precise results. For example, a variation in temperature of 0.1°C will cause a 1% variation in the timed bubble travel, and a one radius departure from tube verticality may introduce a 10% error in the timed bubble travel.

Procedure For Using Cargille Viscosity Tubes

A viscosity tube is filled to the 100mm level score with the material to be tested. A cork is inserted to the 108mm score which provides and fixes a uniform air bubble. The sample, and standard if used, is placed in a suitable rack and immersed in a water bath until a uniform temperature of 25°C (77°F) is attained. If viscosity determinations are performed by referral to comparison samples of known viscosities or precisely calibrated standards, then they, too, should be at the same temperature as the samples. Viscosity is determined by one of two methods:

Comparison Method
The bubble rate rise of the samples is compared to samples of known viscosities or calibrated standards contained in tubes of the same dimensions. The rack containing the samples and standards is removed from the water bath, held vertically to stabilize the air bubbles and quickly inverted maintaining verticality.

A comparison of air bubble speed of the samples to the standards permits estimation of viscosity; the faster the rate of bubble rise, the lower the viscosity. The user may prepare viscosity standards or employ Gardner Viscosity Standards.

Time-Method (ASTM D 1545)
TimeTest Tubes are required to determine viscosity by the Timed-Method. The length of time, in seconds, required for an air bubble to pass from the 27mm to 100mm score mark, a distance of 73mm, is approximately equal to the viscosity of the liquid in “Stoke” units; alternatively, viscosity may be expressed in “Bubble Seconds.” It is important to note that the position of the air bubble in relation to the 27mm score should be similar at the end of the test on the 100mm score.

Viscosity Tube Selection Guide

Cargille Viscosity Tubes are divided into three Classes as determined by precision sorting in accordance with bore size, number of score marks and contemplated method of use for bubble rise testing, Fig. 2. The numbers assigned refer to the bore size, which is expressed in mm.

Time-Test Viscosity Tubes, 10.65mm
Time-Test Viscosity Tubes are frequently referred to as ASTM D-1545 Tubes, which originated from the adopted standard method of test for viscosity as described in ASTM D-1545 issued by the American Society for Testing and Materials. Time-Test Tubes are scored in three places: Fig. 3a: 27mm, 100mm and 108mm. The score mark at 27mm is used for a 73mm timed travel. Time-Test Viscosity Tubes are also subjected to additional testing procedures to ascertain the 10.65mm bore which is very critical for precision measuring.

Class “G-10.65” and “V-10.75” Tubes
Class “G-10.65” and “V-10.75” Viscosity Tubes are used principally for direct comparisons to Gardner Viscosity Standards. Both Classes of tubes are inscribed at the 100mm and 108mm lengths, Fig. 3b. For bubble rate rise comparisons to Gardner Viscosity Standards, the following equivalency chart is provided:

Classification of Cargille Viscosity Tubes

Viscosity Tube Specifications

Dimensions Cargille Viscosity Tubes are manufactured to the closest possible tolerances and then precisely measured for final selection. Length 114mm ±2mm Wall Thickness .0.65mm Tolerance, I.D. ±0.025mm Composition Soda-lime glass, flat bottom Score Height Tolerance ±0.5mm NOTE: Inside diameter tolerance closer than ±0.025mm is unnecessary since variations in viscosity readings or comparisons would be imperceptible. Score Marks All Cargille Viscosity Tubes are permanently inscribed with two score marks, at 100mm and 108mm heights (Fig 3b) with the exception of Time-Test Viscosity Tubes, which have an additional score at 27mm (Fig. 3a). In compliance with ASTM D 1545, all score marks are measured from the center outside bottom of the tubes. The score mark at 100mm represents the filling level and the 108mm score is used to fi x the size of the air bubble in the tube by inserting a cork to this mark. The 27mm and 100mm scores on Time-Test Viscosity Tubes are used to time the bubble rise. Specification References: American Oil Chemists Society (AOCS) Method Ka6-63 American Society For Testing and Materials D1131 53 (1975), D1545 89 D1725 62 (1970) Federal Test Method Standard (FTMS) Method 4271	Fig 3a
	Fig 3b

Viscosity Tube Accessories

Rough Short Tubes   Tubes unsuitable for viscosity applications are separated, sorted, matched and grouped into two ranges according to tube bore size. Although these tubes are not precesion matched or scored, they are adquately matched in bore size for diversified use in general industrial and laboratory procedures. Rough Sort Tubes-Low.....Range 10.50-10.75mm Rough Sort Tubes-High....Range 10.75-11.00m		Corks High quality, short length corks, properly fit viscosity tubes so that the small end is in firm contact with inside of tubes to prevent small extraneous bubbles from interfering with timed bubble movement.
Viscosity Tube Holder All stainless steel construction, holds up to 10 viscosity tubes by convenient spring loading design. Samples and standards may be concurrently immersed in water bath, removed and held vertically for bubble rate rise comparison.
Viscosity Tube Holder Box A durable, compact, solid, fi breboard Sample Storage Box with attractive dark green, moisture and abrasive resistant exterior covering holds up to 100 viscosity tubes in partitioned compartments. The compartments are arranged 5X20 and are alpha-numerically indexed for rapidly locating stored viscosity samples. Boxes are supplied with separate, correspondingly-numbered index charts for recording pertinent sample information, and an exterior card in a polished brass card holder for easily identifying the general contents of the sample storage box.
Shell Vials Tubes exhibiting bore sizes exceeding Viscosity, Color and Rough Sort Tube specifications are availabe for innumerable laboratory applications where inside dimensional tolerance is critical. Dimensions 114mm long, approximate 12mm O.D., 0.65mm wall thickness.		Color Tubes Critical color or turbidity comparisons are frequently affected by variations in the light path of the liquid sample. To minimize this “visual diluting” effect, tubes are availlable with matched bore sizes to ±0.05mm to insure replicate volume comparisons under similar light path conditions. Dimensions 114mm long , 10.80mm I.D., 0.65mm wall thickness.

Item Number	Item
VI-44154/GR	Time Test (ASTM D-1545) Grade N w/ corks
VI-44106/GR	Class “G-10.65”mm dia Grade A w/ corks
VI-44107/GR	Class “V-10.75”mm dia Grade B w/ corks
Accessories
VI-44200 or 44250/GR	Rough Sort Tubes (Specify High or Low Range)
VI-44350/GR	Color Tubes
VI-36134/GR	Shell Vials
VI-36132	Viscosity Tube Sample Storage box (Model CK-3)---(Ea.)
VI-44010	“10” Viscosity Tube Holder
VI-44004	Corks (for Viscosity Tubes), 150 corks per package---(Pkg)
TH-0482	Gardco STIRstick, 20-30°C, 0.1°C increments

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