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The use of programmable liquid baths for ASTM D2983 has been allowed since the first development of the test if the cooling profile meets the specifications of Annex A2 of the method.
The Lawler liquid baths are programmed such that the sample cooling rate equals the cooling rate experienced by a sample when immersed in the constant low temperature air chamber. The bath can also be programmed to cool at a rate of 1°C per minute from ambient to as low as -55°C as per CEC-L-18A, ISO 9262, and IP 267 for the measurement of European low temperature Brookfield viscosity.
Operating temperature range of the programmable liquid baths is +20° to -55°C. Temperature control is within ±0.1°C. Windows based PC proprietary software is capable of controlling two baths simultaneously. This allows operating baths at two independent temperatures with independent start, stop, and duration times.
The bath is an unsilvered Dewar jar holding about 3 liters of bath medium. The illuminated jar allows full visibility of the test samples to facilitate the proper position of the spindle bead immersion level.
The turntable holds 10 test samples. After the 16 hours conditioning time, the turntable is manually rotated until the proper test cell is under the viscometer. The spindle is connected while the sample is still in the liquid bath. This allows the measurement of viscosity without removing the sample from the temperature controlled environment. Far superior viscosity data repeatability is obtained using this procedure as opposed to the air chamber procedure.
Duplicate samples at -40°C were measured in a Model 76 Liquid Programmable Bath. Of the 56 samples, the average variability between the duplicate samples was ±1.13% of mean. This compares very favorably to the method’s stated precision of 11.8%. The key factor in this improved precision is the superior temperature control of the sample as its viscosity is being measured.
Model LB-76 Programmable Liquid Bath is a bench top model has a single bath with 10 sample capacity. A Windows based PC is required (not supplied). The bath is supplied with an integral leveling viscometer support rod.
Model LB-76-2 is a bench top model and is identical to Model LB-76 but with two independently controlled baths, each with 10 sample capacity. This allows two simultaneous tests at different temperatures, and independent start and/or stop times.
Model LB-76-2G is a identical to Model LB-76-2 but configured as a floor model.
LB-76
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1
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10
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-55ºC
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23x24x27
(58x61x69)
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300/28
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LB-76-2
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2
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20
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-55ºC
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27x34x25
(68x85x63)
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440/32
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LB-76-2G
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2
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20
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-55ºC
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27x34x25
(68x85x63)
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440/32
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KVS-1
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Table for Model LB-76
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LM-PC
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Lawler supplied computer configured with software. Specify PC or laptop |
UR-PC
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Customer supplied computer configured by Lawler |
PCD
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Drawer for laptop PC or keyboard |
KVS-1
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Floor stand for Model LB-76 |
KVS-2
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Floor stand for Model LB-76-2 |
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92-10
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Dry block bath for sample preconditioning, 10 test positions, optional |
92-20
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Dry block bath for sample preconditioning, 20 test positions, optional |
LVDV II+Pro
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Brookfield digital viscometer and DV configuration software |
LB-VR
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Viscometer clamp assembly (included with visc. purchased from Lawler) |
Wingather
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Data capture software from Brookfield |
#4B2
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Insulated viscometer spindle, each |
LB-F
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Test cells, per dozen. (Do not use air chamber test jars) |
LB-Z
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Test cell stopper, each |
LB-K
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Test cell cover, each |
N27B
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Reference Fluid, pint -40°C to -18°C (37,000 cP @ -40°C) |
N115B
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Reference Fluid, pint -29°C to - 7°C (12,000 cP @ -12°C) |
N14B
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Reference Fluid, pint 17,000 cP @ -40°C |
N60B
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Reference Fluid, pint 150,000 cP @ -55°C |
N120B
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Reference Fluid, pint 150,000 cP @ -40°C |
N480B
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Reference Fluid, pint 150,000 cP @ -26°C |
N1400B
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Reference Fluid, pint 150,000 cP @ -12°C |
UPG-1
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Upgrade kit for converting older Model LB-76 to PC Control |
UPG-2
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Upgrade kit for converting older Model LB-76-2 to PC Control |
LB76-Kit
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Recommended Accessories for LB76 or LB76-G. Includes: |
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(2) LB-F, (10) LB-Z, (14) #4B2, (10) LB-K, (1) LM-PC |
LB76-2-Kit
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Recommended Accessories for LB76-2 or LB76-2G. Includes: |
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(3) LB-F, (20) LB-Z, (25) #4B2, (20) LB-K, (1) LM-PC |
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Note1: Kits do not include Brookfield Viscometer, purchased separately
Note2: Recommended are at least 2 reference fluids for each desired test temp./visc.
Specifications are subject to change without notice. |
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