Brookfield Thermosel DV-II+

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Overview

Function Description
Important Technical Specifications
Usage Features
Maintenance Features

The Brookfield Thermosel Accessory is a specialized system designed for accurately measuring the viscosity of liquids at elevated temperatures. It integrates with Brookfield Viscometers or Rheometers to provide precise viscosity measurements using coaxial cylinder geometry. The system's core function is to control and maintain the sample material, spindle, and chamber at a desired temperature, facilitating viscosity analysis of materials that are liquid only at higher temperatures or require temperature-controlled testing.

Function Description:

The Thermosel System operates by controlling temperature through a solid-state, triac output, Proportioning Controller. This controller ensures that the sample, spindle, and chamber reach and maintain the set temperature. Viscosity measurements are then obtained using a connected Brookfield Viscometer or Rheometer. The system is particularly useful for materials that are solid or semi-solid at ambient temperatures, allowing them to be tested in their liquid state.

The operational procedure involves several key steps:

Setup: The viscometer and stand are positioned on a firm, level surface, connected to an appropriate electrical service. Cooling water supply and drain are recommended for the thermo-container. The viscometer is attached to the stand, leveled, and raised to its highest position.
Alignment: An alignment bracket is attached to the viscometer pivot cup. The thermo-container and its base are leveled using three knurled screws. The viscometer is then lowered until the alignment bracket tips touch the locating ring's horizontal surface, with a specific 1/16 inch reference point for proper alignment.
Sample Chamber Insertion: The sample chamber (HT-2 or HT-2D) is inserted into the thermo-container using an extracting tool, rotated until it locks in place.
Controller and Probe Connection: The controller is placed adjacent to the thermo-container. The thermo-container's braided cord is plugged into the controller, and the stainless steel probe (Resistance Thermometer) is inserted into the thermo-container and connected to the controller. A critical safety note emphasizes that the probe must be inserted before turning on the controller to prevent overheating and damage to the thermo-container.
Spindle Insertion: Depending on the spindle type, either a solid shaft spindle (SC4-**BS) is carefully lowered and threaded onto the viscometer (left-hand thread), or a spindle requiring an extension link and coupling is assembled and threaded. The spindle coupling nut or pivot screw should be gently pushed up during this process. An insulating cap is then placed over the sample chamber inlet.
Viscosity Measurement for Liquid Samples: For samples liquid at ambient temperature, the insulating cap and spindle are removed, the viscometer is raised, and the sample chamber is removed and placed in a holder. The specified volume of liquid sample is poured into the chamber, which is then re-inserted into the thermo-container. The viscometer is lowered and aligned, and the spindle is re-connected, ensuring the liquid level is 1/8 inch above the conical surface of the spindle shaft (avoiding overfill). The insulating cap is replaced. The controller is turned on and set to the desired temperature. Once temperature equilibrium is reached (indicated by a steady display and flashing "ON" light on the controller), viscosity readings can be taken at various speeds. For non-thixotropic or pseudoplastic materials, the viscometer can be left running during equilibrium to aid agitation and reduce temperature gradients.
Viscosity Measurement for Non-Liquid Samples: For samples solid or semi-solid at room temperature, the instrumentation is assembled without the sample chamber, spindle, and insulator cap. The controller is set to the desired temperature. The required amount of test sample (equivalent to the liquid state volume) is weighed into the sample chamber. The chamber is then placed into the thermo-container, and the procedure for liquid samples (starting from page 6 of the manual) is followed.

Important Technical Specifications:

Temperature Range: The system is designed to operate from 40°C (104°F) up to a maximum of 300°C (572°F). The lower limit of temperature control is approximately 40°C (104°F).
Temperature Accuracy:
- ±1.0°C for temperatures between 100°C and +150°C.
- ±2.0°C for temperatures between +150°C and +300°C.
Viscosity Range: From 5 cP to 8,000,000 cP, depending on the specific viscometer and SC4 spindle utilized.
Electrical Service: Requires a 15 amp, 115 or 230 volt, 50 or 60 Hz grounded A.C. power supply.
Heating Time: The controller brings the thermo-container to an elevated set point temperature in approximately 30 minutes.
Cooling Time: Unassisted cooling from 260°C (500°F) to 37°C (100°F) takes approximately four hours. Using the cooling plug (HT-26Y) with circulating tap water (at 1 gal/min and 51°F) can reduce this to about 20 minutes.
Spindle Types: Includes standard SC4 series spindles and solid shaft spindles (SC4-**BS option) for "stiff," slow-flowing materials like candy base, highly-filled epoxies, pastes, and asphalts. Solid shaft spindles minimize "walking" (eccentric rotation).
Sample Chamber Volume: Varies depending on the spindle used, as detailed in the Viscosity Ranges/Spindle Factors appendix (e.g., 8.0 mL for SC4-18, 10.0 mL for SC4-31 and SC4-34, 10.5 mL for SC4-27, 11.5 mL for SC4-28, and 13.0 mL for SC4-29).

Usage Features:

Coaxial Cylinder Geometry: Provides accurate viscosity measurements.
Solid State Proportioning Controller: Ensures precise temperature control.
Cooling Plug (HT-26Y): Significantly reduces cooling time for the thermo-container, enhancing operational efficiency.
Disposable Sample Chambers (HT-2DB): Available for difficult-to-clean materials or to improve productivity in busy laboratories. These are inserted/removed using HT-116 pliers.
System Alignment: Detailed instructions for aligning the viscometer, stand, and thermo-container ensure accurate and repeatable measurements.
Spindle Compatibility: Supports various viscometer models (LVT, LVF, RVT, RVF, HAT, HBT, DV-E, DV-I+, DV-II+, DV-III+) with corresponding SC4 series spindles.
Temperature Conversion Table: An appendix provides a conversion table for Centigrade to Fahrenheit and vice versa.

Maintenance Features:

Cleaning: The spindle and sample chamber are made of stainless steel and can be cleaned with most commercial solvents. However, they should not come into contact with Sulfuric Acid, Hydrofluoric Acid, Ferric Chloride, or Hydrochloric Acid solutions. Mechanical action may be required to scrape out the chamber.
Disposable Chambers: Disposable sample chambers (HT-2DB) eliminate the need for cleaning and can be discarded after use, simplifying maintenance for certain applications.
Calibration: The manual recommends verifying system calibration using suitable viscosity standard fluids if viscosity measurements are suspect. High Temperature Calibration Fluids (HT-30,000, HT-60,000, HT-100,000) are available for this purpose.
Warranty: Brookfield Thermosel Accessories are guaranteed for one year from the date of purchase against defects in materials and workmanship. Warranty repair requires returning the instrument to Brookfield Engineering Laboratories, Inc. or an authorized dealer/distributor/representative. Transportation costs are at the purchaser's expense.
Service and Support: Contact information for Brookfield Engineering Laboratories, Inc. in the United States, United Kingdom, and Germany is provided for repair, service, and purchasing calibration fluids or disposable chambers.