Model BBV-1000 for the Annealing & Strain Point Temperatures

or for the Log 14.0 to Log 9.0 Poise Viscosity Range

 

The Model BBV-1000 series instrument is a versatile beam bending viscometer system that can determine either the annealing & strain point temperatures of a solid glass beam according to the ASTM C-598 procedure, or determine the temperatures for a range of viscosities of a solid glass beam according to the ASTM C-1350m procedure.

The annealing and strain points of a glass are widely used production control parameters. Changes in the annealing and strain point temperatures are indications of chemistry changes. If forming a fiber is not desired, is impractical, or impossible, annealing and strain point temperatures can still be determined using cut or machined rods or bars in a beam bending viscometer according to ASTM C-598.

(Note: If forming a fiber is desired, annealing and strain point temperatures can be determined by the Weighted Fiber Elongation Method, ASTM C-336.)

The annealing point temperature is the temperature at which a 2-point supported horizontal bar or rod with a uniform cross section deflects under an applied mid-point load at a prescribed calculated rate while cooling in a special furnace at the rate of 4°C per minute. The strain point temperature is determined by extrapolation of the annealing point data and is the temperature at which the mid point deflection rate is 0.0316 times the deflection rate observed at the annealing point.

These tests are performed with an LVDT extensometer system that is manufactured by Orton. The Model BBV-1000 Series has been designed to automatically monitor the deflection of the sample beam and calculate the annealing and strain points according to the ASTM C-598 method, or calculate the temperature for a range of viscosities according to the ASTM C-1350M method.

 

Automatic Annealing & Strain Point Determination

It is easy to measure the annealing and strain points or the temperatures for a range or viscosities of a glass beam. The operator enters the beam dimensions into the computer system, places the beam onto the sample support, applies the weight, aligns the LVDT, begins the test, and walks away. The system does the rest. The operator is free to perform other tasks. A little while later, either the annealing and strain point temperatures are automatically displayed on the computer monitor, or a table of the viscosity / temperature relationship is available. It's that easy. Model BBV-1000 automatically measures and calculates the rate of beam deflection, displays the annealing point temperature, extrapolates the strain point temperature. This eliminates operator differences, operator judgments, operator biases, and errors. Model BBV-1000 is an EASY, ACCURATE, RELIABLE, and REPRODUCIBLE instrument for R&D and for QC checks on batch chemistry changes.

EASY: The operator requires little training. After the test fiber is prepared, the operator enters the dimensions, places the beam onto the sample support, applies the weight, clicks the START button on the computer monitor, and walks away. The system does the rest, and the operator is free to perform other tasks. Upon test completion a short time later, the annealing & strain point temperatures are displayed on the computer monitor, or a table of the viscosity / temperature relationship is available.

ACCURATE, RELIABLE, and REPRODUCIBLE: The LVDT system automatically monitors the beam deflection, the computer calculates the rate of deflection, and the computer determines the annealing & strain point temperatures, or calculates the viscosities for the test temperature range. Operator differences, errors, and biases are eliminated. With good beams, ±1°C is routine.

FLEXIBLE: The user can select the ASTM C-598 procedure, or modify the thermal cycle for individual testing requirements, such as high volume QC testing. The Model BBV-100 can also determine the viscosity / temperature relationship for the viscosity range of log 14.0 to log 9.0 poise according to ASTM C-1350M.

POWERFUL: The data acquisition software displays the test and conditions while the test is underway. The data review software shows the test results, and generates a report that automatically compares the test results for a series of beams.

Description

Photo of Model BBV-1000 System Concept Drawing of Model BBV-1000 System

Model BBV-1000 Series
(required computer system not shown)

Concept Drawing of Model BBV-1000

The Model BBV-1000 Series was designed to provide the user with the choice to operate according to the ASTM C-598 procedure, according to a user-modified version of the ASTM C-598 test, or according to the ASTM C-1350M procedure. Through the special Orton software loaded into the user supplied computer, the user selects the mode of operation, inputs the appropriate information, and the Orton software does the rest. The Orton software controls the thermal cycle, acquires the data, and analyzes the data according to the mode selected by the user.

The Model BBV-1000 system is comprised of a special furnace to heat the beam, a control system to heat and cool the furnace, a thermocouple to monitor the beam temperature, an LVDT system to monitor deflection of the test beam, a software system to determine the annealing & strain points or the viscosities of the test temperature range, and a software system for generating comprehensive or summary reports.

Operation (ASTM C-598 Procedure)

After the sample beam (rod or bar) is prepared, the operator simply lifts the furnace up, places the beam on the sample support, lowers the furnace, enters the sample dimensions and other set up criteria into the PC loaded with the Orton software, applies the weight, clicks the START button, and walks away. The Orton software instructs the PID controller to heat the furnace from the staring temperature (25°C below the estimated annealing point temperature) at 5ºC per minute. The temperature and LVDT signals of the deflecting beam are captured by the software where the deflection rate is calculated and monitored. Once the deflection rate exceeds the pre-calculated turnover point, the Orton software instructs the PID controller to cool the furnace at 4°C per minute. While the furnace is cooling, the temperature and LVDT signals are captured by software for processing and storage. Once the deflection falls below the maximum deflection rate, the test is concluded and the annealing point temperature and the strain point temperature (the temperature at which the deflection rate is 0.0316 times the annealing point rate) are displayed on the computer monitor. The furnace automatically cools to the next starting temperature and waits for the next test.

Operation (ASTM C-1350M Procedure)

After the sample beam (rod or bar) is prepared, the operator simply lifts the furnace up, places the beam on the sample support, lowers the furnace, enters the sample dimensions and other set up criteria into the PC loaded with the Orton Software, applies the weight, clicks the START button, and walks away. The Orton Software instructs the PID controller to heat the furnace from thee starting temperature at 5°C per minute. The temperature and LVDT signals of the deflecting beam are captured by the software where the deflection rate is calculated and monitored. The software used the formula in the ASTM procedure to calculate the viscosity for the glass beam at that temperature, and generates a table of that data. The furnace automatically cools to the next starting temperature and waits for the next test.




Descriptions and specifications contained in this page are for general discussion purposes, and are subject to change without notice. Please consult Orton for clarifications and specific details.

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