The Orton Model RSV-1600 Viscometer is designed to measure the viscosities of a molten glass at various temperatures according to the ASTM C-965 Procedure A. The Model RSV-1600 is a rotating spindle viscometer using the constant angular velocity method to measure viscosities at specific temperatures in order to generate a curve of the visco-elastic behavior of a molten glass, as shown below. This system can also be used for testing according to ASTM C-1276 and ISO 7884/2 guidelines.
Operation (Isothermal Method)
The molten glass is held at a predetermined soak temperature until the thermal equilibrium is reached, and is monitored by the sample thermocouple at the base of the crucible, which sends its signal to the digital display in the UTC console. The spindle is manually lowered into the molten glass and the Brookfield viscometer rotates the spindle at a predetermined rotational speed. The readings on the Brookfield display are manually monitored and recorded as a function of rotational velocity and glass temperature. This process is repeated for a variety of rotational speeds and a variety of soak temperatures. Data is compiled and the viscosities are calculated according to the ASTM C-965 Procedure A guidelines.
The furnace position is fixed on the support structure. The crucible pedestal is raised and lowered into and out from the furnace via a motorized lift system for safe and easy handling of a crucible of molten glass. The photo at the right shows the pedestal in the lowered position for crucible loading and unloading. The rotating spindle assembly and viscometer head are manually lowered into and raised from the crucible of molten glass. The entire system is designed around the purchaser’s crucible size, range of viscosities, component movement method, and budgetary constraints.
The Model RSV-1600 can be enhanced to perform viscosity measurements during a programmed heating or cooling cycle. Consult with Orton for these details.
Platinum Crucibles & Spindles
The crucible and spindle are normally made from platinum. Due to the high cost of platinum, and the volatile nature of platinum prices, Orton encourages the user to suppply the crucibles and spindles in platinum. Most glass companies have access to low cost platinum and can obtain these components at a fraction of the cost it would be from Orton. Orton will work with the purchaser and will provide the engineering details for the crucible and spindle designs so the purchaser can obtain these components directly from platinum suppliers at a significant cost savings to the purchaser.
Computer Software Options
Orton offers a computer software option for Remote Programming the process controller, Data acquisition and Data Analysis.
Model RSV-1600 Specifications
Sample Crucible - System made to suit Purchaser’s crucible size (supplied by Purchaser)
Viscometer Spindle - Design to suit the crucible (supplied by the purchaser according to Orton specifications)
Maximum Temperature - 1600°C
Heating Element - Molybdenum Disilicide
Temperature Control System - Honeywell PID controller
Rotational Viscometer - Brookfield Series – choice of log viscosity ranges:
log 2.0 to 5.5 (poise)
log 1.4 to 4.9 (poise)
log 1.0 to 4.6 (poise)
Power Requirements - 240 VAC, 20 amp, 50/60 Hz (step down transformer included)
|Concept Drawing of Model RSV-1600
| Orton designs the system to accomodate the platinum crucible provided by the end user. A typical platinum crucible is 74mm tall with top diameter 68mm and bottom diameter 41mm. Capacity is approximately 200mL of molten glass.
|The crucible containing the glass sample is positioned on the top of the pedestal, and is heated by the vertical tube furnace with molybdenum disilicide heating elements and type “S” control thermocouple. The Process Control console (not shown) contains a multi-segment user programmable PID controller, phase angle fired SCR, current limiting power control module, ammeter, and digital temperature display, and is used to control the thermal cycle of the furnace during the various ramps and holds.
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