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Viscometry components

PVS control unit

The PVS control unit is the switching station between the PC and the individual components of the viscosity measuring system and, using one of the three selectable modules, coordinates the tasks and operations of all other parts of the system. The unit can be fitted with up to 4 modules:

The 1-place module (only on the PVS 1/1) provides a low-cost single-place measuring system with the option of adding measuring places at any time. This module can operate a single test stand S5 and can also coordinate the operation of a VRM 1 or a VRM 2 rinsing module with the stand, if required.

The 2-place module is the standard module of the viscosity measuring system. It can operate up to two measuring stands S 5 and one VRM 1, VRM 2 or VRM 2/HT type module.

To obtain an odd number of measurement places, a 2-place module can also be connected to a single stand S 5.

The burette module enables the connection of 1 or 2 dosing systems (burettes). These dosing systems are used for automatic concentration variation in one of the methods for determining intrinsic viscosity (= limit viscosity = Staudinger Index).

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Intelligent test stand

The test stand S 5 performs the complete viscosity measurement and uses light sensors to determine the run-out time of the liquid from the viscometer placed in the stand. The stand can support the most common types of conventional glass capillary viscometers (e.g. Ubbelohde, Cannon-Fenske Routine, etc.).

The stand S 5 has been fitted with a micro pressure pump and valves that are completely resistant to chemicals. In combination with a single-chip control, this permits the extremely compact arrangement of all elements required for the measuring inside the head of the stand. In addition, the single-chip controller provides an innovative form of control and adjustment of the infrared light sensors, resulting in a greatly extended optical evaluation range. The same single-chip processor also performs the time measurement to a millisecond accuracy so that the entire measurement process is performed on this test stand.

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The dosing system

The dosing system in the form of a burette is used to determine the limit viscosity through different concentration steps. It can be used only in conjunction with the burette module.

Rinsing modules VRM 1, VRM 2, VRM 22/HT
To achieve optimum results in widely different applications, the existing rinsing program can be adapted individually for each measuring place. Special features of the VRM 1 and VRM 2 modules are the use of two freely selected rinsing liquids (solvents) and their strict separation during the rinsing process and also during disposal, after the rinsing is completed.

The VRM1 rinsing module allows fully automatic rinsing and drying of a single viscometer.

The VRM2 can be linked to either one or two viscometers.

The VRM22/HT serves especially for capillary rinsing when using very hot samples, such as dissolved polyolefines or mineral oils above 80°C.

The main consideration in the use of VRM modules is the chemical resistance of all components that come in contact with the liquid, without excepting any of the usual solvents. This applies to a maximum temperature of up to +160 °C (VRM 22/HT).

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Capillary viscometers

All of the viscometers with aspirating tubes are designed for connection to the VRM rinsing modules for automatic rinsing. Rinsing modules can be connected to viscometers without an aspirating tube only in exceptional cases.

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