DE2853678A1 - Continuous fluid viscosity measurement - by using flexible ended vibrating lever inside bored hole and having strain gauges producing electrical signals - Google Patents

Abstract

A viscosity sensor is used in continuous measurement of the viscosity of viscous materials such as molten plastics in extruders, enabling the viscosity to be regulated without the production process being interrupted or diverted. A two-arm lever (2, 3) is mounted in a cylindrical holder (1) via a sealed linkage (4) with its outer arm (2) held in constant amplitude oscillator motion by an eccentric motor drive (5) or electromagnet. The lower arm (3) protrudes into a fluid channel where its oscillation amplitude depends on the lever ration. Strain gauges (9) inside a hole (8) bored in the flexible part (8') of the lever arm produce electrical signals corresp. to the viscosity of the fluid. Foil of clamped resistance wire strain gauges may be used.

Description

Viscosity indicator

The primary purpose of the present invention is to reduce the viscosity of viscous substances, e.g. plastic melts, continuously within extruders to measure and control without interrupting or redirecting the production process.

The viscosity transmitter consists of a double-sided shaft 1 pressure-tight and moveable built-in lever 2-3, which is operated by a motor-driven Eccentric 5 or an electromagnet 6-6 'is set in oscillating motion.

A paddle-shaped lever attachment that dips into the mass to be measured 1o has a place that is unaffected by friction and other errors of the Drive, equipped with electrical measuring elements 9 bore 8, the axis when moving the bend due to the mechanical resistance of the more or less thick mass is subject and the walls 8 'alternately in the rhythm of the Compress and stretch movement.

These changes in length of the bore walls 8 'and the measuring elements 9 are a measure of the size of the viscosity. The measuring elements 9 are known Way in a bridge circuit and are reinforced as needed.

The lead out of the measuring lines 21 takes place shortly after the pivot point at 18 of the double-sided lever 2-3, so that there is no damage to the insulation. If higher oscillation frequencies of the lever 2-3 are required, the drive can do the same done by an electromagnet 6. At the outer end of the lever there is then an anchor 6 ' available.

Since it is optional, also the pressure and the temperature of the to be measured Detecting ground in the same zone can be built in for this purpose Measuring ring 13 available, which holds the three transducers 1o-14-15 in the complete arrangement contains, Fig. 5. In Fig. 6 you can see how the measuring elements 9 in the bore 8 are arranged on the thin walls 8 '.

Claims (13)

Patent claims viscosity transmitter characterized in that in a shaft-like holder (1) (Fig. 1) a two-armed lever (2-3) by means of a pressure-tight joint (4) is mounted so that the outward-reaching part (2) the same by a motor-driven eccentric (5) or an electromagnet (6) (Fig.2) kept in oscillating motion of preferably constant amplitude while the other lever part reaching into a container or channel (7) (Fig. 5) - (3) also carries out vibrations in a width, according to the lever ratios (2 to 3). 2 viscosity transmitter according to claim 1, characterized in that the in a container or channel (7) with liquid substances of consistency to be measured submerged lever part (3) is equipped with a flexible wall (8 ') in which Bores (8) strain gauges (9) in the form of foils or freely tensioned resistance wires are arranged in such a way that they generate electrical signals which are all the greater The thicker the material, the more mechanical resistance it causes and bends her swinging lever (3). 3 viscosity transmitter according to claim 1-2, characterized in that the flexible wall (8 ') in a lever part widened to form a flat paddle (lo) (3), so arranged by the hinge (4) and the self-bending of the driven lever (2) is that their sources of error have no influence on the measured values. 4 viscosity transmitter according to claims 1-3, characterized in that the eccentric (5) is driven by a motor (11) via a flexible shaft (12) will. 5 viscosity transmitter according to claims 1-4, characterized in that the transmitter is installed in this way in a channel or retaining ring (13) through which liquid flows is that the flat part of the paddle (lo) is parallel to the direction of flow (Fig.5). 6 viscosity transmitter according to claims 1-5, characterized in that in the measuring zone at the same time pressure sensor (14) and temperature sensor (15) in a common retaining ring (13) are installed. 7 viscosity transmitter according to claims 1-6, characterized in that the joint part (4) is designed in the shape of a bellows. 8 viscosity transmitter according to claims 1-7, characterized in that the bellows-shaped joint (4) is exchangeable. 9 viscosity transmitter according to claims 1-8, characterized in that the paddle (lo) is held on the joint (4) by means of a thread (16). Lo viscosity transmitter according to claims 1-9, characterized in that the eccentric (5) works against a return spring (17) of the lever (2). 11 viscosity transmitter according to claims 1-102, characterized in that the lever (2-3) is supported against a bearing (18) in the holder (1). 12 viscosity transmitter according to claim 1-11, characterized in that the motor (19) for driving the eccentric (5) directly on the base (20) of the Bracket (1) is attached. 13 viscosity transmitter according to claims 1-12, characterized in that the electrical leads (21) to the measuring elements (9) through a bore (22) in the lever (2) to a cable connection (23) so that they are close of parts (4) and (18) emerge from the lever (2).