SU964036A1 - Apparatus for monitoring cloth density - Google Patents

Description

The invention relates to the field of automatic devices for quality control of materials and is intended for use in the textile industry in the weaving and finishing industry.

A device for controlling the density of a web is known, which contains sources of radiation and photodevices located on opposite sides of the web, a driver, and a signal processing unit 1.

A disadvantage of the known device is a decrease in the accuracy of density control with a decrease in the speed of transporting the web due to the deterioration of the pulse formation conditions carrying information about the density of the material.

The aim of the invention is to improve the accuracy of control while reducing the speed of the web or stopping it.

The goal is achieved due to the fact that the device containing the radiation source and photoreceivers located on different sides of the web, the former and the information processing unit, has an additional sawtooth generator, a constant bias source, an amplitude selection unit, a differentiating amplifier, a logical

the NAND block and the computing block, the photodetector being designed as a scanner, the first power input of which is connected to the first outputs of the constant bias source and sawtooth generator, as well as the first input of the amplitude selection unit, the output of which is connected to the first input computing unit and the first input

10 of the logical NAND unit, the second input of the sawtooth generator is connected to the readout input of the photon receiver and, through the differentiating amplifier and the former, is connected to

15 to the second input of the logical unit IS-NOT, the output of which is connected to the second input of the computing unit, while the second power input of the photodetector is connected to the second output of the constant source

20 offset.

The drawing shows a block diagram of the device.

The device for monitoring the web DENSITY contains radiation source 1 and

25 photodetector 2, located on different sides of the blade 3, differentiating amplifier 4, driver 5, logical block AND-NOT 6, sawtooth voltage generator 7, source of constant mixing 8, amplitude selection unit 9 and.

computational unit 10. Amplitude selection unit 9 consists of trigger elements 11 and 12, AND-HE schemes 13 and 14 and trigger 15. The device is mounted on a weaving flock in the free space between the chest 16 and the val 17.

The device works as follows.

The light note from the radiation source 1 passes through the canvas 3 to the photo scanner-scanstor 2. In this case, a sequence of dark and light knots are formed on the surface of the scanstors 2, corresponding to the type of non-reflections of the canvas 3, which is converted into an electrical signal. The signal from scanner 2 is differentiated by differentiating amplifier 4, at the output of which a sequence of pulses is formed. The shaper 5 generates, from these NMRs, square-shaped impulses, which are fed to the input of the logical block AND-NOT 6. The voltage from the sawtooth generator 7 enters the amplitude-selection block input 9, by means of which the time interval is separated. from the sawtooth voltage generator 7 reads information from that part of the scanner 2 onto which the image of the web is projected (the working section of the scanstor). The threshold element 11 forms a voltage impulse, the leading front of which corresponds to the beginning of reading information from the working section of the scanstor, and the threshold element 12 forms the voltage pulse, the leading front of which corresponds to the copy of the working section of the transistor.

From the output of the threshold elements 11 and 12, the signals are respectively fed to the inputs of the NAND circuits 13 and 14, which invert the signals. With the help of trigger 15, a pulse is formed, which allocates and, for a time interval, information is read from the working section of the signal of the Oxister 2. From the output of trigger 15, the signal goes to the first inputs of the logical block IS-NOT 6 and the computing unit 1Q. Since the second input of the logical block IS-HE 6 also supplies a signal from the output of the imaging unit 5, pulses are output from its output, which are fed to the second input of the computing unit 10 and correspond to the number of threads projected on the open-loop 2 in one turn of the scan. generator sawtooth voltage 7.

The computational block 10 processes the information supplied to its first and second inputs, / to estimate the web density using the formula

about . // LL. 7 1,

-).

(one)

where N is the number of pulses received from the output of the logical block AND-NOT 6;

n is the number of pulses received from the 5th output of the amplitude selection scheme 9;

/ (- coefficient of propionality, depending on the degree of increase in the optical system;

0T - the time of the forward sweep

sawtooth generator 7;

/ - the length of the working section of the scanner 2; 5V - web speed on

weaving machine.

Since the time of the forward stroke sweep of the sawtooth generator 7 is in thousands of fractions of a second, the length 0 of the working section of the scanner is 2–20 mm, and the speed of movement of the web ia is weaving

T

mm / s, then -.

mnol

V-1

t

a) in formula (1) you can

1 ±

body

......, l

neglected. Then the density of the web is calculated as follows:

L

The use of this device makes it possible to improve the quality and grade of a textile material by increasing the accuracy of controlling its density, regardless of the speed conditions of its movement.

Claims (1)

1. Copyright svdedelstvo USSR № 526688, cl. D 06 H 3/16, 1976.