SU882902A1 - Material edge position pneumatic sensor - Google Patents

Description

(54) nHEB.iHATHMECKHH MATERIAL EDGE POSITION SENSOR

I

The invention relates to means of controlling the textile industry, namely pneumatic sensors for positioning the edge of a material.

A pneumatic sensor for positioning a material edge is known, comprising a housing made in the form of a bracket, the jaws of which have channels that are led out into slots (1.

A disadvantage of the known sensor is insufficient sensitivity. This disadvantage is explained by the non-linearity of the change in transmission coefficient due to the non-linear velocity profile of the flow coming from the narrowing gap, the maximum flow rate in this case being in place of the maximum equivalent gap diameter, and the minimum flow rate in the middle of the gap.

The disadvantages of the known sensor should also include the lack of coaxial exhibition output and receiving slits, as well as the optimal setting of the width of the slit nozzles.

The purpose of the invention is to increase the sensitivity and simplify the adjustment of the sensor.

The goal is achieved by the fact that the pneumatic sensor has placed

in the slots of the jaws there are sliding strips, the ends of which form a supply and a receiving nozzle, while the strips of the receiving nozzle have a variable thickness along the groove, decreasing in the course of the air supply from the edges to the middle.

FIG. 1 shows the sensor section; in fig. 2 is a view A of FIG. one; in fig. 3 is a section BB in FIG. 2; in fig. 4 - sensor, top view; in fig. 5 is a sectional view BB in FIG. four.

to

The sensor contains the upper jaw I on which the lining 2 is installed with sliding bars 3. The lining 2 is fixed to the jaw with screws 4, and the lath 3 is fixed to the lining by 2 screws 5. The lining 2 has

.J hole 6 communicated through channel 7 with hole 8 for supplying compressed air. The feeding nozzle is formed by the ends of the slats 3 with the possibility of adjusting the width of the nozzle by moving the slats 3 in the direction perpendicular to the plane

20 drawings ..

Claims (1)

The lower sponge of the sensor is an amplifier 9 containing a cover 10 on which a mounting pad 11 is coupled with strips 12, the ends of which form a receiving nozzle. The slats 12 have bevels 13 at the ends so that the receiving nozzle 14 is formed by the ends of a trihedral prism. This makes it possible to change the hydraulic resistance of the nozzle with decreasing it from the middle to the edges along the length of the nozzle. In terms of this, the nozzle slit is a rectangle. A diaphragm 15 connected to the spool 16 is installed under the cover 10. The spool is compressed by a spring 17. The amount of compressed air flow directed to the feed nozzle is adjusted by a screw 18. A cap 19 is installed on the upper jaw for optical control of the nozzles coaxiality. The sensor works as follows. At the neutral position of the edges of the material 20, the compressed air from the feed nozzle enters the right half of the receiving nozzle and through the opening 21 in the lid into the chamber above the diaphragm. Above diaphragm 15 a pressure is established such that the forces acting on the spool from the diaphragm and the springs balance the position of the spool with the cover of the opening 22 for supplying compressed air to the spool space. When the material edges are shifted to the right, the pressure on the diaphragm decreases, the spring raises the valve and the compressed air is directed into the hole 23 to control the actuator (not shown). When the material edge is shifted to the left, the air flow to the receiving nozzle increases and the pressure above the diaphragm increases. The force developed by the diaphragm overcomes the action of the spring on the valve. The spool is lowered down, and the compressed air is directed into the hole 24 to control the actuator. The feed nozzle is a rectangular pipe, so the flow rate of air from it is constant over almost the entire length of the nozzle. Therefore, the velocity head of air reaching the receiving nozzle along the entire length of the beginning of the low nozzle has a constant value. With the passage of air into the slot formed by the ends of the strips having a varying thickness from their midpoint to the edges along the slot length, a linear pressure drop occurs with a linear increase in pressure from the midpoint to the edges at the exit from the slot and the diaphragm. The value of the pressure drop at each point along the length of the slit at the exit from it and above the diaphragm can be estimated by the formula. P - (), where X is the coefficient of friction; L-slat thickness; d - nozzle width; I - coefficient of local resistance; W - air flow rate; Y is the specific gravity of air; g - free fall acceleration. Since the outflow from the receiving nozzle to the flow encounters a sudden expansion, the dynamic pressure almost completely becomes static with a linear increment of pressure along the length of the nozzle at a steady average pressure over the diaphragm due to air leakage from the part of the receiving nozzle covered by the material. In this way, a linear change in the pressure over the diaphragm and the corresponding control of the spool is obtained in proportion to the position of the material edge at a constant flow rate of air along the length of the slit from the feed nozzle. Pneumatic material position sensor, comprising a body made in the form of a bracket, the jaws of which have channels that are led out into slots, characterized in that, in order to increase the sensitivity and simplify the adjustment of the sensor, it has sliding jigs arranged in the slots of the jaws supply and receiving nozzles, with the receiving nozzle strips having a variable thickness along the groove length, decreasing in the course of the air supply from the edges to the middle. Sources of information taken into account during the examination 1. USSR Author's Certificate No. 639790, cl. B 65 N 25/08, 1978. FIG. 2 Fig.Z