RU1814038C - Well-type liquid-column glass-tube manometer assembly - Google Patents

Abstract

Usage: in pressure measuring devices. SUMMARY OF THE INVENTION: a transparent tube is welded with one end to the upper end of the bowl, and the other end of it is installed in a blind hole made in the thickened lower end of the bowl. The end of the tube in the hole is installed with a gap relative to its bottom, and its side surface is in contact with the surface of the blind hole, which provides increased reliability during transportation and storage of the pressure gauge assembly. 1 s l f-ly, 1 ill.

Description

The invention relates to the construction of glass cup pressure gauges.

The purpose of the invention is to increase the reliability of a glass cup pressure gauge assembly by increasing its average service life.

The proposed device is shown in the drawing and consists of a bowl 1 of inorganic glass with a first and second ends and a glass intra-cup measuring tube 2, the first end of which is welded to the first end of the bowl, and the second end is located below the surface 3 of the bottom 4 of the bowl inside the dead end cavity 5 above its bottom 6 and has a narrowing 7, the inner diameter of which is less than the inner diameter of the measuring section of the tube 2.

Tube 2 is equipped with a nozzle 8 for iodine-supply of negative pressure, the bowl 1 is equipped with a nozzle 9 for supplying positive pressure in relation to the negative pressure (both pressures can be both above and below atmospheric).

Clearance (gap) between the side wall of the measuring tube 2 and the side wall

dead-end onutridone cavity 5 lies within, for example, (0.2-1.0) mm.

The gap between the second end of the tube 2 and the bottom 6 of the cavity 5 lies within, for example, (0.5-3.0) mm; the inner diameter of the measuring tube 2, for example, (2.5-5.0) mm; the inner diameter of the narrowing 7, for example, (0.5-1.0) mm, i.e. in (5-10) times less than the diameter of the tube 2; bowl diameter 1, for example, (40-100) mm; bowl height 1, for example, (500-2000) mm.

The wall thickness of the bowl 1 and the measuring tube 2 lies in the range (1.0-3.0) mm; bottom height 4 (30-40) mm, taper height 7 (20-25) mm.

With a cup inner diameter of 1 40 mm, a tube inner diameter of 2 2.5 mm and a cup height of 1000 mm, the minimum required volume of gauge liquid is 5 cm3.

Measuring scale 10 can be applied directly to bowl 1 and calibrated in units of pressure and / or as a percentage of the nominal measured differential pressure.

ate

DGD

The proposed device operates as follows,

When measuring the differential pressure, the plus and minus pressures are supplied respectively to the fittings 9 and 8 of the bowl,

If the pressure drop is zero, the level of the gauge liquid in the tube 2 will be at 0% of the scale 10, if the pressure drop is equal to the nominal pressure drop, then the level in the tube 2 will be at 100%. In general, the measured pressure drop is determined by the formula

Dr. () g (Ahi-Aho). where Dp is the measured pressure drop;

g is the free fall coefficient (, 8 m / s2);

hw — density of the gauge fluid;

RG is the gas density in the manometer;

Long is the initial difference in manometric fluid levels at zero pressure drop due to the capillary properties of the fluid;

Ahj is the measured value of the difference in the levels of the gauge liquid in the bowl 1 and the measuring tube 2.

The hydraulic connection between the gauge fluid in the bowl 1 and the tube 2 is through a gap filled with gauge fluid between the side wall of the dead-end cavity 5 and the tube 2, as well as through the internal restriction channel 7, connected in series with the aforementioned gap.

It should be noted that the lateral gap shown between the elements (between elements 2 and 5) practically has the shape of a convex-concave gap, and not an annular one, since the tube 2 in the manufacture of the pressure gauge is absolutely not centered in the dead-end cavity 5, and there is no need in such a centering due to the small size of the gaps - (0.2-1.0) mm and the insignificance of mechanical stresses in the tube 2 with a height of more than 500 mm when moving its second end face up to 1 mm.

Due to the fact that the bottom 4 of the bowl 1 of the gauge assembly is made with a dead end intra-bottom cavity 5 and the second end of the tube 2 is located below the upper surface 3 of the bottom b of the bowl inside the cavity 5 with a clearance (0.5-3.0) mm from the bottom 6 and c (0,; b) mm from the side wall of cavity 5, an increase in the reliability of the device is achieved by increasing its average service life due to

restricting to (0.2-1.0) mm lateral movement of the second end of the tube 2 inside the dead end cavity 5 until it stops against its side wall. In addition, due to the location

the hydraulic communication channels of the bowl 1 with the measuring tube 2 completely inside the stub endonoid cavity 5 of the bottom of the bowl 1 reduces the volume of gauge fluid, the minimum required for

ensuring the operability of the proposed pressure gauge assembly.

Due to the fact that the bottom region of the tube 2 has a narrowing 7 with an inner diameter 5-10 times smaller than the inner diameter of the measuring section of the tube 2 and a substantial height, for example (20-25) mm, the minimum required volume of gauge fluid in the assembly is further reduced cup

the pressure gauge and, most importantly, the pulsation of the level of the gauge liquid in the tube 2 is further reduced when the pressure is pulsed through the nozzle 8, which facilitates the reading and improves the accuracy of the measurement of pulsating pressure drops.

The total annual effect of the full-scale application of the proposed units of the cup glass manometer

Claims (2)

1. The node of the pressure gauge cup glass liquid type containing a transparent bowl of inorganic glass, inside of which a transparent tube is mounted coaxially with it, welded by the first end to the first end of the bowl, and the said ends of the bowl and tubes are equipped with pressure fittings, which, in order to increase reliability, the second end of the bowl is made in it with a thickening, in which from the side of the inner cavity of the bowl a blind hole is made parallel to its axis with a diameter larger than the outer diameter of the tube, while the second end of the measuring tube is installed in the blind hole with a gap relative to its bottom, and the side The surface of the second end of the tube with one side in contact with the surface of the blind hole, 2. Knot pop. 1, characterized in that that, in it is a tube section located in blind hole, has a narrowing of the inner diameter, 5-10 times smaller than the inner diameter of the entire tube.