SU134496A1 - Instrument for measuring flow rate - Google Patents

Description

The proposed device for measuring the flow rate of a fluid by type of hydrometric tubes with piezometers allows, in contrast to the known instruments intended for these purposes, to measure small flow velocities, which greatly expands the range of application of such instruments.

FIG. shows the device in section; in fig. 2 is a diagram of its measuring part.

The device is made in the form of a cylindrical perforated tube / with an end opening. Inside the tube are placed: a hollow cylinder 2 suspended in a liquid with a shank of a smaller diameter than the diameter of the cylinder itself; a tube 3 of a velocity head with face and side openings 4, into which the shank of cylinder 2 freely enters; static pressure tube 5; aperture 6 with a hole and a plate 7 for fastening the tube to the rod.

The measuring part of the device consists of an lJ-shaped inverted differential pressure meter 8. The knee C differential pressure meter, which fixes the static head of the flow, is connected by means of a flexible hose to the tube 5, a static head, and the knee D, showing the velocity head, is connected through a tee to the tube 3 of the speed head. parts of the differential pressure gauge are placed in a small tank 9, to which is attached a hose connecting the tank with an adjustable valve 10 with a scale, calibrated in units of flow velocity.

The fluid from the tank 9 under the pressure of H flows through an adjustable valve 10 to the tee of the knee D.

In the tank 9, the liquid is supplied under pressure through a valve with a floating shut-off mechanism that provides a constant level of liquid in the tank, which compensates for the velocity head of the flow.

The velocity head of the test flow through the tube end opening exerts pressure on the cylinder 2. The counterbalancing pressure 134496-2 on the cylinder 2 stem from the side of tube 3 is performed by the velocity head of the outflowing fluid from the knee D through the side opening 4 of tube 3. In this case cylinder 2 It takes the position in which its shank opens half of the hole 4.

To keep the pressure in the knee D corresponding to the balancing pressure, through the tee of the adjustable valve 10, the amount of liquid supplied to the knee D is transferred under the pressure Zj from the knee D to the tube 3. Thus, the balance of the flow rate of the liquid coming from the tank 9 to the differential pressure gauge is set. under the pressure of HI and flowing out of the knee D into the hole 4 under the pressure of Z.

Subject invention

An instrument for measuring the flow rate of a fluid by type of hydrometric tubes with piezometers, characterized in that, in order to make it impossible to measure small flow velocities, the instrument is made in the form of a cylindrical perforated tube with an end opening, inside which are placed: a hollow cylinder suspended in a liquid with a smaller shank diameter than the diameter of the cylinder, a tube of velocity head with face and side openings, into which the tail of the cylinder freely enters, a tube of static pressure, a diaphragm and U-tube a different inverted differential pressure gauge, one knee of which is connected to the velocity head tube, is simultaneously connected via an adjustable valve with a scale, calibrated in units of flow velocity, to a movable tank with a constant level of liquid compensating the velocity head flow, and the second knee is connected to the static head tube .