RU2475730C1 - Device for determining dryness degree of damp steam flow - Google Patents

Abstract

FIELD: heating.

SUBSTANCE: device includes the following: steam line with pressure and temperature metres, with steam sampling station; heat exchanger; steam supply line to heat exchanger from steam sampling station; cold water supply line, with flow metre, with pressure and temperature metres; computer with connected outputs of metres includes the following: heat exchanger that does not mix the condensate of extracted steam with heated water; discharge line of extracted steam condensate, with flow metre, with pressure and temperature metres; heated water removal line, with temperature metre.

EFFECT: use of this invention allows avoiding mixing of heated water with condensate of extracted steam sample.

1 cl, 1 dwg

Description

FIELD OF THE INVENTION

The invention relates to technical physics, and in particular to the field of control of technological parameters, and can be used to determine the degree of dryness of the flow of wet steam in steam pipelines.

State of the art

An analogue of the invention is a device comprising: a steam line with a pressure meter and a temperature meter, with a steam sampling unit; heat exchanger; a steam supply line to the heat exchanger from the steam sampling unit. [Patent No. 2046328 (RU), IPC G01N 25/60; A device for determining the degree of dryness of a stream of wet steam, A.V. Kovalenko, 1995; Bulletin of inventions No. 29].

With the essential features of the invention, the following combination of features of the analogue coincides: “a device comprising: a steam line with a pressure meter and a temperature meter, with a steam sampling unit; heat exchanger; steam supply line to the heat exchanger from the steam sampling unit. ”

The disadvantages of the analogue are:

A. The periodic nature of the work.

B. Long-term recovery to prepare for the (each) next procedure for determining the degree of dryness.

B. Lack of automation.

A prototype of the invention is a device comprising: a steam line with a pressure meter and a temperature meter, with a steam sampling unit; a heat exchanger mixing the condensate of the sampled steam with heated water;

a steam supply line to the heat exchanger from the steam sampling unit; cold water supply line with a flow meter, with a pressure meter and a temperature meter;

a line for removing a mixture of heated water and condensate from a sample of steam with a flow meter, with a pressure meter and a temperature meter; a calculator with connected outputs of the meters [Patent No. 2380694 (RU), IPC G01N 25/60; A method of controlling the degree of dryness of wet steam, A.V. Kovalenko, 2010; Bulletin of inventions No. 3].

With the essential features of the invention coincides with the following set of features of the prototype:

“A device comprising: a steam line with a pressure meter and a temperature meter, with a steam sampling unit; heat exchanger; a steam supply line to the heat exchanger from the steam sampling unit; cold water supply line with a flow meter, with a pressure meter and a temperature meter; a calculator with connected meter outputs. "

The disadvantage of the prototype is:

A. Mixing heated water with condensate from a sample of steam.

SUMMARY OF THE INVENTION

The problem to which the invention is directed, is: a device for determining the degree of dryness of a stream of wet steam.

When carrying out the invention, the following technical result can be obtained:

A. Determining the degree of dryness of wet steam without mixing heated water with condensate of a sampled steam.

The specified technical result is achieved by the fact that the device containing:

Steam line with pressure meter and temperature meter, with a steam sampling unit; heat exchanger; a steam supply line to the heat exchanger from the steam sampling unit; cold water supply line with a flow meter, with a pressure meter and a temperature meter; a computer with connected meter outputs;

contains:

a heat exchanger that does not mix the condensate of the selected steam with heated water; a condensate drain line for the selected steam with a flow meter, with a pressure meter and a temperature meter; heated water discharge line with temperature meter.

Signs that distinguish from the closest analogue are expressed by the following set of signs: "contains:

a heat exchanger that does not mix the condensate of the selected steam with heated water; a condensate drain line for the selected steam with a flow meter, with a pressure meter and a temperature meter; heated water drain line with temperature meter. ”

Thus, the objective of the invention is solved.

List of drawings

Fig. 1. A device for determining the degree of dryness of a stream of wet steam.

Information confirming the possibility of carrying out the invention

Fig. 1 shows a diagram of a device for determining the degree of dryness of a wet steam stream. This device contains:

- steam line 1 with static pressure meters 2, with a node for sampling steam 3;

- heat exchanger 5, not mixing the condensate of the selected steam with heated water;

- a steam supply line 4 to the heat exchanger 5 from the steam sampling unit 3;

- a cold water supply line 6 with a flow meter 8, with a pressure meter 9 and a temperature meter 7;

- a condensate drain line of the selected steam 12 with a flow meter 14, with a pressure meter 15 and a temperature meter 13;

- line 10 drainage of heated water with a temperature meter 11;

- calculator 16 with connected outputs of the meters 2, 11, 13, 14, 15, 7, 8, 9.

The proposed device can be implemented from technological units and meters used in existing steam supply systems.

On line 4, a steam sample taken from the steam line 1, through the site of sampling steam 3 enters the heat exchanger 5.

The condensate of the sampled steam is removed from the heat exchanger 5 through the condensate drain line 12.

On line 6, cold water is supplied to the heat exchanger 5.

Heated water from the heat exchanger 5 is discharged along the drain line 10.

The outputs of the sensors of the meters of the device are connected to the inputs of the calculator 16.

The ability to carry out the operation of the device is shown by an example of calculating the degree of dryness from the signals of its meters. During the experiment, the following values of the measured parameters were recorded for the selected time instant:

- cold water flow - G _hol.vody = 30,0 t / h;

- the temperature of cold water - t _hol.vody = 15,0 ° C;

- the temperature of the preheated water - t _gor.voda = 85,0 ° C;

- the pressure of the cold water - _hol.vody P = 0.3 MPa;

- pressure in the steam line - P _steam = 6.5 MPa;

- steam condensate flow rate - G _cond . _pair = 10.0 t / h;

- steam condensate temperature - t _cond.para = 120.0 ° С;

- vapor condensate pressure - P _cond.para = 0.3 MPa.

1. Heat taken from steam for heating cold water:

Q _{podogreva_vody hol.vody} = G · (t -t _{gor.voda hol.vody)} · c =

= 30.0 · 1000/3600 · (85.0-15.0) = 583.33 kcal / s;

where: c is the heat capacity of water.

2. Heat in the condensate of the selected steam:

Q is the _{heat in the condensate} = G _cond . _Pair · t _cond . _Pair · c =

= 10.0 · 1000/3600 · 120.0 = 333.33 kcal / s.

3. Enthalpy of the selected steam:

i = (Q _{water_heating} + Q _{heat in the condensate} ) / G _cond . _pair =

= (583.33 + 333.33) / (10.0 · 1000/3600) = 916.66 / 2.27 = 403.81 kcal / kg.

4. The heat content of water at the boiling point at a pressure in the steam line of 6.5 MPa:

Q of _water = 295.3 kcal / kg.

5. The heat of vaporization in 1 kg of wet steam:

Q _{p VP} = iQ _water = 403.81-295.3 = 108.51 kcal / kg.

6. The latent heat of vaporization at a pressure (6.5 MPa) in the steam line:

Q _p = 378.2 kcal / kg.

7. The degree of dryness:

x = Q _{f ch} / Q _f = 108.51 / 378.2 = 0.27.

Claims (1)

A device for determining the degree of dryness of a wet steam stream, comprising: a steam line, with a pressure meter and a temperature meter, with a steam sampling unit; heat exchanger; a steam supply line to the heat exchanger from the steam sampling unit; cold water supply line, with a flow meter, with a pressure meter and a temperature meter; calculator, with connected outputs of meters; contains: a heat exchanger that does not mix the condensate of the selected steam with heated water; a condensate discharge line for steam to be taken, with a flow meter, with a pressure meter and a temperature meter; heated water drain line with temperature meter.