SU1455121A1 - Method of softening water containing temporary hardness salts - Google Patents

Abstract

The invention relates to heat engineering and can be used in process plants and for domestic purposes. The purpose of the invention is to reduce material and energy costs. Water with temporary harsh salts is heated by mixing with recirculating hot water in a ratio that provides the mixture with a temperature above the maximum salt precipitation limit. This embodiment eliminates the need for expensive water treatment ion-exchange-type installations for small industries where hot water can be used for showers and heating, as well as for cooling. 1 il. with SS

Description

4 ate SP

The invention relates to heat engineering and can be used to soften WATER with salts of temporary rigidity in relation to technological installations for various purposes and for domestic purposes.

The aim of the invention is to reduce material and energy costs.

The drawing schematically shows a device for implementing the proposed method.

The device comprises a cold water pipeline 1 with a shut-off valve 2 connected to the tank 3 for descaling. Between the lower part of the tank 3 and the space above the water level H in the tank, piping 4 is installed with hot recirculating water with circulation pump 5 and heat exchanger 6. The output open end of pipeline 4 is located near the output open end of pipeline 1 of cold water, and the suction end is hii from the bottom of the tank 3.

A tray 7 is placed below the open ends of both pipes 1 and 4 in the space of the tank above the water level for pre-mixing of cold and hot water. A pipeline 8 is connected to the bottom part of the tank 3 to periodically discharge the sludge with scale to its side surface in the lower part at a distance h. from the bottom of the tank 3 - pipeline 9 for supplying heated and softened water to the consumer. A float 10 is provided for adjusting the level of water in the tank 3. It is connected to the electrical contacts 11 that control the pump 5. At the outlet section of the pipeline 4, a circulation pressure indicator 12 is installed connected to the shut-off valve 2

Water softening is performed as follows.

Heating of the softened water is carried out by mixing with recirculating hot water in the ratio of 5 to the temperature of the upper limit of the precipitation of temporary hardness salts. The mixture of water is sent to sludge and then heated to the required maximum temperature.

The ratio of the mass of hot water RG to the mass of cold water PX is determined by the formula

IL (TVP + t) - mx r.

t g - (4T)

0

five

0

five

0

five

0

five

where t

vp

Ui tv and t

-the temperature of the upper limit of the precipitation of salts of temporary rigidity, at which all salts of temporary rigidity pass into an insoluble temperature rise

  IN 1

- temperature of cold and hot water, respectively.

Exceeding the temperature (T) is necessary to accelerate the process of transition of temporary rigidity salts to an insoluble state in order to guarantee the completion of this process in the volume of the tank. Due to the different properties of hard water, the minimum numerical value should be determined experimentally depending on the properties of the water used, taking into account the design of the device.

In this formula, the change in heat capacity of water depending on its temperature is not taken into account due to its small value.

Example. Artezian water with salts of temporary rigidity in the form of calcium bicarbonate has an upper limit for the temperature of precipitation of salts of temporary rigidity (transition to calcium carbonate) Tgp equal to 363K (90 C), its temperature Tu equals 285K (12 C). Accepting a temperature of 4 T equal to 2K. In this case, the temperature of the mixture (Tg, -, + / 3 T) is 363 + 2 365K (92 ° C). The temperature of hot water is assumed to be 373K (). Ratio of hot and cold water

  (363 + 2) - 285 Ru 373 - (363 + 2)

 ten.

When the temperature of hot water decreases by 2K, the ratio

Pr (363 + 2) - 285 PX 371 - (363 + 2)

 20.

With an increase of 4 ° Pr (363 + 2) - 285

377 - (363 + 2)

 6.7.

314

In relation to the device shown in the drawing, hot water with temperature (T + T) by pump 5 through line 4 is pumped through heat exchanger 6, where it is heated to temperature T, and then goes to tray 7. On the same tray 7 from line 1 cold water flows at a temperature T; c and is mixed with hot water to a temperature (Tgp + / 3 T), then this mixture from tray 7 is discharged into tank 3, where the final scaling occurs and it settles to the bottom of the indicated tank. Periodically, sludge with scale is discharged from the tank 3 through the pipeline 8. The heated and softened water through the pipeline 9 is supplied to the consumer. When the pipeline 9 is located above the level of the suction side of the pipe 4 (when h), it is possible to supply the consumer more or less cold water from pipeline 1 by changing the level of water in the tank from h to N. When level H occurs, the float 10 acts on the electrical contacts 11, which shut off the pump 5. The pressure drop of water in the pipe 4 through the pressure indicator 12 acts on the valve 2, which stops the flow of cold water through pipe 1 to the tray 7.

14

When the water level in the tank 3 is lowered below the level M, the float 10 stops affecting the contacts 11, the latter causes the pump 5 to turn on and the pressure in the pipeline 4 increases, and the indicator 12 under the pressure in the pipeline 4 opens the valve 2 to supply cold water through the pipeline 1 to tray 7.

The proposed method eliminates the need for expensive ion-exchange-type water treatment plants for small industries, for example, in electric-lamp factories, where hot water can be used for showers and heating, as well as for cooling the forms of flash vacuum bulbs and spirals.

Claims (1)

Invention Formula The method of softening water with salts of temporary hardness, including its heating and precipitation of these salts, characterized in that, in order to reduce material and energy costs, water heating is carried out by mixing with recycled hot water in a ratio that ensures the temperature of the mixture above the temperature of the upper limit of precipitation of temporary hardness salts. --zttxl to fwnft9ffu / nf fO