JPS5941106B2 - Jyohatsushikinetsukoukanki - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Evaporative heat exchangers are used in a wide range of fields as cooling and condensing chemical plant process fluids, condensers for air conditioning refrigerators, lubricating oil coolers, intercoolers for compressors, and aftercoolers.

A typical example of a conventional evaporative heat exchanger will be explained with reference to FIG. 1. Cooling pipes a are regularly arranged inside the heat exchanger, and the liquid or gaseous fluid to be cooled is After entering the cooling pipe a from g and flowing through the cooling section a,
The cooled fluid exits from the outlet and is sent back to the equipment in use.

A water tank d is provided at the bottom of the heat exchanger and always holds water, and this water is pumped up by a pump C and uniformly sprayed onto the cooling pipe a by a water spray nozzle b.

The sprayed water forms a water film on the outer circumferential surface of the cooling pipe a and sequentially falls onto the cooling pipe a below, reaches the water tank d, and is circulated by the pump C again.

On the other hand, cooling air is supplied to the louver f by the blower fan e.
After coming into contact with the water film formed on the outer peripheral surface of the cooling pipe a, it is discharged from above to the outside.

At this time, a part of the water film formed on the outer peripheral surface of the cooling pipe a evaporates, and the fluid to be cooled is cooled by the latent heat of vaporization.

The evaporated moisture is discharged to the outside together with the air sucked in by the blower fan e.

The circulating water of such equipment always contains various hardness components such as calcium and magnesium, so if the wall temperature of cooling pipe a is high, these hardness components may be converted to calcium carbonate etc. during long-term use. It precipitates on the outer surface of the cooling pipe a as scale.

In the case of an evaporative heat exchanger, water evaporates on the cooling pipe a, so the hardness components are concentrated and a large amount of scale is formed.This scale has very poor thermal conductivity, so when the scale is formed, the heat exchange performance deteriorates. significantly reduced.

The biggest factor in the formation of this scale is the temperature of the wall of cooling pipe a, and scale formation is significant when the temperature exceeds 50°C, making it extremely difficult to use an evaporative heat exchanger to cool high-temperature fluids. Met.

The present invention prevents the scale from occurring as described above, ensures good heat exchange performance, and extends the life of the heat exchanger. A dry heat exchange section that cools the fluid by indirect heat exchange with cooling air is provided, and a wet heat exchange section that cools the fluid to be cooled by indirect heat exchange with the cooling liquid is connected to the downstream side of the dry heat exchange section. The gist of the present invention is an evaporative heat exchanger characterized in that air taken in from an air intake port is passed through the dry heat exchange section and then through the wet heat exchange section in this order.

Next, an embodiment of the present invention will be described with reference to FIG. 2. A wet indirect heat exchange section 2 is provided above the interior of the heat exchanger, and a spray nozzle 3 is installed in the upper part of the wet indirect heat exchange section 2. Water accumulated in a water tank 8 at the bottom of the heat exchanger is pumped up by a pump 9, passes through a water spray pipe 4, and is turned into minute water droplets from the spray nozzle 3 to cool the wet indirect heat exchange section 2. Water is sprinkled onto the pipe.

Furthermore, a drift eliminator 5 is provided above the spray nozzle 3, and this serves as a water droplet collector to prevent sprayed small water droplets from being discharged together with the air.

Further, a blower 6 and a fan stack 7 are provided above the heat exchanger.

Furthermore, there are dry indirect heat exchange sections 1 on both sides of the exterior below the heat exchanger.
The fluid to be cooled flows into the fluid to be cooled from two locations 11, and first, the fluid to be cooled flows into the dry indirect heat exchange section 1.
Then, after passing through the wet indirect heat exchange section 2 , the fluid is merged and flows to the cooled fluid outlet 12 .

The air intake looper 10 is provided on the outside of each dry indirect heat exchange section 1.6 In the above, when the blower 6 is rotated, air enters the dry indirect heat exchange section 1 through the looper 10, and first the fluid to be cooled is The temperature is lowered by dry cooling.

Subsequently, the water droplets rise against the flow of the water droplets and absorb heat through the wet indirect heat exchange section 2, and then the water is collected by the drift eliminator 5 and discharged to the outside from the fan stack 7.

At this time, since the temperature of the fluid to be cooled passing through the wet indirect heat exchange section 2 has already been lowered by the dry indirect heat exchange section 1, an increase in the tube wall temperature of the wet indirect heat exchange section 2 is suppressed. The generation of scale can be prevented.

Furthermore, since the dry indirect heat exchange section 1 is located upstream of the wet indirect heat exchange section 2 with respect to the flow of cooling air, there is a gap between the dry indirect heat exchange section 1 and the wet indirect heat exchange section 2. Therefore, the dry indirect heat exchange section 1
This will not cause problems such as corroding the pipes and shortening their lifespan.

Note that the cooling tube used in the dry indirect heat exchange section 1 may be a bare tube, but if a finned tube is used, more effective heat exchange can be performed.

In addition, the dry indirect heat exchange section 1 is effective in cooling high-temperature fluids, and the wet indirect heat exchange section 2 is also excellent in cooling medium and low-temperature fluids, so the overall heat exchange characteristics are very good. .

FIG. 3 shows another embodiment of the present invention, in which the same parts as in FIG. 2 are given the same reference numerals.

In this embodiment, a dry indirect heat exchange section 1 is provided on the outside of the heat exchanger, a wet indirect heat exchange section 2 is provided inside the heat exchanger, and the fluid to be cooled passes through the inside of the dry indirect heat exchange section 1 on the outside. It passes through a post-wet indirect heat exchange section 2.

A spray nozzle 3 is provided above the wet indirect heat exchange section 2 to spray water only onto the wet indirect heat exchange section 2.

Air entering from the air intake looper 10 passes through the dry indirect heat exchange section 1 and then through the wet indirect heat exchange section 2, as in the previous embodiment, and is then discharged from the fan stack 7.

As described above, according to the present invention, the temperature of the high-temperature fluid to be cooled is lowered in the dry indirect heat exchange section and then passed through the wet indirect heat exchange section. The generation of external wall scale can be prevented, and high-temperature fluids can be cooled, which has been difficult in the past.

Furthermore, since the high-temperature fluid and the cooled medium fluid are efficiently cooled by different heat exchange sections each having a cooling method suitable for each temperature range, the entire device can be made compact.

Furthermore, since the cooling air is passed through the dry heat exchange section and then through the wet indirect heat exchange section, it prevents moisture from entering the dry indirect heat exchange section and prevents the problem of shortened life due to corrosion. can do.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an example of a conventional device, FIG. 2 is a longitudinal sectional view of an embodiment of the present invention, and FIG. 3 is a longitudinal sectional view of another embodiment of the invention. DESCRIPTION OF SYMBOLS 1... Dry-wet indirect heat exchange part, 2... Wet indirect heat exchange part, 3... Spray nozzle, 7... Fan stack,
10... Air intake looper, 11... Cooled fluid inlet, 12... Cooled fluid outlet.

Claims (1)

[Claims] 1. A dry heat exchange section for cooling the fluid to be cooled by indirect heat exchange with cooling air is provided on the upstream side of the flow path of the fluid to be cooled, and a dry heat exchange section for cooling the fluid to be cooled by indirect heat exchange with cooling air is provided on the downstream side. An evaporative heat exchanger characterized in that a wet heat exchanger for cooling by indirect exchange is connected, and air taken in from the same air intake is passed through the dry heat exchanger and then the wet heat exchanger in this order. vessel.