JPS61118641A - Method for pressure proof testing heat exchanger - Google Patents

Abstract

PURPOSE:To facilitate rust inhibiting treatment after a pressure resistance test, by performing the pressure proof test by injecting an aqueous ammonium carbonate solution in a heat exchanger and discharging said aqueous solution after the completion of the test. CONSTITUTION:Blind plates 20, 21 are attached to the barrel side tube stands 4, 5 provided to the barrel of a heat exchanger 1, and a pressure feed pipe 14 and a return pipe 15 are connected to connection ports. Next, a valve 13 is closed while a valve 11 is opened and a pressure feed pump 10 is operated to feed the aqueous ammonium carbonate solution in a tank 9 to the barrel side chambers of the heat exchanger 1 under pressure to perform a pressure proof test. The concn. of the aqueous solution is pref. 1-4wt%. After the completion of the pressure proof test, the valve 13 is opened and a return pump 12 is operated to return the solution in the heat exchanger 1 to the tank 9 and the blind plates 20, 21 are detached to discharge the aqueous solution. Next, blind plates are attached to water chamber side tube stands 6, 7 to perform same operation. By this method, rust inhibiting treatment is also finished.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a pressure test method for heat exchangers that facilitates rust prevention after testing.

(b) Conventional technology Generally, a heat exchanger that has been assembled is injected with hydraulic water and subjected to a pressure test, and then stored for a relatively long period of time before being installed, so it is necessary to perform anti-rust treatment on the inside. As this rust prevention treatment, there is a method in which a water-soluble rust preventive agent is mixed into the hydraulic water to be injected. However, in such a method, the rust prevention effect cannot be obtained unless the injected hydraulic water is discharged and the inside of the heat exchanger is kept full of water even after the pressure test is carried out. Therefore, storing and transporting the heat exchanger is extremely troublesome.

(c) Problems to be Solved by the Invention In order to solve these problems, it has been considered to carry out anti-rust treatment while the hydraulic water is being discharged. One method was to dry the inside of the heat exchanger with hot air after discharging the hydraulic water, and then filling the inside with nitrogen gas or putting a volatile rust preventive agent inside.

For this reason, it takes a lot of energy and time to dry the heat exchanger with hot air. For example, in order to dry a heat exchanger with a shell side internal volume of 8.5 m', electric heating of 80 cm/hour is required to dry a heat exchanger of 230 m
Hot air at °C is blown at a flow rate of 14 rn'/min, and it takes 4 to 5 hours to complete drying. I cut it. In a large heat exchanger, it takes 7 to 8 hours to complete drying. However, when hot air drying was carried out, consideration had to be given to thermal stress in various parts of the heat exchanger, which was troublesome. It's ox.

When filling with nitrogen gas, it is necessary to exhaust the internal air with a vacuum pump and then inject nitrogen gas, and repeat this operation 3 to 4 times to prevent the internal air from mixing with the nitrogen gas. figure.

The work was cumbersome and inefficient.

The present invention was made based on the above circumstances, and its purpose is to provide a pressure resistance test method for a heat exchanger that can easily carry out rust prevention treatment by discharging hydraulic water after a pressure resistance test. There is a particular thing.

b) Means and operation for solving the problems, namely, the present invention includes a process of injecting an aqueous ammonium carbonate solution into a heat exchanger in which a pressure test is performed, a process of conducting a pressure test using the ammonium carbonate aqueous solution as pressure water, This invention provides a method for testing the pressure on one surface of a heat exchanger, which comprises a step of discharging a manual ammonium carbonate aqueous solution after the completion of the pressure test. It is what it is. Therefore, rust prevention treatment can be easily carried out by simply discharging the hydraulic water after the pressure test, making the work easier and more efficient.

(e) Example Above An example of the present invention will be described with reference to FIG. In Figure 1, 1 is a heat exchanger such as a feed water heater that undergoes a pressure test, 2 is its shell, and 3 is an ice chamber. 1 to 1 The memorandum barrel 2 is provided with barrel side nozzles 4 and 5, and the water chamber 3 is still provided with ice chamber side nozzles 6 and 7. ! ,Ta.

Reference numeral 8 denotes an apparatus for carrying out the pressure test method of the present invention, which includes a tank 9 for storing an aqueous ammonium carbonate solution, and a pressure pump 10 for pumping the aqueous solution in the tank 9. Valve 11 provided on the downstream side of this pressure pump 10. Return pump 12 which returns the aqueous solution to tank 9. A valve 13 provided upstream of this return pump 12. Above tank 9. Pressure pump 10.
Pressure feed pipe 14 to which valve 11 is connected. - Tank 9. It is comprised of a return pump 12, a return pipe 15 connecting the valve 13, and the like.

Next, an embodiment of the method of the present invention using such an apparatus will be described. First, for example, the blind plates 20 and 21 are attached to the trunk nozzle 4.5, respectively, and these blind plates 20 and 21 are
The pressure feed pipe 14 and the return pipe 1 are connected to the connection ports provided in the
Connect 5. Next, the valve 13 is closed, the valve 11 is opened, the pressure pump 10 is operated, and the ammonium carbonate aqueous solution in the tank 9 is pumped into the chamber on the shell side of the heat exchanger 1.
This aqueous solution is used as hydraulic water, for example, 45 kg/cn?
Pressurize for 8 hours and perform a pressure test.

The concentration of ammonium carbonate used is from 0.2% to 6% by weight.

A suitable amount for long-term rust prevention is 1 to 4 percent by weight.

This is because if the amount is less than 1% by weight, the rust-preventing power is insufficient, and even if it is more than 4% by weight, the effect of the increased amount cannot be obtained.

Even if steel or cast iron is exposed to an aqueous solution of the above concentration, it will not rust at all.

If the liquid is drained and the container is sealed, the rust prevention effect can be maintained for a considerable period of time. This is because the iron surface becomes passivated by this aqueous solution, but the details of the mechanism are not clear.

After the pressure test is completed, the sloppy valve 13 is opened and the return pump 12 is operated to return the solution in the heat exchanger 1 to the tank 9. Next, the blind plates 20 and 21 are removed to drain the aqueous solution remaining inside. With this operation, the rust prevention treatment of the inner surface of the shell side of the heat exchanger 1 is also completed.

Next, a blind plate is attached to the ice chamber side nozzle stand 6.7, and the pressure feed pipe 14.
Connect the return pipe 15 and perform the same operation as above,
A pressure test and anti-corrosion treatment will also be carried out on this ice chamber 3 side.

However, if you use the traditional heat drying method.

The success or failure of subsequent drying is determined by whether or not the water in the container can be completely drained, so it takes a long time to completely drain the water by rotating the heavy container 19 times. However, according to the method of the present invention, even if there is a small amount of residual water, once the drainage of Daikichi is completed, it will not become an obstacle to rust prevention.

Then, a blind plate was attached to the nozzle stub of the heat exchanger 1 which had been subjected to rust prevention treatment at the same time as the pressure resistance test, and after being stored for 18 months, the inside was inspected, but no rust was observed.

(F) Effects of the Invention - As mentioned in F, the present invention includes a process of injecting an aqueous solution of ammonium carbonate into a heat exchanger for performing a pressure test, a process of conducting a pressure test using the aqueous ammonium carbonate solution as pressure water, and If the ammonium carbonate aqueous solution is discharged after the pressure test is completed, the inner surface of the heat exchanger described in 1) and 2) can be rust-prevented at the same time. Accordingly.

However, the effects are outstanding, such as making pressure testing and rust prevention work easier and more efficient.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of an apparatus used in an embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Heat exchanger, 8... Pressure test device, 9... Tank, 10... Pressure pump, 12... Return pump.

Claims (1)

[Claims] It consists of a process of injecting an aqueous ammonium carbonate solution into the heat exchanger where a pressure test is performed, a process of using this aqueous ammonium carbonate solution as pressure water to conduct a pressure test, and a process of discharging the aqueous ammonium carbonate solution after the completion of the pressure test. A pressure test method for a heat exchanger, characterized in that: