JP2008241610A - Vapor sampling method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for safely sampling the vapor produced from a boiler for investigating the quality of vapor in the boiler to monitor whether corrosion or scale trouble is produced in a boiler aqueous system or the vapor in the boiler is proper as vapor for directly heating a product. <P>SOLUTION: In the method for sampling the vapor produced in the boiler from the sampling port 6 provided to vapor extracting piping 10 in order investigate the quality of the vapor in the boiler, a pressure gauge 4 is installed out the terminal of the vapor extracting piping 10 and a siphon pipe 2b is provided between the pressure gauge 4 and the sampling port 6. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention examines the steam quality in the boiler, and monitors whether the boiler water system is corroded or scaled and whether it is suitable for direct heating steam for products such as food, gauze and bandages. The present invention relates to a method for safely collecting generated steam.

Conventionally, in order to check whether a boiler is operating in a good state, steam is collected, condensed, and the amount of dissolved oxygen (DO), pH, electrical conductivity, and the like are examined. . In addition, when heating or sterilizing a product to be sterilized, many methods have been adopted in which steam generated in a boiler is introduced into a heat exchanger to indirectly exchange heat with the product. It has become common to heat and sterilize products by blowing directly into the product without using an exchanger.
In food manufacturing plants, in order to maintain the deliciousness and freshness of raw materials as much as possible, steam has been directly blown into foods and sterilized. Under such circumstances, if foreign matter is contained in the steam, the food blown with the steam is not shipped because it cannot maintain the quality and is discarded. Traditionally, well-treated boilers are used, and well-managed boilers are used, so the quality of such steam is rarely an issue, and the quality of the final product is experienced. The person judged by the test and shipped only acceptable products. Such a situation occurs not only in cereals such as corn flakes, but also in manufacturing processes such as retort foods and canned foods, and also occurs in sterilization of gauze and bandages in hospitals.

As long as conventional steam is used as a steam generation source and a controlled boiler is used, the generated steam quality is not a problem. In recent years, however, small once-through boilers that are relatively inexpensive and capable of unattended operation have become widespread. In a small once-through boiler (defined as a special circulation boiler in JIS B 8223), the economy is emphasized and an air / water separator that is not so excellent in performance is provided. There is a tendency to be included. Therefore, in order to use the steam generated in such a small once-through boiler in direct contact with the product, it is necessary to collect the steam generated from the boiler and monitor the quality of the steam.
In addition, in the past, even when using sufficiently treated water and using a well-controlled boiler, in order to prevent foreign matter from entering the steam, Since the steam is discarded and the steam is used after a considerable time has elapsed since the start of operation, the amount of steam discarded is excessively large, resulting in waste of steam. If the quality of the steam can be accurately measured, such waste of steam can be prevented.

In this way, in order to check the operating state of the boiler water system and to monitor the suitability of products such as food, gauze and bandages as direct heating steam, sampling steam generated from the boiler and examining its steam quality ,is important.
Therefore, the applicant of the present application has completed and proposed a device for specifically checking the vapor quality (Patent Document 1).
However, many existing low-pressure plants are rarely provided with a steam collection point, and there is a problem that a steam collection point cannot be newly established during continuous plant operation. Therefore, an existing pressure gauge or the like is removed to provide a steam sampling point, and the steam quality is monitored for an arbitrary period.
In general, a Bourdon tube type pressure gauge is used. The Bourdon tube of a pressure gauge is made by bending a flat tube into an arc shape, fixing one end and closing the other end so that it can move freely, and has a structure in which a toothed fan-shaped piece is engaged with the tip. When this pressure gauge was installed at a position where the steam was in direct contact, the steam entered the Bourdon tube and was heated, resulting in a high temperature, which sometimes did not show the correct value. Therefore, a method is adopted in which a siphon tube is attached in front of the pressure gauge and water is put therein so that steam or high-temperature water does not directly enter the Bourdon tube (use at 80 ° C. or lower).

For the above reasons, the pressure gauges arranged in the existing steam pipes are often attached in the order of “steam header—siphon pipe—valve—pressure gauge”. The reason why the valve is installed in front of the pressure gauge is to facilitate replacement of only the pressure gauge when the pressure gauge breaks down.
When collecting steam from this state, there was no means other than removing only the previous pressure gauge from the valve and collecting steam, and pressure could not be measured simultaneously while collecting steam. For this reason, the actual situation is that the workers always have dangers such as the ejection of steam during the work of installing the steam outlet.
On the other hand, as a device to monitor the corrosion status of the condensate system of the boiler, it is made of a transparent material that has a steam cooler that accepts steam from the boiler and condenses, and a condensate outlet and can be fitted with a test piece inside. There has been disclosed a boiler condensate system monitoring device comprising a test piece column and a pipe for supplying the condensate from the steam cooler to the test piece column (see Patent Document 2). However, even in this technique, Patent Document 1 cited above does not mention any method for collecting steam generated from the boiler.

Japanese Patent Application No. 2005-283870 Japanese Patent No. 3662037

  In such a situation, the present invention checks the steam quality in the boiler, checks the operating state of the boiler water system, and monitors the suitability as steam for direct product heating. The purpose is to provide a method of collection. It is another object of the present invention to provide a method capable of safely collecting steam generated from a boiler, condensing it, and evaluating whether it is suitable as direct heating steam.

As a result of intensive studies to achieve the above object, the present inventor installed a pressure gauge at the end of the steam extraction pipe provided by the sampling port, and a siphon tube between the pressure gauge and the sampling port. By providing this, it was found that the object could be achieved, and the present invention was completed based on this finding.
That is, the present invention
(1) A method for collecting steam generated from a boiler from a sampling port provided in a steam outlet pipe in order to check the steam quality in the boiler, wherein a pressure gauge is installed at the end of the steam outlet pipe, A steam collecting method, characterized by providing a siphon tube between a pressure gauge and the sampling port;
(2) The steam sampling method according to (1) above, wherein a steam take-out pipe is disposed at any of the main steam pipe, the steam header, and the high temperature regenerator inlet,
(3) The steam collected from the sampling port is condensed, the quality of the condensed water is measured, and whether or not the quality of the steam is suitable as steam for directly heating and sterilizing the product is evaluated (1) or ( (4) The steam sampling method according to 2), and (4) the steam collected from the sampling port is condensed, and at least one of the electrical conductivity, pH, TOC, and dissolved oxygen concentration of the condensed water is measured. The steam collecting method according to (2),
Is to provide.

According to the present invention, in order to check the steam quality in the boiler and monitor whether the boiler water system is suitably operated and whether it is suitable as steam for direct heating of products such as food, the steam generated from the boiler is safely A method of collecting can be provided.
In addition, according to the present invention, by condensing the safely collected steam and performing water quality analysis of necessary items, it is determined whether the boiler water system is suitably operated, and whether it is suitable as steam for direct product heating. It is possible to provide a method for evaluating the above. As a result, it is possible to prevent accidents caused by corrosion or scales, or accidents in which poor quality steam is accidentally blown directly into products such as foods to generate defective products.

The steam sampling method of the present invention is a method of sampling steam generated from a boiler from a sampling port provided in the steam outlet piping in order to check the steam quality in the boiler, and a pressure gauge is provided at the end of the steam outlet piping. A siphon tube is provided between the pressure gauge and the sampling port.
In the steam sampling method of the present invention, the location where steam generated from the boiler is collected is not particularly limited, but is preferably collected at any of the main steam piping, the steam header, and the high temperature regenerator inlet.
Next, an example of collecting steam from an existing steam header in which a pressure gauge is installed will be described with reference to the attached drawings.
FIG. 1 is a schematic diagram showing an example of a state in which a pressure gauge is installed in an existing steam header. Normally, the pressure gauge 4 is “steam header 1—siphon tube 2a—valve 3a—pressure gauge 4”. Are installed in this order. In this state, since drain is accumulated in the siphon tube 2a, steam and high-temperature water do not directly enter the Bourdon tube of the pressure gauge 4.

FIG. 2 shows a steam take-out equipped with a sampling port according to the method of the present invention, which is produced using the configuration of “steam header 1—siphon tube 2a—valve 3a—pressure gauge 4” shown in FIG. It is a schematic diagram which shows an example of a structure of piping.
The steam extraction pipe 10 can be produced by the following operation. First, in FIG. 1, the valve 3a is closed and the pressure gauge 4 is removed. Next, in FIG. 2, the cheese 5, the valve 3 b, the sampling port 6, and the siphon pipe 2 b are attached, and the pressure gauge 4 is installed at the end, whereby the steam take-out pipe 10 is produced.
In the steam extraction pipe 10 having the above-described configuration, when the steam is continuously collected from the sampling port 6, the water in which the steam is condensed does not accumulate in the siphon pipe 2 a. On the other hand, in the siphon tube 2b, the pressure gauge 4 is installed at the end, and since steam is not sent, steam condensate accumulates, and the pressure gauge 4 does not directly enter steam or high-temperature water into the Bourdon tube, It won't get hot.
In the present invention, the steam take-out piping is configured as shown in FIG. 2, so that even when a steam collection point is provisionally provided, a pressure gauge can be installed, and to a worker due to steam ejection or the like. The danger of can be avoided.

In the steam sampling method of the present invention, the steam collected from the sampling port is condensed, the quality of the condensed water is measured, and whether or not the quality of the steam is suitable as steam for directly heating and sterilizing the product. It is preferable to evaluate, or it is preferable to measure vapor quality by measuring at least one of the electrical conductivity, pH, TOC, and dissolved oxygen concentration of condensed water. By examining the vapor quality in this way, it is possible to evaluate the presence or absence of a component that hinders the product in the vapor.
The boiler to which the method of the present invention is applied is not particularly limited, and can be applied to special boilers such as round boilers, water tube boilers, small once-through boilers, low pressure boilers, and medium / high pressure boilers.

  In the present invention, one or more items such as dissolved oxygen, pH, electrical conductivity, and organic oxygen (TOC) are measured in accordance with the item to be focused on. When steam is directly blown into products such as foods and beverages for heating and sterilization, the amount of impurities in the steam should be within the water quality standards. Although dissolved oxygen is not listed in the water quality standards for tap water, it is an important item for judging the quality of steam. A large amount of dissolved oxygen in the condensed water means that there is a large amount of oxygen in the steam, so if high-temperature steam with a high oxygen content is blown directly into foods, beverages, etc., the product may deteriorate due to oxidation. There is. Moreover, it may cause corrosion of the steam pipe and may cause an accident such as rust peeled off from the corroded pipe and mixed into the product.

  The pH is measured in order to detect a pH affecting component contained in the vapor. In the water quality standard, 18 kinds of inorganic compounds are individually taken up, and a standard value is set for each. In the method of the present invention, the amount of ions present in the condensed water is comprehensively determined by measuring the electric conductivity of the condensed water. If the electric conductivity is a predetermined value or less, the ionicity in the condensed water is determined. It can be determined that there are few substances and therefore there are also few inorganic impurities in the vapor. If the electrical conductivity of the condensed water increases, the cause of each compound can be investigated and countermeasures can be taken.

  In the water quality standard, 22 kinds of organic compounds are individually taken up, and a standard value is set for each. In the method of the present invention, the amount of organic compound present in the condensed water is comprehensively determined by measuring the organic carbon in the condensed water. It can be determined that there are few compounds, and therefore there are also few organic impurities in the vapor. If the organic carbon in the condensed water rises, the cause of each individual compound can be investigated and measures taken.

In the present invention, items for measuring dissolved oxygen (DO), electrical conductivity, pH, organic carbon (TOC), and the like can be appropriately selected according to the quality of boiler water, the purpose of use of steam, and the like.
According to the present invention, the steam generated from the boiler can be safely collected and the quality of the steam can be examined in this way, and by measuring the electrical conductivity, pH, TOC, dissolved oxygen concentration, etc. of the steam condensed water It can be evaluated whether the steam is suitable as a direct heating steam.

EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited at all by this example.
Example A steam extraction pipe having a sampling port as shown in FIG. 2 was disposed on the steam header of a multi-tube small once-through boiler (manufactured by Samsung). Subsequently, in this small once-through boiler, pressure was applied to a normal pressure of 0.6 to 0.8 MPa, and the state was maintained for one month. As a result, no abnormality was found in the pressure gauge, and it continued to show a normal value. In addition, steam collected from the sampling port was supplied to a water-cooled heat exchanger to obtain condensed water at room temperature.
Therefore, in the method of the present invention, there is no danger, and it is possible to always collect steam under measurement with a normal pressure gauge, and the steam can be easily condensed and used for water quality analysis equipment. I understand that I can do it.

  The steam sampling method of the present invention is used to check the quality of steam in the boiler, to check whether corrosion or scale failure has occurred in the boiler water system, or to monitor the suitability as steam for direct product heating. The generated steam can be collected safely.

It is a schematic diagram which shows an example of the state by which the pressure gauge is installed in the existing steam header. It is a schematic diagram which shows an example of a structure of the vapor | steam extraction piping which attached the sampling port based on the vapor | steam collection method of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Steam header 2a, 2b Siphon tube 3a, 3b Valve 4 Pressure gauge 5 Cheese 6 Sampling port 10 Steam extraction piping

Claims (4)

  In order to check the steam quality in the boiler, the steam generated from the boiler is collected from a sampling port provided in the steam outlet pipe, and a pressure gauge is installed at the end of the steam outlet pipe. A steam sampling method comprising providing a siphon tube between the sampling port.   The steam sampling method according to claim 1, wherein a steam take-out pipe is disposed at any of the main steam pipe, the steam header, and the high temperature regenerator inlet.   3. The steam according to claim 1 or 2, wherein the steam collected from the sampling port is condensed, the quality of the condensed water is measured, and whether or not the quality of the steam is suitable as steam for directly heating and sterilizing the product. Collection method.   The steam sampling method according to claim 1 or 2, wherein the steam collected from the sampling port is condensed and at least one of electrical conductivity, pH, TOC and dissolved oxygen concentration of the condensed water is measured.

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