WATER TREATMENT METHOD AS WELL AS EQUIPMENT AND CHEMICAL BRIQUET USED IN THE PROCESS

Abstract: The objective of the invention is a water treatment method used to protect from corrosion the water circulation pipework (12) installed in buildings and corresponding, the branch circulation accommodated in the method, and the dosing apparatus (1) being part of the branch circulation, as well as the briquettes (8) containing the relevant chemicals used in the method, which briquettes comprise essentially 40-75 weight fractions of sodium nitrite, 5-25 weight fractions of benzotriazole, 8-18 weight fractions of sodium tetraborate and 5-15 weight fractions of sodium benzoate. The invention relates also to the method of producing said briquettes.

Description: WATER TREATMENT METHOD AS WELL AS EQUIPMENT AND CHEMICAL BRIQUET USED IN THE PROCESS The objective of the invention is a water treatment method used to protect from corrosion the water circulation pipework installed in buildings and corresponding, the branch circulation accommodated in the method, and the dosing apparatus being part of the branch circulation, as well as the relevant briquets containing chemicals used in the method. Corrosion caused by water, sedimentation phenomena and biological growth weaken the functioning of the circulation water systems, increase the operating and maintenance costs, shorten the operating life and might cause sudden damages to be repaired. A proper water treatment - using e.g. corrosion inhibitors - prevents the damages. Damages i.e. corrosion in the pipework and heat exchangers of closed heating water circulations have already for decades been prevented by adding water treatment chemicals to the back water. These are added to the hot-water circulation as liquid concentrates. Because the adding is made in one batch, a sample of the circulating water has to be taken at certain intervals and the chemical contents contained in it has to be analyzed in a laboratory. hen the contents of one or several chemicals are below the level protecting from corrosion, a new concentration has to be added to the water circulation, the quantity of which must be calculated separately based on analytical data, the concentration and the water circulation volume. Another known method of preventing damages and corrosion is the use of an expensive feedback analyzer which controls a liquid chemical dosing pump. The method is generally used in big industrial closed water circulations. The corrosion prevention implemented in the above mentioned traditional way requires regular visits of the chemical supplier to pump the chemicals to the piping or dose the liquid through the expansion tank into the system. In automatic chemical feeding systems the functioning of the corrosion prevention is on the responsibility of the che i- cal and equipment suppliers and requires visits to the premises. All these measures increase considerably the service and maintenance costs of the real estate. The objective of the subject invention is to offer a total solution considering the above mentioned disadvantages and also especially the fact that the water led to the closed system is individual, which means that the purity grade of the water and the amount of chemicals in the water vary. Therefore the solution according to the invention aims primarily at a technically easy dosing of the chemicals and secondly at monitoring the effect of the dosing. The invention relates to a method of water treatment in a closed water circulation system. The method is character- ized in that part of the water in the water system is made to flow through a dosing device fixed installed in the pipe and forming an own branch circulation and back into the water circulation system, and that a briquet is used in the dosing device. The subject invention relates also to the briquet used in the water treatment, which is characterized in that it comprises essentially 40 - 75 weight fractions of sodium nitrite, 5 - 25 weight fractions of benzotriazole, 8 - 18 weight fractions of sodium tetraborate and 5 - 15 weight fractions of sodium benzoate. The invention relates also to the method of manufacturing the above mentioned briquet. The method is characterized in that the components in powder form are combined, pulverized and homogenized in a mill for 1 - 30 minutes, whereafter the obtained mixture is compressed in a mould, at a compres- sion of 5000 - 20000 kPa for 1-15 seconds, and the formed briquet is retrieved. The components used in the briquet according to the inven- tion are as such known compounds also in the water treatment field. The sodium nitrite and the benzotriazole are e.g. well known corrosion inhibitors. Now has however surprisingly been observed that when mixing said components in these dried weight proportions to a mixture and co - pressing the mixture into briquets, considerable advantages are achieved. Compared with traditional water treatment methods, the use of briquets according to the invention enables in addition to an effective corrosion prevention also a more exact and economical dosing. The briquet is moreover non-toxic and simple to use. The briquet according to the invention comprises preferably 50-65 weight fractions of sodium nitrite, 10-20 weight fractions of benzotriazole, 10-15 weight fractions of sodium tetraborate and 8-13 weight fractions of sodium benzoate . Especially preferably the briquet according to the invention comprises 60,7 weight fractions of sodium nitrite, 17,9 weight fractions of benzotriazole, 10,7 weight fractions of sodium tetraborate and 10,7 weight fractions of sodium benzoate. The weight of the briquet is preferably 5- 50 g and has preferably the shape of a cylindrical tablet. A preferable tablet has a diameter of 15-40 mm, a height of 10-35 mm and its edges are sloped in a 45° angle. The pulverization and homogenization of the components according to the subject invention are preferably made in a commercial IKA-Werk A-10 mill or in a ceramic mill using ceramic balls or in a steel mill using steel balls or steel bars. In one preferable form of embodiment the components are combined, pulverized and homogenized in the mill for 10-20 minutes, whereafter the obtained mixture is compressed in the mould at a compression of 7500-15000 kPa for 5-15 seconds. The compression is preferably performed in a mould producing a tablet having an edge angle of 45° . By using the briquet according to the invention, the corrosion prevention technique utilized by big units can be implemented also in small water circulations at a low cost. When using the briquet according to the invention and a suitable dosing device, the separate visits of the chemical supplier to the premises become uncalled for, as the briquets in the dosing device can easily be added. An inexpensive test strip is available to establish the need for change . The enclosed drawing shows a preferable dosing device for the briquet according to the invention. In the drawing fig. 1 shows a side view of the dosing device fig. 2 shows a cutting along the cutting line II-II of fig. 1, and fig. 3 shows an exploded and cross section view of the dosing device and the dosing device connected to the pipework. The dosing device comprises the installation part 1 having two connection pipes 2, 3, both provided with a closing valve 4, 5, and a cover part having the shape of a cartridge 6, inside which is the space 7 for the briquet 8 according to the invention. In the figure the connection pipes 2, 3 are indicated to have identical diameters. The cartridge 6 is with the threads 9 detachably fixed to the corresponding threads 10 of the installation part 1. A gasket 11 is provided between the cartridge 6 and the installation part 1 to seal said parts to each other. The function of the dosing device is here presented installed to the heating water circulation pipe 12 of small houses . The installation part 1 is connected to the water circulation pipe 12 on the go-side of the pump (not shown) by welding the fluid inlet and outlet pipe 2 and 3 of the installation part to the pipe in the direction of the same. The installation part 1 is symmetrical in relation to its longitudinal axis, wherefore the connection can be made both ways . Inside the cartridge 6 is used the briquet according to the invention which slowly dissolves in the circulation water 14. The inlet and outlet pipes 2 and 3 can be separately closed from the flow with their valves 4, 5. The valves 4, 5 are closed when the cartridge 6 is changed and open when the dosing device 1 is in function. A stationary flow is achieved with an incompressible liquid in a circular straight pipe. The bottom construction of the cartridge 6 is designed to provide such flow properties of the heating water which are optimal for the dissolution of the chemicals. The area of the bottom 13 is bigger than the total cross-sectional area of the pipes 2, 3. Based on the above prerequisites the briquet 8 according to the invention dissolves slowly into the water. The chemical concentration of the solution in the cartridge 6 space 7 is higher than the one in the inlet pipe 2 and in the water circulation to be protected. The passive dosing is based on the concentration difference of the chemicals. As the cartridge 6 is fixed with threads 9, 10 to the installation part 1, its content or the whole cartridge is easy to change . The above described dosing device enables the dosing of the water treatment chemicals of the briquet according to the invention to be continuous without separate laboratory analysis of the water sample. With the strip test performed on site can easily be established when the concentration of the chemicals dissolved from the cartridge 6 are at safety limits and new briquets should be added. The subject water treatment method can preferably be used in row houses and in one-family houses having water central heating. Other objects are small apartment houses and also the industry having a big amount of small 0,2 - 6 3 heating or cooling water circulations. The invention is illustrated by the following examples: Example 1 A briquet was produced having the following composition: Sodium nitrite 40 weight fractions Benzotriazole 5 weight fractions Sodium tetraborate 8 weight fractions Sodium benzoate 5 weight fractions. The components were put in powder form into a steel mill (volume 0,3 m 3 ) in which steel balls were used, and the components were pulverized and homogenized for 5 minutes. The obtained mixture was compressed for 1 second in a mould into a briquet at a compression of 5000 kPa . The weight of the briquet was 5 g. Example 2 : A briquet was produced having the following composition: Sodium nitrite 50 weight fractions Benzotriazole 10 weight fractions Sodium tetraborate 10 weight fractions Sodium benzoate 8 weight fractions. The components were put in powder form into a ceramic mill (volume 0,1 m 3 ) in which ceramic balls were used, and the components were pulverized and homogenized for 10 minutes. The obtained mixture was compressed for 10 seconds in a mould at a compression of 10000 kPa, which produced a tablet shaped briquet with a diameter of 20 mm, height of 15 mm and edge angels of 45°. The weight of the briquet was 20 g. Example 3 : A briquet was produced having the following composition: Sodium nitrite 60,7 weight fractions Benzotriazole 17,9 weight fractions Sodium tetraborate 10,7 weight fractions Sodium benzoate 10,7 weight fractions. The components were put in powder form into a mill (IKA- Werk A.10) in which the components were pulverized and homogenized for 1,5 minutes. The obtained mixture was compressed for 15 seconds in a mould at a compression of 15000 kPa, which produced a tablet shaped briquet with a diameter of 33 mm, height of 23 mm and edge angels of 45°. The weight of the briquet was 28 g. One such briquet is sufficient to prevent corrosion of iron, steel and copper in a 10 liter closed water circulation. Example 4 : A briquet was produced having the following composition: Sodium nitrite 75 weight fractions Benzotriazole 25 weight fractions Sodium tetraborate 18 weight fractions Sodium benzoate 15 weight fractions. The components were put in powder form into a steel mill (volume 0,3 m 3 ) in which were used steel bars, and the components were pulverized and homogenized for 25 minutes The obtained mixture was compressed into briquets for 5 seconds in a mould at a compression of 20000 kPa . The weight of the briquet was 45 g.

Claims: CLAIMS 1. A method of protecting from corrosion closed water circulation pipework installed in buildings and correspon- ding, characterized in that at least part of the water in the water system is made to circulate through a branch circulation installed in the system, a dosing device that can be opened and closed from the outside is installed as part of the branch circulation, the relevant chemicals are fed to the dosing device in the form of solid briquets, and the briquets fed contain in optimal mutual proportion all or at least essentially all chemicals used in corrosion prevention of closed water distribution systems. 2. A chemical briquet used in the corrosion prevention of a closed water distribution system, characterized in that it comprises essentially 40 - 75 weight fractions of sodium nitrite, 5 - 25 weight fractions of benzotriazole, 8 - 18 weight fractions of sodium tetraborate and 5 - 15 weight fractions of sodium benzoate. 3. A briquet according to claim 2, characterized in that it comprises 50 - 65 weight fractions of sodium nitrite, 10 - 20 weight fractions of benzotriazole, 10 - 15 weight fractions of sodium tetraborate and 8 - 13 weight fractions of sodium benzoate . 4. A briquet according to claim 2, characterized in that it comprises 60,7 weight fractions of sodium nitrite, 17,9 weight fractions of benzotriazole, 10,7 weight fractions of sodium tetraborate and 10,7 weight fractions of sodium benzoate . 5. A briquet according to one of the claims 2 3, charac- terized in that its weight is 5 - 50 g. 6. A briquet according to one of the claims 2 - 4, characterized in that it has the shape of a tablet . 7. A briquet according claim 5, characterized in that the diameter of the tablet is 15 - 40 mm, its height 10 - 35 mm and the edges are sloped in a 45° angle. 8. A method for producing a briquet according to one of the claims 2 - 4, characterized in that the components in powder form are combined, pulverized and homogenized in a mill for 1 - 30 minutes, whereafter the obtained mixture is compressed in a mould at a compression of 5000 - 20000 kPa for 1-15 seconds, and the formed briquet is retrieved. 9. A method according to claim 8, characterized in that the pulverization and the homogenization is performed in a ceramic mill using ceramic balls. 10. A method according to claim 8, characterized in that the pulverization and the homogenization is performed in a steel mill using steel balls or steel bars. 11. A method according to one of the claims 8 - 10, characterized in that the components are combined, pulverized and homogenized in a mill for 10 - 20 minutes, whereafter the obtained mixture is compressed in a mould at a compression of 7500 - 15000 kPa for 5 - 15 seconds, and the formed briquet is retrieved. 12. A method according to one of the claims 8 - 11, characterized in that the compression is made in a mould producing a tablet having edge angles of 45° .

Inventors: KAPANEN JAAKKO, KAPANEN, JAAKKO
Applicants: KAPANEN JAAKKO, KAPANEN, JAAKKO
Application year: 1997
Main classification: C23F11
IPC codes: C23F11