Patent Application
20130068855
This invention relates to a mixed stream nozzle for a water treatment apparatus and, more particularly, to a mixed stream nozzle for supplying a mixed stream of raw water and air used for a water treatment apparatus which removes iron, manganese and other soluble elements dissolved in raw water such as underground water by oxidizing and insolubilizing these components without using chemicals such as an oxidizing agent and a coagulant.
As a water treatment apparatus removing iron, manganese and other elements dissolved in raw water such as underground water by oxidizing and insolubilizing these elements with a simple and compact apparatus without using chemicals such as an oxidizing agent and a coagulant, a water treatment apparatus disclosed in Japanese Patent Application Laid-open Publication No. 2002-126768 has been proposed. This water treatment apparatus comprises a mixed stream jet nozzle which is connected at one end thereof to a raw water supply tube for supplying raw water, has an air inlet such as an air inlet tube on the downstream side of the raw water supply connecting portion, and has at the other end thereof a mixed stream outlet for jetting out mixed stream of raw water supplied from the raw water supply tube and air introduced from the air inlet. The mixed stream including multitudes of air bubbles is blown out of the mixed stream outlet and is struck against the water surface above the filter layer disposed below the mixed stream outlet thereby causing vehement aeration both in the water surface above the filter layer and on the surface of the filter layer. By this aeration, soluble substances such as iron and manganese contained in the water are oxidized and thereby are turned to insoluble substances and are caught on the surfaces of particles of the filter material such as filtering sand which constitutes the filter layer either by precipitation or forming flocks. Accordingly, dissolved substances such as iron and manganese in raw water can be turned to insoluble substances and filtered out with a simple and compact apparatus without necessity for using an oxidizing agent or the like.
Describing the function of the mixed stream nozzle more specifically, raw water which has passed this mixed stream nozzle is mixed with air introduced from the air inlet and dissolved oxygen is saturated. Soluble iron monoxide ion in raw water is oxidized by the dissolved oxygen and, as a result, an iron hydroxide ion film is formed on surfaces of the filtering sand. This film acts as a catalyst and accelerates oxidation of the soluble iron monoxide ion and resulting forming of iron (II) hydroxide thereby enhances removal of iron. This iron (II) hydroxide also is deposited on the filtering sand.
There is a problem peculiar to this mixed stream nozzle. That is, iron oxide and other oxides are deposited and solidified on the inner wall of the mixed stream nozzle. More specifically, dissolved oxygen in air which is introduced into raw water from the air inlet of the mixed stream nozzle not only forms iron (II) hydroxide on the filter layer but also oxidizes soluble iron monoxide ion in raw water passing through the mixed stream nozzle and forms iron hydroxide ion film on the inner wall of the mixed stream nozzle. This film acts as a catalyst and causes iron (II) hydroxide to be formed. Since, in this case, the nozzle tube of the mixed stream nozzle is made of stainless steel, the inner wall of the nozzle is not rusted. However, iron (II) hydroxide and other oxides accumulate rapidly on the inner wall of the mixed stream nozzle on the downstream side of the air inlet and this deposit is solidified to form a thick layer and, as a result, blocking of the mixed stream nozzle takes place. Accordingly, in this water treatment apparatus, it becomes necessary to detach the mixed stream nozzle periodically, e.g., every several months, and scrape off the deposit of the hydroxide and oxides by drilling. In case the deposit is seriously high, the inside of the mixed stream nozzle must be rinsed with hydrochloric acid or the like. Water treatment work by the water treatment apparatus must be suspended during this period of deposit removing work resulting in adverse effect on the work efficiency.
The present invention has been made in view of the above described problem in the prior art water treatment apparatus. It is an object of the present invention to provide a mixed stream nozzle which can prevent accumulation and solidifying of iron hydroxide and other oxides on an inner wall of a raw water—air mixed stream nozzle with a simple device and without requiring frequent deposit removing operations.
Repeated studies and experiments by the inventors of the present invention for solving the above described problem have resulted in the finding, which has led to the present invention, that, by utilizing strength of energy of jet stream flowing through the mixed stream nozzle and providing a member which will collide with the mixed stream on the downstream side of an air inlet of the mixed stream nozzle and move by force received from the mixed stream and thereby contact the inner wall of the nozzle, the inner wall of the mixed stream nozzle can be cleaned automatically without requiring any input or power applied from outside.
For achieving the object of the invention, in the first aspect of the invention, there is provided a mixed stream nozzle comprising, at one end thereof, a water supply tube connecting portion which is connected to a water supply tube, an air inlet formed on the downstream side of the water supply tube connecting portion, and a mixed stream outlet provided at the other end of the mixed stream nozzle from which mixed stream of water and air is jetted out characterized in that said mixed stream nozzle further comprises nozzle inner wall cleaning means made of a member which is fixed to an inner wall of the nozzle on the downstream side of the air inlet and extends to the vicinity of the mixed stream outlet for colliding with the mixed stream and moving continuously in the nozzle in a manner to swivel by force received from the mixed stream and thereby contacting the inner wall of the nozzle.
In the second aspect of the invention, the nozzle inner wall cleaning means is a twisted-ring chain.
In the third aspect of the invention, the twisted-ring chain is fixed to diametrically opposite positions of the inner wall of the nozzle by means of a pin inserted through the upper end portion of the twisted-ring chain and suspends from a radially central position of the nozzle.
In the fourth aspect of the invention, a pair of the pin are provided in the longitudinal direction of the nozzle.
In the fifth aspect of the invention, the nozzle inner wall cleaning means comprises a plurality of wires which are attached to a swivel.
In the sixth aspect of the invention, the diameter of the inner wall of the nozzle is larger in a downstream side than in an upstream side and the diameter increases gradually in an intermediate portion from a small diameter portion on the upstream side to a large diameter portion on the downstream side.
According to the first aspect of the invention, by providing the nozzle inner wall cleaning means made of a member which is fixed to an inner wall of the nozzle on the downstream side of the air inlet and extends to the vicinity of the mixed steam outlet for colliding with the mixed stream and moving continuously in the nozzle in a manner to swivel by force received from the mixed stream and thereby contacting the inner wall of the nozzle, cleaning of the inner wall of the mixed stream nozzle can be performed automatically without requiring any input or power applied from outside and, as a result, accumulation and solidifying of iron (II) hydroxide and other oxides on the inner wall on the downstream side of the air inlet of the mixed stream nozzle can be prevented and the work which has been performed frequently in the past for detaching the mixed stream nozzle and removing the oxides can be eliminated whereby the work efficiency of the water treatment apparatus can be significantly improved.
According to the second aspect of the invention, by constructing the nozzle inner wall cleaning means with a twisted-ring chain, a commercially available, inexpensive twisted-ring chain can be used and the object of the invention thereby can be achieved efficiently with a simple device.
According to the third aspect of the invention, since the twisted-ring chain is fixed to diametrically opposite positions of the inner wall of the nozzle by means of a pin inserted through the upper end portion of the twisted-ring chain and suspends from a radially central position of the nozzle, the twisted-ring chain can be fixed to the tube wall with a simple member and can be supported in the central portion of the nozzle whereby smooth movement of the twisted-ring chain can be achieved.
According to the fourth aspect of the invention, a pair of the pin are provided in the longitudinal direction of the nozzle whereby even if the upper side pin which contacts the twisted-ring chain directly owing to friction with the moving twisted-ring chain is cut off due to wear, the twisted-ring chain can be supported by the lower side pin and thereby can be prevented from falling.
According to the fifth aspect of the invention, by constructing the nozzle inner wall cleaning means with a plurality of wires which are attached to a swivel, these wires are swiveled to contact the inner wall of the nozzle and, accordingly, the object of the invention can be achieved with a simple device.
According to the sixth aspect of the invention, since the diameter of the inner wall of the nozzle is larger in a downstream side than in an upstream side and the diameter increases gradually in an intermediate portion from a small diameter portion on the upstream side to a large diameter portion on the downstream side, there is no step in this intermediate portion and, therefore, this intermediate portion can be cleaned with the swiveling nozzle inner wall cleaning means as uniformly as the large diameter portion on the downstream side without likelihood of occurrence of accumulation and solidifying of oxides in the intermediate portion.
Description will now be made about preferred embodiments of the present invention with reference to the accompanying drawings.
Referring to
In the mixed stream nozzle 1, nozzle inner wall cleaning means 10 which is fixed to an inner wall of the nozzle 1 on the downstream side of the air inlet 3 and extends to the vicinity of the mixed steam outlet 4 for colliding with the mixed stream and moving continuously in the nozzle 1 in a manner to swivel by force received from the mixed stream and thereby contacting the inner wall of the nozzle 1 is made of a twisted-ring chain 11 in the present embodiment.
A twisted ring 11a shown in the perspective view of
As a result of numerous experiments, it has been found that the twisted-ring chain is very effective for achieving the object of the invention because the twisted-ring chain can perform swiveling motion continuously and that a normal flat chain which uses a flat oval ring or a circular ring as a unit constituting the chain is not suitable for achieving the object of the invention because the mixed stream does not collide with a flat chain but falls perpendicularly along the flat chain without causing swiveling motion of the flat chain.
A pin 12 of a shape as shown in the perspective view of
The pin 12 is inserted through the twisted-ring chain 11 and the fixing portions 12c, 12c of the pin 12 are inserted in gaps between the tube portion 5 and the joint portion 7 of
Description will now be made about operation of the twisted-ring chain constituting the nozzle inner wall cleaning means.
In the state of use of the mixed stream nozzle 1, raw water supplied from the water supply tube connecting portion 2 and air introduced from the air inlet 3 are mixed together in the joint portion from the air inlet 3 to the vicinity of the fixing portions of the pin 12 and this mixed stream flows down the tube portion 6 as a jet stream containing abundant dissolved oxygen. The mixed stream collides with each of the twisted-rings 11a constituting the twisted-ring chain 11 and thereby moves the twisted-rings 11a by the force of the mixed stream in lateral or slantwise direction. As a result, the twisted-ring chain 11 as a whole is moved in a manner to swivel in one direction (either clockwise or counter clockwise direction). As a result of an experiment in which a transparent vinyl chloride tube is used so that movement in the tube can be visually observed, it has been surprisingly found that this movement of the twisted-ring chain 11 is not a swiveling movement of the foremost end portion (lower end portion) of the chain but a swiveling movement of the chain 11 in its substantially entire length except for a portion in the vicinity of the pin 12. Accordingly, the twisted-ring chain 11 contacts the inner wall of the nozzle in a manner to scrub the inner wall in its substantially entire length of the inner wall where accumulation and solidifying of oxides tend to take place and thereby prevents accumulation of oxides on the inner wall. As a result, accumulation and solidifying of oxides on the inner wall of the nozzle can be prevented as long as the mixed jet stream continues to flow.
In the above described embodiment, a single pin 12 is used for fixing the twisted-ring chain 11 to the inner wall. As a modified example, as shown in
As described above, the diameter of the inner wall of the mixed stream nozzle 1 is larger in the downstream side tube portion 6 than in the upstream side tube portion 5 and the joint portion 7. In the modified embodiment, the diameter increases gradually in an upper end portion 13 of the tube portion 6 which is an intermediate portion from the joint portion 7 which is the small diameter portion on the upstream side to the tube portion 6 which is the large diameter portion on the downstream side and there is no step in this intermediate portion 13 and, therefore, this intermediate portion 13 can be cleaned with the swiveling nozzle inner wall cleaning means as uniformly as the large diameter portion of the tube portion 6 on the downstream side without likelihood of occurrence of accumulation and solidifying of oxides in the intermediate portion 13.
This nozzle inner wall cleaning means 14 comprises a plurality of wires 16 which are attached to a swivel 15. The swivel 15 comprises, as shown in
The operation of this nozzle inner wall cleaning means 14 is similar to the operation of the nozzle inner wall cleaning means 10 of the embodiment shown in
Description has been made above as to the embodiment in which the twisted-ring chain is used and the embodiment in which the radiating wires are used as the nozzle inner wall cleaning means. The nozzle inner wall cleaning means however is not limited to these embodiments but any member may be used regardless of its configuration and material so long as the member is fixed to an inner wall of the nozzle on the downstream side of the air inlet and extends to the vicinity of the mixed steam outlet for colliding with the mixed stream and moving continuously in the nozzle in a manner to swivel by force received from the mixed stream and thereby contacting the inner wall of the nozzle.
A mixed stream jet nozzle of the shape shown in
Underground water was caused to flow through the mixed stream nozzle of the example of the invention and the mixed stream nozzle of the contrast at a flow speed of 10-35 m/second and state of accumulation and solidifying of oxides in the two nozzles was observed. As a result, in the contrast nozzle, blocking of the nozzle occurred due to accumulation and solidifying of oxides and water flowed out of the air inlet after 55 days. In the nozzle of the example, no substantial accumulation of oxides was observed during the same period of time. Upon lapse of 3 months, the experiment was finished and, even at this point, accumulation of oxides on the inner wall was not substantially observed. A small amount of deposit which occurred on the inner wall was not a solidified substance but a soft clayish substance which could be easily washed away by water.
In the example nozzle of the present invention, amount of dissolved oxygen in the mixed stream was not different from that in the contrast nozzle and this amount did not differ between the time of start and time of finish of the experiment. This means that attaching of the nozzle inner wall cleaning means in the nozzle does not influence the amount of dissolved oxygen in any way.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2010--98586 | Apr 2010 | JP | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/JP2011/058188 | 3/31/2011 | WO | 00 | 9/7/2012 |
