US3682141A

US3682141A - Steam generators

Info

Publication number: US3682141A
Application number: US68844A
Authority: US
Inventors: Birger Johan Walther Johansen
Original assignee: BIRTON KLIMA OG KOLETEKNIK
Current assignee: BIRTON KLIMA OG KOLETEKNIK
Priority date: 1970-09-02
Filing date: 1970-09-02
Publication date: 1972-08-08
Anticipated expiration: 1989-08-08

Abstract

A steam generator particularly for producing steam to be supplied to a flow of ventilation air for increasing the humidity thereof, comprising a water container, means for heating the water in the container in order to produce steam, means for supplying water to the container for replacing the water leaving the container as steam, means for intermittently draining off the water from the container so as to empty it for water with high mineral concentration in order to avoid or reduce permanent precipitations, the water inlet opening being spaced from the drain opening of the container and being located so as to cause agitation of the bottom water in the container when water is let thereinto. Preferably the valves are automatically operated in such a manner that the inlet valve is kept open when the draining valve is open whereby the bottom water with its precipitations is agitated during the draining operation.

Description

United States Patent [151 3,682,141 Johansen [4 1 Aug. 8, 1972 [54] STEAM GENERATORS Primary Examiner-Kenneth W. S prague [72] Inventor: Birger Johan Walther Johansen, Amey Cra1g'Antnemand H111 Aarhus, Denmark 7 ABSTRACT [73] Assignee: Birton Klima-og Koleteknlk A/S,

Mariedalsvej/truevej, Brabrand,

A steam generator particularly for producing steam to D enmark be supplied to a flow of ventilation air for increasing the humidity thereof, comprising a water container, [22] Filed: Sept. 2, 1970 means for heating the water in the container in order to produce steam, means for supplying water to the [211 App! 68844 container for replacing the water leaving the container as steam, means for intermittently draining off the [52] US. Cl. ..l22/45l R, l22/382 water from the container so as to empty it for water [51] Int. Cl ..F22d 5/00 with high mineral concentration in order to avoid or [58] Field of Search ..l22/382, 448 R, 451 R, 448, reduce permanent precipitations, the water inlet open- 122/451 ing being spaced from the drain opening of the container and being located so as to cause agitation of the [56] References Cited bottom water in the container when water is let thereinto. Preferably the valves are automatically UNITED STATES PATENTS operated in such a manner that the inlet valve is kept 3 s 12 507 511970 Dixon 122/382 Open when the draining valve is p whereby the l:962:676 6/1934 Albright 122/451 x \veter withits Preeipitetiens is agiteted during the 2,921,564 1/1960 Mattox 122/382 drammg operauo" 3,377,994 4/1968 Home ..l22/382 7 Claims 2 Drawing Figures T /0 /9/ :'i N

l I t Wu 1 1 a f i T- I a 1 5 r in A? 3k 4 g Z0 Z\ I PAYENTEDAUQ 8 I972 3.682.141

INVENTOR.

BIRGER IOHAN WALTHER JOHANSEN BY Cvdm Hntonelti Shawna-1L P A TTORNE Y5 STE GENERATORS The present invention relates to steam generators and more specifically though not exclusively to electric steam boilers for use in connection with air conditioning systems in order to supply steam to a flow of ventilation air and thus increase the humidity of the air. Still more specifically the invention relates to a steam generator comprising a water container having a stem outlet, a water inlet, and means for heating the water in the container in order to produce steam.

In such generators it is necessary to constantly or intermittently supply. water to the container in order to compensate for the water leaving the container as steam, and it is known in the art to control the water supply in an automatic manner corresponding to the water consumption. An associated problem is that with the use of normal calcarious water minerals and impurities will be left in the container which, therefore, requires cleaning from time to time.

It is an object of the present invention to provide a steam generator which may operate in a safe automatical manner with calcarious water.

A more specific object of the invention is to provide a steam generator in which there is provided a special outlet opening for intermittently draining ofi the water from the container so as to generally avoid water with a too high concentration of minerals. During normal operation of the steam generator, when water is continuously or intermittently let into the container for substituting the amount of water leaving the generator as steam, the mineral concentration in the water contents of the container will be steadily increasing because the mineral conetnts of the water does not leave the container together with the steam. Thus, after a while, heavy pricipitations may occur in the container and even affect the operation of the heating means, so it is desirable to empty the container from time to time so as to let out all or almost all water with high mineral contents and let in new water of normal mineral contents.

According to the invention the said inlet pipe is located so as to direct the inlet water generally towards the bottom portion of the container, whilst the said outlet opening is located adjacent the bottom of the container preferably spaced from said inlet opening whereby the water let into the container by normal operation will cause a certain agitation of the bottom water therein, so that precipitations are to at least a considerable degree prevented from falling to rest on the container bottom. When after a while the water is let out, preferably through a large diameter outlet pipe, the water will generally have a mineral contents which is higher than in case of the inlet water being introduced without causing agitation in the bottom water, e.g., if the water is let in vertically up through the bottom and thus generally away from the bottom portion or bottom space of the container.

It is known in the art to provide automatical means for controlling the operation of the inlet valve so as to maintain a generally constant water level in the container, e.g., a water level varying between a certain minimum level and a certain maximum level. According to a special feature of the invention the said control means for the outlet valve are operatively connected additionally with said inlet valve so as to cause said inlet valve to be open during at least a period of the time intervals in which the outlet valve is open. Especially with usually high pressure on the inlet water it will hereby be obtained that the bottom water is violently agitated during the draining off thereof, so that even heavier precipitation pieces already deposited on the container bottom or elsewher will be mixed into the water so as to be able to leave the container together with the water.

In the following the invention is explained in more detail with reference to the accompanying drawing in which:

FIG. 1 is a schematical side view, partly in section, of an embodiment of a steam generator according to the invention, and

FIG. 2 is a top view of the water container thereof.

The steam generator shown comprises a closed water container 2 having a lower water inlet pipe 4 in which there is mounted an electromagnetic valve 6. From the top cover of the container there projects a pair of electrode rods 8 down into the container, and an upper steam outlet pipe 10 extends to a location in which the steam is to be used, e.g., for injection into an air flow in a ventilation duct.

Also located adjacent the container bottom there is provided a thick outlet pipe 12 connected to a drain pipe 14 through an electro magnetic valve 16. An overflow 18 from the container is connected to the drain pipe 14.

In the current feeding cirquit for the electrodes 8 there is inserted an automatical switch device 19 which is connected so as to control the operation of the electromagnetic inlet valve 6 responsive to variation in the current between the electrodes 8. The switch device 19 is so adjusted that it causes the valve to open when the electrode current is as small as corresponding to a certain low water level in the container (level a) and to close when the water reaches a certain higher level (level b). It will be understood that the resulting electrical resistance between the electrodes is highly dependant of the height of the water level, so it is easy to automatically register the current variation in the unit 19. The detailed design of this unit is a matter of ordinary skill and should need no further description in the present connection.

It will be readily understood that with the arrangement shown the switch device 19 will serve to automatically cause a refilling of water into the container every time the water sinks to the level a, so the generator may work constantly in a self controlled manner.

For the operation it is a condition that the water is electrically conducting, i.e., that the water contains minerals or the like. However, this is always the case with water in ordinary water supply systems, and for the same reason the steam production will give rise to considerable precipitation adjacent the container bottom. In order to obtain an automatic rising out of the precipitations the electromagnetic valve is operatively connected with a time switch device 20 which serves to open the valve 16 for a short period with suitable, preferably adjustable time intervals. It is an important feature that the draining pipe system 12, l4, 16 is of large diameter whereby a strong outlet flow is produced so that also larger precipitated material pieces may be rinsed out.

As shown also in FIG. 2 the inlet pipe 4 is connected to the container in an almost tangential position thereto. It is hereby obtained that the precipitations will be agitated every time water is let into the container, whereby the formation of solid deposits on the bottom is to some degree counteracted, since in nonnal operation it is preferred to let the valve 6 open relatively often, e.g., at intervals of 10 seconds to 2 minutes, the opening time being, e.g., few seconds only.

As mentioned, it is a special and important feature of the invention that-as illustrated by an electrical connection 22 between the timer 20 and the inlet valve 6- that the inlet valve 6 is opened concurrently with the opening of the outlet valve 16, i.e. during the rinsing out of the container. Hereby it is ensured that practically all loose precipitations are rinsed out. The rinsing outlet valve 16 may be opened, e.g., two to four times per hour for asteam production corresponding to a consumption of about 5 liters of water per hour. However, the optimal rinsing intervals will be highly dependam of the mineral contents'of the water. The opening time of the valve 16 may be adjusted to, e.g., 5-15 seconds.

When the water has been rinsed out and the valve 16 is closed the valve 6 will remain open until the new water reaches the level b, whereafter the described operation cycles will be repeated.

The invention is not limited to the embodiment shown, since, e.g., the closing of the valve 6 after each period of water introduction may be effected by means of a timer rather than by registration of increased current. The operation intervals of the outlet valve 16 may be controlled by means of a counter registering a predetermined number of operations of the inlet valve 6 and serving to operate the valve 16 every time this number, e.g., 50 refilling operations, has been reached.

In order to obtain an improved agitation effect of the inlet water the inlet pipe 4 from the valve 6 may be substituted by more pipes connected to different inlet openings of the container at desired inlet angles relatively thereto.

What is claimed is:

l. A steam generator comprising:

a water container having a steam opening outlet positioned in the vicinity of the top of said container, a water outlet opening located adjacent the bottom of said container and a water inlet opening;

heating means for heating the water in said containe to produce steam;

a water source for providing water to said container;

an inlet pipe connected between said water source and said water inlet opening, said inlet pipe and said water inlet opening being located so as to direct inlet water generally toward the bottom of,

said container in a manner such that substantially all of the water adjacent said bottom and undissolved impurities contained therein are agitated;

an inlet valve disposed in said inlet pipe adapted to adjust the amount of inlet water supplied to said container in accordance with the volume of water leaving said container as steam;

a drain pipe connected to said water outlet opening;

an automatically operable outlet valve inserted in said drain pipe adapted to adjust the amount of water leaving said container through said drain coliii 'c il rii ans operatively associated with said inlet and outlet valves adapted to intermittently actuate said inlet valve with relatively short time intervals and said outlet valve with relatively long time intervals.

2. A steam generator according to claim 1, in which said inlet opening is located spaced from said outlet opening.

3. A steam generator as claimed in claim 1, in which the cross sectional area of the outlet opening and the drain pipe is at least twice the cross sectional area of the water inlet pipe.

4. A steam generator according to claim 1, in which said inlet valve is automatically operable to open and close said water inlet, whereas said control means for said outlet valve are operatively connected additionally with said inlet valve so as to cause said inlet valve to be open during at least a period of the time intervals in which the outlet valve is open.

5. A steam generator according to claim 1, in which said inlet valve is automatically operable to open and close said water inlet, whereas said control means for said outlet valve are operatively connected additionally with said inlet valve so as to cause said inlet valve to open immediately prior to opening of said outlet valve.

6. A steam generator according to claim 1, in which the water container is an upright cylinder having a circular bottom and the water inlet pipe is connected to the container adjacent the bottom thereof and with an orientation so as to let water into the container substantially tangentially to the inner circumference of the container.

7. A steam generator according to claim 1 wherein said heating means comprise electrodes projecting into the water in said container which are adapted to heat said water by means of a direct current passing therethrough.

Claims

1. A steam generator comprising: a water container having a steam opening outlet positioned in the vicinity of the top of said container, a water outlet opening located adjacent the bottom of said container and a water inlet opening; heating means for heating the water in said container to produce steam; a water source for providing water to said container; an inlet pipe connected between said water source and said water inlet opening, said inlet pipe and said water inlet opening being located so as to direct inlet water generally toward the bottom of said container in a manner such that substantially all of the water adjacent said bottom and undissolved impurities contained therein are agitated; an inlet valve disposed in said inlet pipe adapted to adjust the amount of inlet water supplied to said container in accordance with the volume of water leaving said container as steam; a drain pipe connected to said water outlet opening; an automatically operable outlet valve inserted in said drain pipe adapted to adjust the amount of water leaving said container through said drain pipe; and control means operatively associated with said inlet and outlet valves adapted to intermittently actuate said inlet valve with relatively short time intervals and said outlet valve with relatively long time intervals.