JPS6234263Y2 - - Google Patents

Description

[Detailed description of the invention] This invention is designed to prevent the inside of a protection tube from freezing in winter in extremely cold regions to prevent the water level detection element, such as a float, from being affected by wind and waves when detecting the water level of a reservoir, etc. The present invention relates to an improved antifreeze water level gauge that prevents a float from failing to follow changes in water level.

In general, electric heating is used to prevent freezing in extremely cold regions, but for example, there is a method invented by the inventor of the present invention that is publicly known in Japan. Name of invention: Electric anti-freezing water level gauge Application date: 1972 March 12, 2015 Application number: 1982-031334 Publication number: 1982-126717 (published on October 5th).

The above-mentioned known invention provides an electric antifreeze water level gauge or protection tube made of plastic, in which a required number of skin current heating tubes, which are approximately equal in length to the protection tube, are directly welded vertically to the inner or outer surface of the metal protection tube. In water level gauges that have protective tubes made of materials for which skin current heating tubes cannot be directly welded or are difficult to weld, the required number of tubes on the inside or outside of the protective tube, or both the inside and outside, and the skin current approximately equal to the length of the protective tube. This was an electric antifreeze water level gauge in which the heating tube was configured in the shape of a chestnut cage, and the inner or outer circumferential surface of the heating tube was installed as close as possible to the outer or inner circumferential surface of the protection tube.

However, when the water level fluctuates widely, the electric antifreeze water level gauge naturally requires a longer protective tube, which often exceeds 40 to 50 meters. In such cases, skin current heating tubes are also used to prevent freezing.
It will be over 50m. Installation of existing water level gauges as well as new ones is difficult due to their length and the weight that comes with their length.

The purpose of this invention is to avoid such difficulties and to
Another object of the present invention is to provide a prefabricated antifreeze water level gauge that is highly efficient in preventing freezing.

The antifreeze water level meter of the present invention will be explained below using drawings.

First, a brief explanation of skin current heating tubes includes a series skin current heating tube shown in FIG. 1 and an induced skin current heating tube shown in FIG. 2. In both figures, 1 and 1' are ferromagnetic heat-generating steel pipes and their cross sections are shown, 2 is an insulated wire or cable that is freely passed through the steel pipes, and 3 is an AC power source, which is usually sufficient at commercial frequency. be.

4 and 4' are connection wires, and the connection between the power supply 3, the insulated wire 2, and the steel pipes 1 and 1' is as follows:
are connected in series at terminals 5 and 6, and the second
In the induced skin current heating tube shown in the figure, for the power supply 3, the insulated wire 2 is the primary circuit, the steel pipe is the straight part of 1, 1',
7 bends, both ends of which are connected by a shorting piece 8, forming a secondary induction circuit for the insulated wire 2. Of course, if the steel pipes 1 and 1' are independent straight pipes, the bend 7 becomes a short-circuit piece 7 similar to the short-circuit piece 8.

In such a case, the wall thickness of the steel pipe 1 or 1' is set to t
(cm), the length is l (cm), the inner diameter of the steel pipe is D (cm), and the thickness of the skin representing the equivalent range where the alternating current i flows through the inner skin of the steel pipe is S (cm), then t>2S , l>D D>>S (1) If the current flowing through the steel pipe in Fig. 1 is i, and the primary current in Fig. 2 is i, then , 1' are also generated, and this alternating current i flows only near the inner skin of the steel pipe and does not flow out to the outside of the steel pipe. Here, S (cm) is the resistivity of the steel pipe material, ρ (Ωcm), the frequency (Hz), and the relative magnetic permeability μ (-). Therefore, for steel, ρ = (10 ~ 20) × 10 ⁶
(Ω·cm), μ=500 to 2000, and f=about 60Hz, so S=about 1 mm. Therefore, wall thickness t=2~3mm
Above, if the steel pipe has an inner diameter D = 8 to 25 mm, the current i =
Even at 50 to 200 A, the current does not actually flow out of the steel pipe, so even if metal connections are made to the outside of the steel pipe, there will be no arcing or harm to humans or animals, and the heat generation per meter is 15 ~150W and can be used as a heat generating tube.

In the present invention, the use of the skin current heating tube is similar to the above invention, and the advantages of using the skin current heating tube over other heating elements have been described in detail in the above invention.

Now, in the present invention, the skin current heating tube shown in Figs. 1 and 2 is not directly used, but the primary circuit as shown in Fig.
The insulated wire 2 passes through several sets of secondary circuits made of heat-generating steel tubes that satisfy conditions (1) and (2).

This secondary circuit is shown in Fig. 3 as heating steel pipes 1a and 1.
Short-circuiting pieces 7a, 8a that short-circuit a' and its both ends; 1
b, 1b' and 7b, 8b which short-circuit both ends;...
1d, 1d' and 7d, 8d that short-circuit both ends;
(7b and 8c are shown by cutting the central tube, so they are not shown). It goes without saying that the secondary current i flows only through the inner skins of the heat-generating steel pipes constituting these several sets of independent secondary circuits. Furthermore, although the figure shows a single-phase circuit, it is common knowledge for ordinary electrical engineers that three-phase star-shaped and triangular circuits can also be formed.

Meanwhile, FIG. 4 is a sectional view of a float type water level gauge to which the present invention is applied, and 9 is a protection tube that protects the water level detection element, in the figure a float 11 and its balance weight 12. 15 is a water level converter, and the converted signal indicates the water level or is sent as a signal to others. 10 is pond water whose water level is to be measured, 13 is a water guide hole that guides the pond water into the protection tube, and 14 and 14' are the upper and lower end boxes of the insulated wire 2 of the antifreeze device shown in FIG. The antifreeze device shown in FIG. 5 is not installed. 16 is a lead-in electric wire, and 17 is a quay of the pond that supports the water level gauge. 18 and 19 are ice blocks formed inside the protective tube, and 19' indicates ice blocks formed outside the tube. The ice block 18 changes the weight of the float 11, and 19 means that the ice block adheres to the protection tube 9, and together with the ice block 18, the vertical movement of the float 11 is restricted or inaccurate.

Now, in such a water level gauge, as mentioned above, if the height of the protection tube 9 exceeds 40 to 50 m, the anti-freeze device according to the above-mentioned invention is not only difficult to install, but also difficult to install or repair. In each case, it becomes necessary to remove the roof 20 of the water level gauge shown in FIG.
The present invention provides a water level gauge that eliminates such inconvenience and difficulty.

The present invention will be explained with reference to FIG. In Fig. 5, unit frames 28, 29, 30, 31 shown in Fig. 6 are placed outside the protective tube 9 of the water level gauge shown in Fig. 4.
4 pieces are inserted. These unit frames may be inserted inside the protection tube 9.

Before explaining Fig. 5, let me explain the unit frame in Fig. 6 a little more.
is a sheath tube having a cross-sectional area into which the group of skin current heating tubes shown in FIG. 3 can be inserted from above; it has a rectangular cross-section in the figure, but it may also have a circular cross-section. The upper part of the sheath tubes 21, 22, 23 is 24, and the lower part is 25.
It is fixed by a ring, and constitutes a unit frame as a whole. The rings 24, 25, etc. have holes 26', 27', etc. as illustrated in the figure, but these are used to connect the connecting plates 26, 27 in Fig. 5 for connecting several unit frames together with bolts, etc. It is for fixing.

The sheath tubes shown in FIG. 6 each have a large number of holes 32 for pond water circulation, but when the antifreeze device of the present invention as shown in FIG. It might be better to just look inside. FIG. 5 shows a case where the sheath tube does not have a hole 32.

Now, the assembly of the antifreeze device of the present invention will be explained with reference to FIGS. 4 and 5. First, in Fig. 4, assuming that only the protection pipe 9 is installed, the upper end box 14 and the water level converter 1 are installed.
5. Is the lead-in wire 16 not yet installed?
Suppose it has been removed.

Next, moving to Figure 5, first, unit frame 3
1 is inserted into the protective tube 9, but the height of the unit frame at this time is determined according to the roof 20 in Fig. 4.
This is determined with consideration given to not interfering with insertion, but it goes without saying that other factors such as weight are also taken into consideration.

Next to the unit frame 31, there are connected the units 30, 29, 28 and the connecting plates 26, 27 in this order, which are assembled into one body so that the height of the unit frame 31 is approximately equal to that of the protective tube 9.

Once the unit frame has been assembled, the third
The skin current heating tube group shown in the figure is each sheath tube 2.
1, 22, 23 from above, but at this time, the respective skin current heating tubes 1a, 1a', 1b, 1
The lengths of b', etc. are determined in consideration of the heights of the unit frames 28, 29, etc. The reason for this is that in FIG. 3, the insulated electric wire 2 has already been passed through the assembled skin current heating tube group with only the attachment of the connecting plates 34 and 35 left, and the flexible portion necessary for the insertion is
This is because it is only the portion fixed by the connecting plates 34 and 35 in FIG. 3.

Before each set of skin current heating tubes is inserted into the sheath tube, they are fixed to the connecting plates 35 and 34 in FIG. At the same time, it facilitates insertion.

Now, the skin current heating tube group inserted into the sheath tubes 21, 22, 23 in this manner is connected to the power source 3 at the upper part thereof. In FIG. 5, as an example, three groups of skin current heating tubes are connected in series, but each group may be independently connected to, for example, a three-phase AC power source.

FIG. 5 shows the upper and lower end boxes 14, 1 shown in FIG.
4' is not shown, but if necessary, insulated wire 2
The lower part of the lower end box 14' is connected to the upper connecting wire 4,
4', 4'', 4, etc. are stored in the upper end box 14.

The above example shows a case in which a skin current heating tube is installed over almost the entire height of the protective tube 9 to prevent freezing. However, since freezing occurs mainly near the water surface at a height of about 1 m, the heating that is originally required is only in this area. Just that is fine.

Therefore, if the height of the skin current heating tube group shown in Fig. 3 is set to about 1 m, and if it is possible to move up and down within the sheath tube according to changes in the water level and changes in the immediately frozen part, the power consumption will be reduced. The savings will be large.

In the present invention, this is possible because the skin current heating tube group is not fixed within the sheath tube.

Whether or not to adopt such a device is determined by whether the reduction in power consumption is balanced against the increase in cost due to its mobility.

In the group of skin current heating tubes used in the present invention, as shown in FIGS. 3 and 5, exposed portions of the insulated wires 2 remain in the gaps between adjacent skin heating tubes. Therefore, if dielectric breakdown of the insulated wire 2 occurs in this portion, electrical leakage to the external pond water may occur. In this invention, sheath tubes 21, 22, 23
etc. are connected by metal rings 24, 25, etc., and each unit frame 28, 29, 30, 31, etc. is also connected by metal connecting plates 26, 27, and the skin current heating tube group is also connected by metal connecting plates 34, 35, etc. It is also possible to connect to the ground relay 200 and detect it using the ground relay 200. Furthermore, it is also possible to save power consumption by providing a watertight heat-insulating tube outside the water level gauge of the present invention along its entire height.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of the principle of a series skin current heating tube, Fig. 2 is an explanatory diagram of the principle of an induced skin current heating tube, Fig. 3 is a perspective view for explaining a group of skin current heating tubes, and Fig. 4 is an explanatory diagram of the principle of an induced skin current heating tube. Fig. 5 is an explanatory perspective view of the water level gauge to which the water level gauge is applied, and Fig. 5 is an explanatory perspective view showing the main parts of the present invention, which has two or more unit frames and whose sheath tubes pass through the group of skin current heating tubes shown in Fig. 3. It is a diagram. FIG. 6 is a perspective view of one unit frame. Explanation of numbers, 1, 1'...Ferromagnetic heat generating steel pipe, 2
...Insulated wire or cable, 3...AC power supply,
4, 4', 4'', 4... Connection wire, 5, 6... Connection terminal for steel pipe and wire, 7... Bend, 8... Short circuit piece, 1a, 1a', 1b, 1b', 1c, 1c ',1
d, 1d'...Ferromagnetic heat-generating steel pipe, 7a, 7b, 7
c, 7d...Bend, 8a, 8b, 8c, 8d...
...Short-circuiting piece, 9...Protection tube, 10...Pond water, 11...
... Float, 12 ... Balance weight, 13 ... Water guide hole, 14, 14' ... Upper and lower end boxes of insulated wire 2,
15...Water level converter or water level indicator, 16...Leading wire, 17...Wharf of pond, 18, 19...Ice block formed inside the protection tube, 19'...Ice block outside the tube, 20
... Roof of the water level gauge, 21, 22, 23 ... Sheath pipe with a cross-sectional area that allows the skin current heating tube group to be inserted from above, 24 ... Upper ring of the sheath pipe, 25 ... Lower ring of the sheath pipe, 26, 27...Connecting plate, 26',
27'...Bolt hole, 28, 29, 30, 31...
... Unit frame, 32 ... Sheath pipe hole for pond water circulation,
34, 35...Connecting plate (Fig. 3), 200...Grounding or grounding relay (Fig. 5).

Claims (1)

[Scope of utility model registration request] In a water level gauge with a protection tube 9, this protection tube 9
One or more unit frames (Fig. 6) are assembled and equipped as a part of the protective tube 9 on the inside or outside, or on both the inside and outside sides, and each unit frame (Fig. 6) is equipped with two or more skin current heating tubes. A heating tube group consisting of a set of (Fig. 3)
one or more sheath tubes 21 into which can be inserted,
22, 23, and these sheath tubes have the required number of holes 32.
and when the number of said sheath tubes is two or more, they are arranged in a straight line in the vertical direction, and each set of said heat generating tubes can be inserted into the sheath tube with the insulated electric wire 2 inserted into the heat generating tube. It has length and flexibility, and is integrated by a connecting plate 34, etc., and the height of the heating tube group (Fig. 3) is up to about 1 m, and moves up and down within the sheath pipe according to fluctuations in water level. A prefabricated antifreeze water level gauge that makes it possible to