JPH0158287B2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field] The present invention relates to a method for preventing drainage water in a drain pipe for guiding water accumulated on a rooftop to the ground level from freezing. Rather than turning the heater on and off automatically, this method detects changes in outside temperature and the amount of water in the drain pipe, and activates the heater only when the conditions for the water to freeze are met.

[Prior art]

Roof drains are installed on the roofs of buildings to collect rainwater and direct it to the ground, and drainage pipes extend from the roof drains to the ground. The number of drainage pipes ranges from four in a small building to several dozen in a large building. These drainage pipes serve as drainage channels for melted snow during the winter, especially in cold regions, and when the temperature reaches 0°C or lower, they freeze, causing accidents that can damage the waterproof layer on rooftops.

In order to prevent the water in the drain pipe from freezing, it has been known to suspend a long heater in the drain pipe or to wrap it around the outside of the drain pipe.

These antifreeze heaters generally have the following on/off mechanism. First, the heater has a built-in bimetallic thermoswitch to prevent electricity during the summer, and this type is the most common.
This is normally set to turn on when the outside temperature is 5°C and turn off when the outside temperature is 15°C or higher.

The second type has a built-in heater to prevent excessive temperature rise, and is configured to turn on and off at 50 to 70°C.

The third type uses electronic or hydraulic thermoswitches to open and close electromagnetic contactors to control the heater, and is set to turn on and off at around 0°C to 3°C. There is.

All of these antifreeze heaters are sufficient in the sense of melting ice, but they have the disadvantage that they consume an extremely large amount of power because they require electricity for a very long time. This is because with the first type of heater, electricity is turned on when the outside temperature drops below 5°C, but the electricity does not turn off until the temperature rises above 15°C. That is, in cold regions, electricity is applied continuously for about half a year from autumn to spring of the following year, as long as the outside temperature does not exceed 15°C. This is a problem with the sensitivity of bimetals, but currently there is a gap of 10 to 15 degrees Celsius between on and off.

The second type is turned off only when the temperature rises abnormally to prevent accidents, so it is normally continuously energized and consumes the largest amount of power.

The third type has good sensitivity and turns off when the temperature exceeds 3°C, so it is more energy-saving than the two types. However, since it naturally depends only on the temperature, even on a sunny day without snow or rain, if the temperature drops below 0 degrees Celsius, the power will be turned on, resulting in wasted power.

[Purpose of the invention]

The present invention eliminates the drawbacks of the prior art and enables a drain pipe to be constructed that can significantly reduce power consumption by energizing the heater only when there is moisture in the drain pipe and the temperature is below 0°C. The object of the present invention is to provide a method for preventing freezing.

Hereinafter, the configuration of the present invention will be explained in more detail with reference to the drawings.

Figure 1 is a sectional view of the roof drain;
The figure is a plan view of the roof drain.

The roof drain 1 is installed on a slightly lowered part of the rooftop 2, and includes a cylindrical main body 3 having a brim at the top, an annular waterproof layer retainer 4 laminated on the brim, and the center of the waterproof layer retainer 4. It consists of a drain cap 5 that covers the hole, and a drain pipe 6 having approximately the same diameter as the cylindrical portion is fitted below the main body 3. A waterproof layer 7 is laminated on the roof 2, but only a portion of the roof drain 1 is cut out, and the cut is inserted between the roof drain body 3 and the waterproof layer presser 4. Therefore, the main body 3 and the waterproof layer presser 4
There is no contact and there is a gap. The drain cap 5 is provided with several holes 8 in its sloping portion for introducing water. Further, the roof drain 1 is made of metal such as iron, and the waterproof layer 7 is made of an insulator such as synthetic resin.

In the present invention, the long antifreeze heater 9
is passed through the hole 8 of the drain cap 5 and suspended into the drain pipe 6. The other end of the heater 9 is connected to a power source via a switch mechanism.

On the other hand, the roof drain main body 3 is
A drying heater 10 is provided in an annular manner in the gap between the drying heater 10 and the drying heater 10, and is set so as to be energized at all times. Further, a lead wire 11 is connected to the roof drain main body 3 and the waterproof layer holder 4, and set so that the electrical resistance between them can be measured.

Next, the operating status of this device will be explained.

The antifreeze heater 9 is connected to a temperature sensor, has good sensitivity, and is set so that it will not be energized unless the temperature falls below 0°C. The lead wire 11 is connected to an electrical resistance detector, which constantly measures the resistance value between the roof drain body 3 and the waterproof layer retainer 4. If this resistance value does not fall below a predetermined value, the antifreeze heater 9 is activated. It is designed so that no electricity is applied to it.
In other words, the antifreeze heater 9 is set to be energized only when the resistance value between the roof drain body 3 and the waterproof layer presser 4 falls below a predetermined value and the outside temperature falls below 0°C. .

Suppose that the outside temperature is now below 0°C and it is snowing. Then, the snow accumulated on the roof enters the gap between the main body 3 and the waterproof layer retainer 4 as melted snow water, and wets the gap. Then, the electrical resistance between them suddenly decreases, and the antifreeze heater 9 is activated.

Next, assume that the snow has disappeared and the rooftop is now dry. However, water still remains in the gap between the main body 3 and the waterproof layer retainer 4, making it damp. However, since the drying heater 10 is always operating here, when the snowmelt water stops flowing in, it quickly dries this gap and rapidly increases the electrical resistance.As a result, even if the outside temperature drops to 0℃. Even if it is below, the antifreeze heater 9 is turned off.

Next, when the outside temperature is above 0°C and it is raining, the electrical resistance of the gap will be significantly reduced due to the water entering, but since the outside temperature is above 0°C, the heater 9 will be turned off. It remains as it is. what if,
If the outside temperature drops below 0°C, that is, if the water in the drain pipe freezes, the heater 9 is turned on. and,
When the rain stops, no water enters the gap, the remaining water is dried by the drying heater 10, and the electrical resistance increases, so the heater 9 is switched off.

In other words, if the method of the present invention is followed, the heater 9 will be activated only under the condition that the wastewater freezes, that is, when water remains and the temperature is below 0°C, and will be turned off in other cases. It is.

The roof drain used in the present invention can be of any type as long as it is made of metal, has a separate waterproof layer retainer, and has a hole in the drain cap. The anti-freeze heater is preferably a long, flexible heater whose heating element core is covered with silicone rubber and glass fiber, and which is housed in a stainless steel pipe.

The heater for drying is preferably covered with a waterproof layer and has flexibility.

It is preferable that the space between the main body of the roof drain and the waterproof layer holder be insulated, and the portion through which water passes conductive be treated with conductive paint or the like.

〔Effect of the invention〕

Since the present invention is configured as described above, it can exhibit the following excellent effects.

(b) Since it checks both the outside temperature and water detection, and only energizes the heater when conditions are met that the drain pipe will freeze, the running cost is about 1/10th of that of conventional bimetal systems, for example.

(b) By installing a drying heater, the antifreeze heater can be turned off as soon as water stops entering.

(c) Since the device is simple, it can be installed later on the building after construction.

(d) Since it detects water in the gap between the main body of the roof drain and the waterproof layer holder, it is much more accurate than detecting water in the drain pipe or on the roof.

[Brief explanation of drawings]

FIG. 1 is a sectional view of the roof drain, and FIG. 2 is a plan view of the roof drain. 1...Roof drain, 2...Rooftop, 3...Roof drain body, 4...Waterproof layer holder, 5...
Roof drain cap, 6... Drain pipe, 7...
Waterproof layer, 8...hole, 9...antifreeze heater, 1
0...Drying heater, 11...Lead wire.

Claims (1)

[Claims] 1. A method of preventing freezing of a drain pipe connected to the roof drain and extending to the ground by installing a roof drain on the roof, in which a long antifreeze heater is placed in the drain pipe and the waterproof layer of the roof drain is held down. By installing a drying heater between the waterproof layer and the main body and measuring the electrical resistance between the waterproof layer presser and the main body, the presence of water that has entered this gap can be detected and the outside temperature is 0.
A method for preventing freezing of a drain pipe, characterized by energizing an anti-freezing heater only when the temperature is below ℃ and water has entered the gap.