Baths – closets – sinks – and spittoons – Ventilation – House plumbing
Reexamination Certificate
2002-02-27
2004-02-03
Fetsuga, Robert M. (Department: 3751)
Baths, closets, sinks, and spittoons
Ventilation
House plumbing
C137S512000
Reexamination Certificate
active
06684415
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a ventilation apparatus that supplies a gas to a transportation pipe carrying a liquid, and more specifically to a drain pipe ventilating apparatus that is capable of preventing the breakage of water seal by ventilating a drainage path of a drain pipe, without installing a ventilation pipe such as individual ventilation pipe or a circuit ventilation pipe that has a vent hole at a high position thereof.
DESCRIPTION OF THE BACKGROUND ART
When a liquid (for example, water or waste water) held in a container is allowed to flow down (be drained, for example) in a flash by making use of the difference in height (namely, water head difference or gravity), a pressure in a transportation pipe (for example, a drain pipe) before the liquid passes is different from that pressure after the liquid has passed in case the cross section of the pipe is filled with the liquid in part of the inner space of the transportation pipe. That is, it is well known that, when a plug of liquid passes through the transportation pipe while filling the cross section thereof, a given point in the transportation pipe receives a positive pressure as the plug of liquid approaches that point and a negative pressure as the plug of water moves away from that point. At the given point in the transportation pipe, the positive pressure is generated since the flowing plug of liquid compresses the gas lying ahead before the liquid passes the point, while the negative pressure is created by the empty space created behind the plug of liquid to suck a gas into the empty space after it has passed the point.
At one point in the transportation pipe before a mass of liquid passes, the gas lying ahead of the coming mass of liquid is compressed by such mass and the pressure at that point increases (thus, the positive pressure is generated), and after the liquid has passed, the excessively negative pressure (or reduced pressure) is created (therefore, the pressure in the transportation pipe is lower than in the outside thereof) since the space evacuated by the mass of liquid is not promptly filled with a gas.
Liquid transportation systems of which transportation pipe is subjected to a positive pressure and a negative pressure as described above include a drainage system. Therefore, problems encountered in the drainage system and a ventilation apparatus of the present invention employed in the drainage system as means for solving the problem will be described below as examples. It should be noted, however, that the ventilation apparatus of the present invention is not limited to the application to the drainage systems but can be applied to a system that carries any liquid as long as the system involves a transportation pipe that carries a liquid. The liquid may include solids and/or gas as long as the liquid and the other matters carried by the liquid can be regarded as a fluid as a whole. In the description of the ventilation apparatus of the present invention that follows, liquid will be referred to as “water” or “water or waste water” as a representative thereof. However, the ventilation apparatus of the present invention can be applied to a system that drains a liquid other than water or waste water.
In a drainage system that drains from an apparatus such as a liquid container, in general, a drain pipe serving as a transportation pipe has a water seal portion (or trap, installed therein. When an excessive negative pressure is developed in the drain pipe of the drainage system, a kind of a siphoning phenomenon occurs in the pipe. This decreases a quantity of the sealing water, which leads to the breakage of the water seal (or loss of the sealing water), thus giving rise to such problems as odor escaping from the drain pipe to the outside, or suction sound being heard when draining.
A typical measure to counter this problem will be described below with reference to FIG.
8
.
FIG. 8
schematically shows a drainage system that drains water or waste water held in a container (
12
) through a drain pipe (
13
) by means of difference of elevation. Connected to the drain pipe (
13
) are ventilation pipes (
16
,
17
) at proper positions in the drainage path. When a negative pressure is created in the drain pipe (
13
), air is supplied to the drain pipe (
13
) through the ventilation pipes (
16
,
17
) by means of the atmospheric pressure. Thus the inner pressure of the drain pipe (
13
) is prevented from decreasing excessively.
The ventilation pipes (
16
,
17
) communicate with a ventilation pipe (
19
) that runs vertically along the inner wall of the building. A vent hole of the ventilation pipe (
19
) is installed on the external wall of the building at a high position, and is called a wire cage. The vent hole (
18
) is usually installed on the external wall of the building at such high position in order to prevent water or waste water from overflowing from the ventilation pipe when the drain pipe (
13
) is clogged, and also to discharge odor generated from the waste water in the drain pipe to the outside of the building up in the air.
As other method, Japanese Patent Publication No. 2729353 (Japanese Unexamined Patent Publication No. 8-4071) discloses a ventilation valve for a drain pipe fitted with a vent hole installed indoors at a high position. Configuration of this device will be described below with reference to FIG.
9
.
FIG. 9
shows a ventilation pipe (
20
) provided with a ventilation valve (
21
) that introduces air into the ventilation pipe (
20
) by moving a ball (
23
) upward. The ventilation valve (
21
) prevents odor from escaping to the outside with the ball (
23
) seated on a funnel-shaped valve seat (
22
). In this ventilation valve, the ball cannot properly seat when there is a foreign matter between the ball (
23
) and the valve seat (
22
). Since water may leak to the outside in such a case, it is necessary to installed the vent hole of the ventilation pipe at the high position.
DISCLOSURE OF THE INVENTION
The vent hole is installed at the high position in either of the drainage systems described with references to FIG.
8
and FIG.
9
. Therefore, when installing the drainage system, it is necessary to make holes in the floor, ceiling and wall of the building to run the ventilation pipe therethrough in order to install the vent hole at the high position. This may cause the ventilation pipe to be exposed from the floor surface or the wall surface, which makes an unfavorable appearance, or the vent hole installed on the external wall of the building at the high position may affect the appearance of the building exterior.
In the case of a larger building, since the drain pipe extends over a longer horizontal distance, the ventilation pipe must be connected to the drain pipe at a larger number of points, resulting in the more complicated configuration of the individual ventilation passages and the circuit ventilation passages. This makes it difficult to reduce the period and cost of building construction, since a large quantity of piping materials, working hours and construction expense are required to install the drainage system.
The present invention has been made to solve the problems of the drainage system of the prior art as described above. A major object of the present invention is to provide a drain pipe ventilating apparatus that prevents water seal from being broken by supplying air (or gas) to a drain pipe as required, and has such features as 1) the apparatus is installed onto the drain pipe easily in a limited space; 2) leakage of odor and waste water from the drain pipe is not allowed; and 3) the drain pipe can be ventilated without using a ventilation pipe having a vent hole installed at a high position, namely to provide a compact drain pipe ventilating apparatus. Specifically, a major object of the present invention is to provide a drain pipe ventilating apparatus that can be installed at a position lower than sanitary drainage fittings for drainage (such as wash basin and kitchen sinks) and can be installed indoors instead of the individ
Fetsuga Robert M.
Fildes & Outland, P.C.
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