EP0450955B1

EP0450955B1 - Method for the automatic flushing of a urinal

Info

Publication number: EP0450955B1
Application number: EP91302971A
Authority: EP
Inventors: Takashi Yasuo
Original assignee: Inax Corp
Current assignee: Inax Corp
Priority date: 1990-04-05
Filing date: 1991-04-04
Publication date: 1992-11-04
Anticipated expiration: 2011-04-04
Also published as: EP0450955A1; KR910018645A; ES2036421T3; DE69100008T2; DE69100008D1; JPH03290536A

Description

This invention relates to a method for the automatic flushing of a urinal. More particularly, it is an improvement in the method for the automatic flushing of a urinal which includes preliminary flushing and main flushing.
An apparatus which flushes a urinal with water automatically after its use is widely used (see eg GB-A-1 170 775). The apparatus is based on a known method which includes preliminary flushing and main flushing (hereinafter referred to simply as flushing in contrast to preliminary flushing). If a man stands in front of a urinal, water is supplied into a bowl defining the urinal for a brief period of time to wet its inner surface (preliminary flushing), and as soon as he leaves the urinal, water is supplied into it for a longer period of time to cleanse it fully (flushing). The wetting of the bowl surface by preliminary flushing makes it possible to prevent virtually any urine from contacting the bowl surface directly and contaminating it.
It is an object of this invention to provide a method for the automatic flushing of a urinal which makes it possible to save flushing water.
It is another object of this invention to provide a method which enables a satisfactory automatic cleansing of a urinal by a regular cycle of preliminary and main flushing for anybody who is about to use it after the passage of a predetermined length of time following its preceding use.
This invention is an improvement in the method for the automatic flushing of a urinal which includes a short time of preliminary flushing taking place as soon as a user stands in front of the urinal, and a long time of main flushing taking place as soon as the user has left it, and is characterized by discontinuing flushing, omitting preliminary flushing and then main flushing taking place again as soon as the user has left, if anybody stands in front of the urinal during its main flushing.
The discontinuation of flushing and the omission of preliminary flushing make it possible to prevent the waste of water.
An embodiment of the invention will now be described by way of example only and with reference to the accompanying drawings, in which:

FIGURE 1 is a schematic representation of a urinal and a flushing apparatus which can be employed to carry out the method of this invention;
FIGURE 2 is a chart illustrating a program employed for controlling the operation of the apparatus; and
FIGURE 3 contains two timing charts for two different modes, respectively, of flushing operation.

Referring first to FIGURE 1, there is schematically shown an apparatus which can be employed for carrying out a method embodying this invention. The apparatus includes a water supply pipe 44 extending from a source of water supply, a water supply control device 46 to which the pipe 44 is connected, and a water supply pipe 48 connected between the water supply control device 46 and a urinal 42 mounted on a wall 40. The water supply control device 46 includes a sensor 50 for detecting a man standing in front of the urinal 42, a control circuit 52 to which a signal is inputted from the sensor 50, and an electromagnetic valve 54 connected between the water supply pipes 44 and 48. The control circuit 52 includes a microcomputer in which a control program as shown in FIGURE 2 is stored.
The control program will now be described with reference to FIGURE 2. The program is started if a power source switch is turned on. Step 1 is intended for detecting by the sensor 50 anybody who has come to stand in front of the urinal 42. The program remains at Step 1 until somebody is detected by the sensor 50. As soon as any-body is detected by the sensor 50, the program proceeds from Step 1 to Step 2, at which the valve 54 is opened to start supplying water to the urinal 42, while at the same time, a timer T_i is started to count a predetermined length of time T₁. The program proceeds to Step 3 for checking if the time T₁ has passed. If the time T₁ has not yet passed, the program proceeds from Step 3 to Step 4 for checking if the sensor 50 still indicates the presence of somebody in front of the urinal 42. If somebody is still present in front of the urinal 42, the program returns from Step 4 to Step 3. The program is repeated between Steps 3 and 4 until the time T₁ passes, as long as somebody stays in front of the urinal 42. When the time T₁ has passed, the program proceeds from Step 3 to Step 5, at which the valve 54 is closed to stop the supply of water to the urinal 42, whereupon the preliminary flushing of the urinal 42 is completed. If the person who has been staying in front of the urinal 42 leaves it before its preliminary flushing is completed, the program proceeds from Step 4 to Step 6, at which the valve 54 is closed to complete the preliminary flushing, and the program returns to Step 1.
The program proceeds from Step 5 to Step 7 for checking if somebody is still present in front of the urinal 42. The program remains at Step 7 until he leaves the urinal 42. When he has eventually left the urinal 42, the program proceeds from Step 7 to Step 8, at which the valve 54 is opened again to start supplying water to the urinal 42 to start its flushing (main or full-scale flush-ing), while at the same time, a timer T₂ is started to count another predetermined length of time T₂. The program proceeds to Step 9 for checking if the time T₂ has passed. If the time T₂ has not yet passed, the program proceeds from Step 9 to Step 10 for checking if another person is present in front of the urinal 42. If not, the program is repeated between Steps 9 and 10 until the time T₂ passes. When the time T₂ has passed, the program proceeds from Step 9 to Step 11, at which the valve 54 is closed to finish the flushing of the urinal 42. Then, the program returns to Step 1.
If somebody is detected in front of the urinal 42 during its flushing, however, the program proceeds from Step 10 to Step 12, at which the valve 54 is closed to discontinue its flushing. The program returns from Step 12 to Step 7 so that the urinal 42 may be flushed anew after he has left it.
The time T₁ is preferably from one to four seconds, and the time T₂ from four to 10 seconds.
Attention is now directed to FIGURE 3 showing two modes of valve operation which enable two modes, respectively, of flushing according to the method of this invention as hereinabove described with reference to FIGURE 2. The upper chart, or case 1 represents a basic or normal cycle of flushing which is followed when nobody is detected in front of the urinal 42 during its flushing. This cycle consists of preliminary flushing which occurs as soon as somebody stands in front of the urinal 42, and flushing which occurs when he has left it.
The lower chart, or case 2 represents a modified cycle of flushing which takes place if somebody is detected in front of the urinal 42 during its flushing. In this case, the flushing of the urinal is discontinued, and no preliminary flushing thereof occurs. Therefore, the volume of water is decreased by an amount corresponding to the area indicated by hatched lines in Fig. 3, case (2).
Thus, the method of this invention including the modified cycle of flushing as defined in the appended claims contributes greatly to saving water for flushing the urinal.

Claims

A method for the automatic flushing of a urinal (42) including preliminary flushing which takes place as soon as a user is detected in front of the urinal (42), and main flushing which takes place as soon as the user has left the urinal (42), characterised in that if a user is detected in front of the urinal (42) during its main flushing, said main flushing is discontinued, the preliminary flushing of the urinal (42) is omitted, and main flushing takes place again as soon as the user has left the urinal (42).
A method as claimed in claim 1 wherein said preliminary flushing is from 1 to 4 seconds.
A method as claimed in claim 1 or 2 wherein said main flushing when not discontinued is from 4 to 10 seconds.
A method of operating an apparatus for flushing a urinal (42) automatically, which apparatus includes a sensor (50) for detecting a person in front of said urinal, a valve (54) for controlling the supply of water to said urinal (42), and means for opening and closing said valve (54) in response to a signal from said sensor (50), said method comprising the steps of:
(1) Holding said apparatus in a standby condition until somebody is detected in front of said urinal (42) by said sensor (50);

(2) Causing said valve (54) to open, and a first timer to start timing a first predetermined length of time T₁, as soon as somebody is detected at (1);
and characterised in that said method further comprises the steps of:

(3) Checking if said first timer has finished timing said time T₁;

(4) If the result of said checking is in the negative, checking if somebody is detected by said sensor (50), and if the result of said detection is in the affirmative, returning to said step (3);

(5) Causing said valve (54) to close if the result of said checking at (3) is in the affirmative;

(6) Causing said valve (54) to close and returning to said step (1), if the result of said detection at (4) is in the negative;

(7) If the sensor (50) continues to detect somebody after said step (5), keeping said valve (54) closed until said sensor (50) ceases to detect anybody;

(8) Causing said valve (54) to open, and a second timer to start timing a second predetermined length of time T₂, if said sensor (50) has ceased to detect anybody;

(9) Checking if said second timer has finished timing said time T₂;

(10) If the result of said checking at (9) is in the negative, checking if somebody is detected by said sensor (50), and if the result of said last-mentioned detection is in the negative, returning to step (9);

(11) Causing said valve (54) to close and returning to said step (1), if the result of said checking at (9) is in the affirmative; and

(12) Causing said valve (54) to close and returning to said step (7), if the result of said detection at (10) is in the affirmative.
A method as set forth in claim 4, wherein said time T₁ is from one to four seconds.
A method as set forth in claim 4 or 5 wherein said time T₂ is from four to 10 seconds.