Stench Trap for Waterless Urinal
The present invention concerns a stench trap in a urinal for connection to a sewer system, where the stench trap is of the kind consisting of three interacting pipe elements, namely an outer pipe, a discharge pipe and a level pipe, where the outer pipe constitutes a compartment in which the level pipe is fitted, and where the discharge pipe, which is fixed to a cover, is the pipe retaining sewer stench together with the level pipe, and where the pipe elements may be dismounted for cleaning.
In DK 1999 00087 is indicated a known stench trap of this type, however comprising certain details making it unsuitable in connection with cleaning and by refitting level pipes.
In order to facilitate cleaning of the stench trap according to DK 1999 00087, the inner pipe, the level pipe, can be removed for providing better space for cleaning. When the level pipe is refitted, it is important for the function of the stench trap that the pipe goes as far as it can go in its seat. If the refitting is not correct, problems may arise in connection with the barrier liquid safeguarding that sewer stench is not released, flows out in the sewer, thereby opening for the unwanted stench. Alternatively, wrong mounting may imply that the liquid level in the stench trap according to DK 1999
00087 is lifted and may in the worst case imply that liquid cannot flow out of the stench trap. This faulty mounting is often not discovered by the cleaners by refitting, and is thus only discovered at the next cleaning. This may, of course, result in unwanted events with urinals without stench trap, alternatively clogged urinals from which liquid cannot be drained off to the sewer.
It is the purpose of the invention to provide a stench trap with a solution to the said problem with faulty mounting of the individual parts of the stench trap so that it may clearly be discovered if wrong mounting occurs, and which provides for rapid and easy remedy.
A stench trap according to the invention has a level pipe with a length largely corresponding to the distance from its seat at the bottom of the outer pipe and to the under-
side of the cover, where the upwardly pointing end of the level pipe is provided with an overflow safety device interacting with the cover for relieving incorrect mounting of the level pipe and as indicator of correct/incorrect mounting.
In order to avoid the problem with faulty mounting, the stench trap is made so that the cover lying over the stench trap in co-operation with the level pipe acts as indicator for correct mounting. The upwardly projecting part of the level pipe has the purpose of ensuring that the level pipe is always fitted correctly. If the level pipe is not mounted correctly, i.e. if not pressed completely as far as it can go to its seat, the cover cannot be fitted, or alternatively, the cover will not be able to fall in place in its recess and thereby provide indication of faulty mounting.
The part of the upwardly projecting level pipe corresponding to the distance from the liquid surface and up to the underside of the cover of the stench trap constitutes an overflow function and may be defined as an overflow safety device. Besides safeguarding and maintaining a certain liquid level, this overflow safety device may be used for exerting pressure via the cover on the level pipe, whereby correct refitting is ensured. The cover may thus be used as a pressing plate if the level pipe is mis- mounted and may thus just be pressed in place in its recess.
As mentioned, a stench trap according to the invention has an overflow safety device, which in a preferred variant is formed by level piping being obliquely cut off at the end facing the cover, where the upper end of the level pipe in the correctly mounted state is disposed immediately under the underside of the cover.
A further variant of a stench trap according to the invention may thus be equipped so that the overflow safety device is constituted by the level pipe of the stench trap provided with apertures in the pipe wall at the end facing the cover, where the upper end of the level pipe in the correctly mounted state is disposed immediately under the un- derside of the cover.
With this solution is achieved the same as mentioned above, namely that the stench from the sewer is prevented from being released to the room, as the oblique cut or the
apertures in the pipe wall provides for maintaining the necessary and desired amount of liquid in the stench trap.
In a preferred variant of the stench trap according to the invention, both the total area through which liquid flows out of the level pipe and the ring area between the level pipe and discharge pipe, respectively, are greater than the total area of access apertures in the cover. Hereby is ensured that by flushing with a bucket of water or similar before cleaning, no problems arise such as inadvertent flushing of barrier fluid.
In the following, the invention is described with reference to the drawing, which without being limiting for the invention shows a preferred embodiment of a stench trap according to the invention, where:
Fig. 1 shows a cross-section of a stench trap, Fig. 2 shows an alternative level pipe, and
Fig. 3 shows details around the cover and its contact surface.
Fig. 1 shows a cross-section of a stench trap 2 according to the invention, where the stench trap 2 is integrated in a urinal 4 of the waterless type, and where its component parts are clearly seen. Instead of flushing with water, urinals of the waterless type function by having a barrier liquid 6 with a specific gravity less than water/urine 8 in the stench trap 2. This type of urinals 4 are often used in public toilets, thus saving a lot of water.
In principle, the stench trap 2 consists of three pipes, namely an outer pipe 10, a discharge pipe 12 and a level pipe 14. The outer pipe 10 constitutes the compartment containing barrier liquid 6, 8 and in which the level pipe 14 is mounted. The discharge pipe 12 is fastened to the cover 16 and is the pipe, together with the level pipe 14, preventing the odour from the sewer from penetrating into the room.
By cleaning the stench trap 2, the cover 16 and thereby the discharge pipe 12 is removed. Then the level pipe 14 is removed, and the liquid 6, 8 collected in the stench trap 2 flows out into the sewer. When the level pipe 14 is removed, cleaning may
readily be performed in the stench trap 2, since interfering elements are no longer present in the stench trap 2. When the level pipe 14 is to be mounted again, it is ensured that the sealing means 18 that are to be between the bottom part 20 of the outer pipe and the level pipe 14 are intact and correctly fitted. Then the level pipe 14 is pressed into place in its seat 22 at the bottom 20 of the stench trap 2.
The upper end of the level pipe 14 is here made with an obliquely cut end 24, so that the length of the level pipe 14 largely corresponds to the distance from the bottom of the level pipe seat 22 and up to the underside of the cover 16. The oblique cut 24 has an angle providing for the maintenance of the necessary/desired amount of liquid 6,8 in the stench trap 2.
In Fig. 2 is seen a variant of the level pipe 14, where instead of an obliquely cut end 24 there are apertures 26 in the pipe wall, allowing passage of the necessary amount of liquid 6, 8. This variant has the same height as the level pipe 14 with the oblique end
24.
These two types of level pipes 14 have the property that if they are not mounted correctly, it is clearly seen by the position of the cover 16, which in that case cannot come to rest in its seat 28. Thereby it clearly appears that the level pipe 14 is not correctly mounted. If the cover 14 does not fall into place, one may possibly bring the assembly in order by pressing the cover 16 into place, whereby also the level pipe 14 is pressed into place in its seat 22.
Fig. 3 shows how the cover 16, recesses 30 and the contact surface 28 for the cover 16 are made.
The total area of the recesses 30 in the cover 16 should always be less that the active area allowing liquid 6, 8 to flow out of the level pipe 14 as well as less than the area between level pipe 14 and discharge pipe 12, whereby it is ensured that by flushing with water with a bucket or the like prior to cleaning, no problems, such as inadvertent flushing away of barrier liquid, will arise.