DE8907085U1 - Drain fitting for cisterns - Google Patents

Description

cistern drain fitting

öThe invention relates to a drain fitting according to the generic term of the independent &Rgr;&bgr;*©&kgr;*&iacgr;^&idigr;.c-p^uchs 1,

Such a drain fitting is known, for example, from the applicant's CH-A-643'622. This has the disadvantage that when flushing is interrupted, the impact of the valve disc on the valve seat creates an annoying noise that is around 10 dB (A) louder than the other noise peaks during flushing.

The invention is based on the object of creating a drain fitting of the type mentioned, which avoids this disadvantage and which is nevertheless functional and can be manufactured inexpensively.

4 « r· ii f « r 4

|j The object is achieved by the invention according to claim 1.

&ggr; _: solves. With the drain fittings according to the invention, the * maximum noise level when interrupting can be reduced by about 10 dB (A) •i>. The noise peak when interrupting the

■-V flushing then only has r^och. approximately the value of the noise ψ peak when the flushing is triggered. A significant mini-

';?' change in the flushing performance during full flushing and partial flushing ω could not be determined. 3In the drain fitting according to the invention, the pressure drop on the lower surface jf of the valve plate shortly before the valve closes is considerably smaller than in known and comparable fittings. In the known fittings, the underside

of the valve plate due to the high flow resistance _shortly before the valve closes there is a large pressure drop and therefore a large pressure difference to the top of the valve plate. The resulting axial force draws the drain fitting so tightly that the loud noise peak mentioned above occurs. In the drain fitting according to the invention, however, the pressure drop in front of the gap or in front of the mouth edge is much lower and the arcial force mentioned is correspondingly smaller.

The noise reduction can be significantly improved if, according to a further development of the invention, the radial distance of the gap to the outer edge of the valve plate is larger

is the radial distance to the inner surface of the valve tube, the flow resistance or the pressure drop at a comparatively large distance to the edge of the valve plate
and the pressure difference between the top and bottom of the valve plate is particularly small shortly before the valve closes.

Through the further developments according to claims 3 to 5, the body on the underside of the valve plate is realized in a structurally simple manner.

An embodiment of the invention is explained in more detail below using the drawing. They show:

Fig. 1 a longitudinal section through the lower part of a

drain fitting attached to the bottom of a cistern, with the valve approximately half closed and

Fig. 2 shows a section corresponding to Fig. 1, but with the valve closed.

The drain fitting has a housing 8 which is provided with a
Threaded nut 11 is attached to the bottom 12 of the cistern and in which in a known manner a not shown here

Float is arranged, which works together with a valve tube 1. The housing has windows 2 for the flow of the rinsing water and an outlet opening 14.

At the lower end of the valve tube 1, a valve plate 3 is attached, which works in a known manner with a valve seat, which is formed by an annular bead 4, which is provided on the top 14 of a flange 13 of the housing 8. The valve tube 1 is connected at its upper end to a flushing actuator (not shown here), with which the valve tube 1 can be raised to initiate the flushing and, if desired, moved back down onto the valve seat against the driving force of the float to interrupt the flushing. The radial distance A between the outer edge 9 of the valve plate 3 and the mouth edge 7 is preferably greater than the radial distance of the mouth edge 7 to the inner surface 20 of the valve tube i. The valve plate 3 can be attached via a holding part 5 or directly to the valve tube 1.

A cylindrical body 6 is mounted on the underside of the valve body 3, which projects into the outlet opening 14 when the valve is closed. The body 6 has a cylindrical outer surface 15, which has a radius that is a few mm, preferably about 1 - 3 mm, smaller than the radius of the outlet opening below the mouth edge 7. In a

Radius of the outlet opening of about 48 mm, the axial extension of the surface 15 is about 5 to 15 mm, preferably about 9 mm.

The following explains how the drain fitting works when the flush is interrupted.

When the valve disk 3 has reached the intermediate position shown in Figure 1, an annular gap 19 forms between the lower edge 18 of the body 6 and the mouth edge 7, in which the flow resistance for the outflowing water becomes increasingly greater, but the pressure drop on the lower surface F ₂ of the valve disk does not increase significantly until the valve closes. The total water pressure on the surface F- and the resulting force P" on the valve disk 3 therefore remains comparatively large and the difference between this force and the opposing force is not significantly greater than the buoyancy force of the float, so that the valve disk does not experience any great acceleration shortly before the valve closes and is moved largely noiselessly into the position shown in Fig. 2.

Claims (5)

&eegr; Q. &pgr;&igr;··,.;"; Q 20040S &igr; - 1 - MG/rü GEBERIT AG 8645 Jona Claims 1. Drain fitting for cisterns, with a valve seat (4) in front of an outlet opening (14) and a valve plate (3) of a valve tube (1) working together with the valve plate, which is to be pulled upwards to open the valve and which can be moved onto the valve seat (4) to interrupt the flushing, characterized in that a body (6) is arranged on the underside of the valve plate (3) which, when the flushing is interrupted shortly before the valve closes, forms a gap (19) with the mouth edge (7) of the drain opening (14), in which the flow resistance is significantly greater than in front of it. 2. Drain fitting according to claim 1, characterized in that the radial distance (A) of the gap (19) to the outer edge (9) of the valve plate (3) is greater than the radial distance to the inner surface (20) of the valve tube (1). 3. Drain fitting according to claim 1 or 2, characterized in that the body (6) has a cylindrical outer surface (15) which, when the valve is closed, projects into the drain opening (14) and is substantially parallel to the surface of this opening (14). 4. Drain fitting according to one of claims 1 to 3, characterized in that the width of the gap (19) in a position in which the lower edge (18) of the body (6) is approximately at the height of the mouth edge (7) is a few mm, preferably approximately 1 - 3 mm. 5. Drain fitting according to claim 4, characterized in that the distance between the lower surface (F ₂ ) of the valve plate (3) and the upper mouth surface (16) in the said position is 5 to 15 mm, preferably about 9 mm. • · ■ t &igr;