PIPE BEND

Abstract: The invention relates to a pipe bend (1), for a siphon installation (9), formed by two straight pipe parts (2, 3), and a curved pipe part (4) connecting these parts, which pipe bend (1) is provided with means (5) extending from the curved connecting part (4) in one (3) of the pipe parts (2, 3) for guiding a liquid flow (F) in that pipe part (3). The flow guiding means (5) can herein comprise a rib (7) protruding from a side wall (6) of the pipe part (3) and extending at an angle ( beta ) to the centre line (C3) thereof. The invention also relates to a siphon installation (9) provided with such a pipe bend (1), in addition to a liquid discharge system in which such a siphon installation (9) is arranged.

Description: PIPE BEND The invention relates to a pipe bend, in particular for a siphon installation, formed by two pipe parts, the centre lines of which enclose an angle, and a curved pipe part connecting these parts. Such a pipe bend is known and is used for instance in a siphon installation to connect a riser pipe and a fall pipe connecting thereto. The design of the pipe bend is of great importance for the response of a siphon installation, since the siphoning action begins when a liquid in the riser pipe has risen so far that it flows through the pipe bend to the fall pipe and there forms a liquid curtain which covers the whole cross-section of the fall pipe. An underpressure is in that case generated behind the liquid curtain, whereby liquid is drawn up out of the riser pipe, whereafter a new liquid curtain is formed which again generates an underpressure, and so on. In this manner liquid is siphoned out of the riser pipe to the fall pipe. A siphon installation operating according to this principle is described for instance in the European patent specification 0 Oil 778 and is applied particularly in systems for draining waste water from dwellings. The siphon installation is herein intended to guarantee a considerable flow speed in the pipe system, even in the case of relatively small quantities of waste water, whereby a good flushing action is obtained and the risk of deposition and blockage is reduced. The importance of a good design of the siphon installation, and particularly of the pipe bend used therein, is increasing now that the water consumption per household is being pushed back ever further and the quantity of water available in the system for flushing is therefore becoming smaller. The invention therefore has for its object to provide an improved pipe bend which is distinguished from known pipe bends by means extending from the curved connecting part in one of the pipe parts for guiding a liquid flow in the pipe part. By thus guiding the liquid flow a liquid curtain is formed rela- • tively quickly whereby the pipe part is closed off and behind which an underpressure is created which is important for starting a siphoning action. The flow guiding means preferably comprise at least one rib protruding from a side wall of the pipe part and extending at an angle to the centre line thereof . Advantageously the rib even extends transversely of the centre line. The liquid is hereby quickly distributed over the entire cross-section of the pipe part while forming a liquid curtain. Advantageously the rib herein encloses an angle with the centre line of the other pipe part which is larger than the angle enclosed by the two pipe parts . At least the first part of the rib can thus be directed practically parallel to the natural flow of the liquid through the pipe bend. In a preferred embodiment of the pipe bend according to the invention, an element disturbing the liquid flow is arranged in the curved connecting part and the rib is placed in the line of the flow-disturbing element and connected thereto. Such a flow-disturbing element, an example of which is described in applicant's non-prepub- lished Netherlands patent application 1003672, already results per se in an improvement in the response of the siphon installation. By combining this element with a flow-guiding rib according to the present invention a pipe bend is obtained in which a liquid curtain can already be formed with a very small quantity of liquid. The invention further relates to a siphon installa- tion provided with at least one riser pipe inclining in upward direction as seen in the siphoning direction and a downward directed fall pipe connecting thereto, wherein the pipes are connected by a pipe bend as described above and wherein flow guiding means extend in the pipe part connected to the fall pipe. Such a siphon installation has, for the reasons explained above, a very good response . Finally, the invention also relates to a liquid discharge system which is provided with one or more siphon installations as described above. The invention will now be elucidated on the basis of an embodiment, wherein reference is made to the annexed drawing, in which: fig. 1 shows a schematic perspective view of a pipe bend according to the invention, fig. 2 shows a detailed view along arrow II in fig. 1, fig. 3 is a longitudinal section through a siphon installation with a pipe bend according to the invention, and fig. 4 and 5 are longitudinal sections of the siphon installation of fig. 3 in mounted situation, respectively at the beginning of siphoning action and during a siphoning action. A pipe bend 1 (fig. 1) is formed by two, in this case substantially straight pipe parts 2,3, the centre lines C 2 , C 3 of which enclose an angle α, and a curved pipe part 4 connecting these parts 2,3. Pipe bend 1, which is particularly intended for use in a siphon in- stallation, has means 5 for guiding a liquid flow F. These flow guiding means 5 extend from the curved connecting part 4 into pipe part 3 and take the form of a rib 7 protruding from a side wall 6 of pipe part 3 and enclosing an angle β with the centre line C 3 thereof . In the shown embodiment the angle β is practically a right angle. Rib 7 herein encloses an angle γ with the centre line C 2 of the other pipe part 2 (fig. 3) which is larger than the angle a which is enclosed by the two pipe parts 2,3, so that rib 7 extends roughly according to a tangent to the bottom 18 of the curved connecting part 4. The flow F of a liquid is hereby guided over rib 7 along the side wall 6 of pipe part 3 (fig. 2) , wherein the liquid flowing along wall 6 will, as a result of the cohesion, carry along a liquid curtain 12 which closes off the cross-section of pipe part 3. As the liquid flows along wall 6 the flow moreover moves clear of the bottom 18 of curved connecting part 4, so that air can penetrate thereunder as according to arrow A, whereby the process of separation of the liquid flow from the bottom 18 of curved pipe part 4 is reinforced. The result of this flow is therefore that in the case of a comparatively small supply of liquid in curved pipe part 4 a liquid curtain 12 will already be formed which "crosses" pipe part 3 and seals it whereby, when liquid curtain 12 falls downward through pipe part 3, an underpressure will be created therebehind in curved connecting part 4 and pipe part 2, which will result in more liquid being drawn in from pipe part 2 and through connecting part 4, whereby a siphoning action is started. Owing to the specific embodiment of pipe bend 1, this siphoning action is started with a considerably smaller quantity of liquid than when a pipe bend with smooth inner walls is used. Ribs 7 can in principle be arranged on either side of the passage opening of pipe part 3 , but it has been found in practice that a single rib 7 suffices very well. The effect of the flow guiding rib 7 can be further enhanced by arranging in curved connecting part 4 an element 8 disturbing the flow in the manner as described in applicant's earlier, non-prepublished Netherlands patent application 1003672. Rib 7 can herein be placed in line with flow-disturbing element 8 and connected thereto, so that a continuous sharp edge is formed, whereby liquid flow F is carried clear of the bottom 18 of connecting part 4. The pipe bend 1 according to the invention can advantageously be applied in a siphon installation 9 as described in applicant's above stated patent application NL 1003672. Such a siphon installation 9 consists of a collection reservoir 13 which is connected to a pipe 14 through which waste water is supplied and is connected over a riser pipe 10 and a fall pipe 11 to a discharge pipe 16 for further transporting of the waste water. Also arranged herein between fall pipe 11 and discharge pipe 16 is a U-shaped pipe part 15 which functions as liquid seal. Discharge pipe 16 and supply pipe 14 are further mutually connected by means of a vent pipe 17. Siphon installation 9 herein operates to ensure a sufficient flow speed in the discharge system even in the case of relatively small quantities of waste water such as occur when flushing for instance a modern toilet, in order to avoid as far as possible the risk of deposition and blockage. Herein, when reservoir 13 and the riser pipe 10 connected thereto are filled such that the liquid level 19 has reached the highest point of the bottom 18 of pipe bend 1- (fig. 4) , the liquid is guided by rib 7 along the wall 6 of fall pipe 11 while forming a liquid curtain 12 which closes off fall pipe 11. A siphoning action is hereby started in the above described manner which results in reservoir 13 being sucked completely empty (fig. 5) . The waste water is thus transported through the discharge system at relatively high speed, whereby the danger of deposition and blockage is greatly reduced. *****

Claims: CLAIMS 1: Pipe bend (1), in particular for a siphon installation (9), formed by two pipe parts (2,3), the centre lines (C 2 , C 3 ) of which enclose an angle (ex) , and a curved pipe part (4) connecting these parts, characterized by means (5) extending from the curved connecting part (4) in one (3) of the pipe parts (2,3) for guiding a liquid flow (F) in said pipe part (3) . 2. Pipe bend (1) as claimed in claim 1, characterized in that the flow guiding means (5) comprise at least one rib (7) protruding from a side wall (6) of the pipe part (3) and extending at an angle (β) to the centre line (C 3 ) thereof. 3. Pipe bend (1) as claimed in claim 2, characterized in that the rib (7) extends substantially trans- versely of the centre line (C 3 ) of the pipe part (3) . 4. Pipe bend (1) as claimed in claim 2 or 3 , characterized in that the rib (7) encloses an angle (γ) with the centre line (C 2 ) of the other pipe part (2) which is larger than the angle enclosed by the two pipe parts (2,3) . 5. Pipe bend (1) as claimed in any of the claims 2- 4, characterized in that an element (8) disturbing the liquid flow (F) is arranged in the curved connecting part (4) and the rib (7) is placed in the line of the flow- disturbing element (8) and connected thereto. 6. Siphon installation (9) provided with at least one riser pipe (10) inclining in upward direction as seen in the siphoning direction and a downward directed fall pipe (11) connecting thereto, which pipes (10,11) are connected by a pipe bend (1) as claimed in any of the foregoing claims, wherein the flow guiding means (5) extend in the pipe part (3) connected to the fall pipe. 6. Liquid discharge system provided with a siphon installation (9) as claimed in claim 5. *****

Inventors: BENTE CORNELIS WILHELMUS MARIA, BENTE, CORNELIS, WILHELMUS, MARIA
Applicants: BENTE CORNELIS WILHELMUS MARIA, WISA BV, BENTE, CORNELIS, WILHELMUS, MARIA, WISA B.V.
Application year: 1998
Main classification: E03F5
IPC codes: E03F5, F16L43