Shower drain system and a shower or shower cabin

Abstract

A shower drain system for recovering thermal energy from a flow of shower greywater comprises: a drain cup for receiving shower greywater, and a heat exchanger arranged downstream of the drain cup, the heat exchanger being configured to heat a flow of incoming cold water with the shower greywater, wherein the drain cup comprises a nozzle arranged and configured to supply hot water into the drain cup.

Claims

1. A shower drain system for recovering thermal energy from a flow of shower greywater comprising: a drain cup for receiving shower greywater, a heat exchanger arranged downstream of the drain cup, the heat exchanger being configured to heat a flow of incoming cold water with the shower greywater, the drain cup comprising a drain cup inlet for receiving the shower greywater, and a drain cup outlet for discharging shower greywater to the heat exchanger, wherein the drain cup comprises a nozzle arranged and configured to supply hot water into the drain cup, the nozzle being arranged downstream of the drain cup inlet and upstream of the drain cup outlet, and being arranged and configured to face the drain cup outlet.

2. The system according to claim 1, wherein the drain cup is arranged and configured to, when hot water is supplied to the drain cup via the nozzle, act as an ejector by that the hot water acts as a motive fluid, forming a pumping effect within the shower drain system.

3. The system according to claim 1, wherein the drain cup comprises an ejector diffusion portion arranged between the nozzle and the drain cup outlet, the ejector diffusion portion having at least a converging section and/or a diverging section.

4. The system according to claim 3, wherein the diverging section is an asymmetrical diverging section.

5. The system according to claim 1, comprising a connecting conduit arranged between the drain cup and the heat exchanger, the connecting conduit having a diameter at least twice the diameter of an orifice of the nozzle.

6. The system according to claim 1, wherein the drain cup is arranged and configured to at least temporarily hold a detergent.

7. The system according to claim 6, wherein the drain cup comprises a measuring arrangement arranged and configure to measure the amount of detergent added to the system.

8. The system according to claim 1, wherein the drain cup is arranged and configured to hold a filtering unit T such as a strainer.

9. The system according to claim 1, comprising a nozzle connecting conduit arranged to fluidly couple the nozzle to tap water.

10. A shower or shower cabin comprising: a shower arrangement having a shower mixer configured to mix hot water from a hot water supply and pre-heated cold water from a cold water supply, and a shower head fluidly connected to the shower mixer for supplying shower water; a shower drain system according to claim 1.

11. The shower or shower cabin according to claim 10, wherein the nozzle of the shower drain system is arranged and configured to supply hot water from the same hot water supply as the shower mixer.

12. The system according to claim 9, wherein the filtering unit comprises a strainer.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) These and other aspects of the present inventive concept will now be described in more detail, with reference to the appended drawings showing an example embodiment of the inventive concept, wherein:

(2) FIG. 1 schematically illustrates a shower or shower cabin comprising a shower drain system for recovering thermal energy from a flow of shower greywater, in accordance with at least some example embodiments of the inventive concept;

(3) FIG. 2 illustrates a cross-sectional detail of the shower drain system of FIG. 1 according to at least one example embodiment of the inventive concept, and

(4) FIG. 3 illustrates a cross-sectional detail of a shower drain system according to at least yet another example embodiment of the inventive concept.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

(5) In the present detailed description, various embodiments of the inventive concept are described mainly with reference to a shower (or shower cabin) comprising a shower drain system for recovering thermal energy from a flow of shower greywater

(6) FIG. 1 is a schematic view illustrating a shower or shower cabin 100. The shower or shower cabin 100 comprises a shower tray or floor 22, and shower walls 22. The shower walls 22 are either attached to the building in which the shower 100 is installed, or are separated from the building and thus forming part of a shower cabin 100. Correspondingly, the shower tray or floor 22 is either attached to the building (i.e. constituting a shower floor of a shower), or is separated from the building (i.e. constituting a shower tray of a shower cabin) For simplicity, the shower or shower cabin 100 will in the following be described simply as a shower 100, and the shower tray or floor 22, as a shower floor 22.

(7) The shower 100 further comprises a shower mixer 17 and a shower head 18, the shower head 18 being fluidly connected to the shower mixer 17 by a shower conduit 19, being for example a shower hose or shower pipe. The shower mixer 17 is configured to mix hot water from a hot water supply 15, e.g. a hot tap water supply, and pre-heated cold water from a cold water supply, the latter being pre-heated cold water from a heat exchanger 1 as will be described in the following. During use, the shower mixer 17 mixes the desired amount of pre-heated cold water and hot water, supplies the mixed water to the shower head 18 via the shower conduit 19, whereby shower water for showering is provided. The shower water subsequently encounters the shower floor 22, and enters a shower drain system 200 as shower greywater. The shower greywater typically comprises debris, such as textile fibers and hair, as well as grease and shower products, as a result of the showering.

(8) In the following, the shower drain system 200 will be described in further detail. The shower drain system 200 comprises a drain cup 10 for receiving the shower greywater (the drain cup 10 is shown in greater detail in FIG. 2) and a heat exchanger 1 arranged downstream of the drain cup 10. A connecting conduit 6 is fluidly connecting the drain cup 10 and the heat exchanger 1.

(9) The drain cup 10 comprising a first filtering unit 9 for filtering debris from the shower greywater, and a second filtering unit 24 arranged downstream of the drain cup 9 for filtering debris from the shower greywater. Thus, the shower drain system 200 of FIG. 1 comprises two filtering units 9, 24 arranged and configured to filter debris from the shower greywater at different locations in the system 200. In FIG. 1, the first filtering unit 9 is embodied as a first strainer 9, and the second filtering unit 24 is embodied as a second strainer 24.

(10) The heat exchanger 1 of FIG. 1 will now be described in further detail. The heat exchanger 1 comprises a heat exchanger inlet 8 for receiving shower greywater from the drain cup 10 and connecting conduit 6, and a heat exchanger outlet 3 for discharging shower greywater out from the heat exchanger 1 to a sewer or residential drainage 21. The heat exchanger 1 further comprises a cold water inlet 4 for receiving cold water from a cold water supply 23 and a cold water outlet 5 for discharging the pre-heated cold water to the shower mixer 17. Thus, the heat exchanger 1 is configured to heat a flow of incoming cold water from the cold water supply 23 with the shower greywater. In FIG. 1, the heat exchanger 1 is a plate heat exchanger comprising heat transfer surfaces 1 arranged and configured to transfer heat from the shower greywater to the incoming cold water. Note that the heat exchanger 1 of FIG. 1 is schematically illustrated, and that e.g. the heat exchanger 1 may be vertically arranged instead of horizontally arranged, as shown in FIG. 1.

(11) The second strainer 24 is in FIG. 1 arranged to cover the heat exchanger inlet 8 and may be covered by a lid 25. Preferably, the second strainer 24 is removably attached to the heat exchanger 1, and may thus be removed by first removing the lid 25, or be attached to the lid 25, so that the lid 25 and strainer 24 is removed together. The second strainer 24 comprises a second mesh 24A with a second mesh size. In more detail, and as shown in the enlarged view of FIG. 1, the second mesh 24A form slits 24B (only one of the slits 24B is indicated in the enlarged view of FIG. 1) through which the shower greywater is enabled to flow. The slits 24B has a main extension in a direction perpendicular to the intended flow of shower greywater. As noted in FIG. 1, the direction of the flow of shower greywater is forced to rapidly change as it enters the heat exchanger 1 from the connecting conduit 6. Such rapid change in direction of the flow, e.g. a change of flow direction of between 60? and 90?, together with the second strainer 24 and the slits 24B, cause e.g. hair to stuck in the second strainer 24 even though the diameter of the hairs is significantly smaller than the second mesh size.

(12) FIG. 2 is a schematic cross-sectional view of the drain cup 10 of FIG. 1. As shown in FIG. 2, the drain cup 10 comprises the first filtering unit 9, or first strainer 9, being shaped as a bowl-, cone- or pocket shaped strainer extending from a top portion of the drain cup 10A and into the drain cup 10. The first strainer 9 comprises a first mesh 9A with a first mesh size. Briefly turning back to FIG. 1 and comparing with FIG. 2, it is evident that the second strainer 24 and the second mesh size of the second mesh 24A is coarser than the first mesh size of the first mesh 9A of the first strainer 9. Hereby, an efficient removal of debris (such as textile fibers and hair) from the shower greywater can be achieved with no, or at least a relatively low, reduction in fluid flow.

(13) In FIG. 2, the drain cup 10 comprises bottom wall 10B with a bottom surface 10C facing into the drain cup 10, and an enveloping side wall 10D extending perpendicular from the bottom wall 10B to an oppositely arranged opening 10E of the drain cup 10. The enveloping side wall 10D preferable comprises an at least partly cylindrically shaped portion. In FIG. 2, the opening of the drain cup 10 forms a drain cup inlet 10E for receiving the shower greywater. Moreover, the drain cup 10 comprises a drain cup outlet 7 for discharging shower greywater downstream to the heat exchanger 1 via the connecting conduit 6.

(14) The drain cup 10 further comprises a nozzle 11 arranged downstream the drain cup inlet 10E and upstream the drain cup outlet 7. In FIG. 2, the nozzle 11 is arranged in the enveloping side wall 10D, facing the drain cup outlet 7. Between the nozzle 11 and the drain cup outlet 7, the drain cup 10 comprises an ejector diffusor portion 30 having a converging section 12, a diverging section 14 arranged downstream of the converging section 12 and a constant area or throat section 13 arranged between the converging section 12 and the diverging section 14. Preferably, the diverging section 14 is asymmetrical to enable gas bubbles to escape back through the drain cup 10 and out via the first strainer 9. That is, the diverging section 14 does not form any compartment in which air or gas can be trapped, as a top portion of the diverging section 14 is in-line with a top portion of the connecting conduit 6, as well as in-line with a top portion of the constant area section 13.

(15) The nozzle 11 is arranged and configured to supply hot water into the drain cup 10, and more specifically into the ejector diffusor portion 30. When hot water is supplied to the drain cup 10 via the nozzle 11, the nozzle 11 and ejector diffusor portion 30 acts as an ejector. In more detail, as a stream, or jet, of hot water is injected by the nozzle 11 towards, and possibly into, the ejector diffusor portion 30, an ejector function is achieved (i.e. a fluid transporting and pumping effect). That is, as shown in FIG. 2, the nozzle 11 and the ejector diffusor portion 30 are axially aligned. Thus, by arranging the nozzle 11 to face the ejector diffusor portion 30, the ejector function is enabled as the fluid in the drain cup 10, and the ejector diffusor portion 30, may be transported and subject to an increased pressure by the supplied hot water from the nozzle 11. A centre axis C of the nozzle 11, indicated by the dashed line C in FIG. 2, thus extends through the orifice of the nozzle 11 and further into the ejector diffusor portion 30. The ejector diffusor portion 30 typically comprises a tubular pipe section 31 having a main extension in the direction of the centre axis C of the nozzle 11. Such tubular pipe section 31 may comprise the converging section 12, the diverging section 14 and the constant area or throat section 13. However, according to at least one example embodiment, the tubular pipe section 31 only comprises one of, or two of, the converging section 12, the diverging section 14 and the constant area or throat section 13. That is, the tubular pipe section 31 may simply be a diverging, converging, or a constant area tubular pipe section, arranged in the drain cup 10 to face the nozzle 11 (e.g. being axially aligned with the nozzle 11 such that the centre axis C at least extends into the tubular pipe section 31).

(16) Briefly turning back to FIG. 1 and comparing with FIG. 2, it is evident that the diameter d of the nozzle 11, or of an orifice of the nozzle 11, is smaller than the diameter D of the connecting conduit 6 at least by a factor 2. Such difference in the diameters d, D is advantageous and provides an improved ejector function when hot water is supplied to the drain cup 10 via the nozzle 11.

(17) As seen in FIG. 1 and FIG. 2, the drain cup 10 is arranged vertically with the bottom surface 10C being planar and extending perpendicular to the vertical axis V. The bottom surface 10C may alternatively be arranged with an angle of 60?-120? relative the vertical axis V. Thus, the height of the drain cup 10 extends along the vertical axis V, and the bottom surface 10C extends perpendicular to the height. Hereby, the drain cup 10 may at least temporarily hold a detergent, such as e.g. a solid detergent, e.g. a detergent in the form of a powder or granulates, as the detergent may be kept in the drain cup 10 at the bottom surface 10C. Moreover, the amount of detergent in the drain cup may be measured or estimated by a measuring arrangement 27, in FIG. 2 embodied as a level marker 27.

(18) Moreover, the drain cup 10 in FIG. 1 and FIG. 2 is arranged and configured to, during use, at least temporarily hold the shower greywater. That is, the drain cup 10 is arranged such that the drain cup 10 may be temporarily filled with the shower greywater during use (i.e. when the drain cup 10 is receiving shower greywater from the shower 100), enabling the drain cup 10 to be filled to a certain amount before a steady state is reached in which an equal amount of shower greywater is discharged through the drain cup outlet 7, as is entered via the drain cup inlet 10E. Hereby, a hydraulic pillar may be formed in the drain cup, the hydraulic pillar extending above at least a portion of the first strainer 9. Such hydraulic pillar forces the flow of shower greywater through the first strainer 9, avoiding easy blockage of the first strainer 9, and avoiding the shower greywater level to rise on the shower floor.

(19) Moreover, various valves 16, 20, 26 may be comprised in the shower 100 and/or shower drain system 200, such as e.g. a first control valve 16 for regulating the flow of hot water to the nozzle 11 via a nozzle connecting conduit 15, a second control valve 20 for regulating the flow of discharged shower greywater from the heat exchanger 1 (and for enabling closing of the system 200 as described below), and a check valve 26 arranged upstream of the first control valve 16 in the hot water supply to the nozzle 11. Such valves are known to the skilled person and is not further elucidated. The control valve 16 may instead of being arranged on the supply line to the nozzle 11, be arranged as a three-way valve between the hot water supply 15, the supply line of hot water to the shower mixer 17 and the supply line of hot water to the nozzle 11. Such three-way valve would prevent simultaneously addition of hot water via the nozzle 11 and the shower mixer 17 and shower head 18. The nozzle connecting conduit 15 typically has a downstream end portion ending in the nozzle 11, and an upstream end portion ending in a coupling to the hot water supply, e.g. tap water, or hot tap water. Thus, the nozzle 11 is typically fluidly coupled to the hot water supply via the nozzle connecting conduit 15.

(20) As seen in FIG. 1, the shower 100 utilizes the same hot water supply 15 for the hot water input to the shower mixer 17, as for the nozzle 11 (via the nozzle connecting conduit 15). Hereby, hot water, such as hot tap water, directly from the hot water supply 15, which have not been subject to a temperature reduction in the shower mixer 17 (e.g. by shunting pre-heated cold water into the hot water), can be used. Moreover, by providing hot water directly from the hot water supply 15 (e.g. a tap water supply) to the nozzle 11, a reliable pressure and temperature of the hot water can be assured.

(21) FIG. 3 is a schematic cross-sectional view of a drain cup 110 similar to the drain cup 10 of FIG. 1 and FIG. 2, why only the differences are highlighted below, mainly concerning the ejector diffusor portion 130. Thus, other structures and features not described for the embodiment of FIG. 3 is typically the same, or corresponding to the corresponding structures and features described for the embodiment of FIG. 2, why the same reference numerals are used in FIG. 3 without undue repetition. As shown in FIG. 3, the nozzle 11 and the ejector diffusor portion 130 are at least partly axially aligned, as the centre axis C enters into the ejector diffusor portion 130 but is not parallel to a centre axis of the ejector diffusor portion 130 itself. However, the nozzle 11 is still arranged to face the ejector diffusor portion 130, and the ejector function is thus enabled as the fluid in the drain cup 110, and the ejector diffusor portion 130, may be transported and subject to an increased pressure by the supplied hot water from the nozzle 11. As in FIG. 2, the ejector diffusor portion 130 comprises a tubular pipe section 131 having a main extension slightly inclined relative the centre axis C of the nozzle 11. In FIG. 3 the tubular pipe section 131 only comprises a converging section 112, and a constant area section 113 (thus, no diverging section is present in the tubular pipe section 131 of FIG. 3).

(22) The nozzle 11 is arranged and configured to supply hot water into the drain cup 110, and more specifically into the ejector diffusor portion 130. When hot water is supplied to the drain cup 110 via the nozzle 11, the nozzle 11 and ejector diffusor portion 130 acts as an ejector. In more detail, as a stream, or jet, of hot water is injected by the nozzle 11 towards, and possibly into, the ejector diffusor portion 130, an ejector function is achieved (i.e. a fluid transporting and pumping effect).

(23) The drain cup 110 of FIG. 3 may be used in the shower or shower cabin 100 of FIG. 1 instead of the drain cup 10 of FIG. 2.

(24) The function, and cleaning, of the shower drain system 200 will now be described in further detail.

(25) Rapid fouling and blocking of the shower drain system 200 are prevented via the arrangement and configuration of the shower drain system 200 as shower greywater enters the drain cup inlet 10E, by the first strainer 9 and the second strainer 24 as previously described. For example, by the rapid change in direction of the flow as the shower greywater enters the heat exchanger 1 from the connecting conduit 6, together with the second strainer 24 and the slits 24B, causing e.g. hair to stuck in the second strainer 24 even though the diameter of the hairs is far smaller than the second mesh size.

(26) Cleaning of the shower drain system 200 is performed subsequently to a shower, i.e. when no shower greywater is entering the drain cup inlet 10E (i.e. when the shower or shower cabin is not used for showering). For example, thermal cleaning may be performed by simply opening control valve 16 and supplying hot water into the drain cup 10 by the nozzle 11. The temperature of the hot water is preferably between 50? C. and 55? C. and the pressure is preferably between 1 and 7 barg, causing waxes and grease to melt and be removed together with the supplied hot water eventually to the sewer or residential drainage 21. The hot water supplied by the nozzle 11 furthermore achieves the previously described ejector function improving the cleaning and detains greywater deposits of hair, fibers and grease to backflow onto the shower floor. Moreover, air may be drawn into the system during use of the nozzle 11 to supply hot water into the drain cup 10. Drawn air may form a pulsating effect of the injected hot water by the nozzle 11, further improving the cleaning effect. Such air is not trapped in the system and will be automatically removed during a subsequent flow of shower greywater of an upcoming shower.

(27) Chemical cleaning may additionally, or alternatively, be performed by adding a detergent as previously described. Chemical cleaning is typically preformed subsequently to a shower, i.e. when no shower greywater is entering the drain cup inlet 10E, and typically subsequently to thermal cleaning. During chemical cleaning, the control valve 20 is typically closed, detergent, e.g. in form of a powder or granulates, are added to the drain cup subsequent to a removal of the first strainer 9 (and the amount measured using the measuring arrangement 27) where after the control valve 16 is opened and hot water is supplied into the drain cup 10 via the nozzle 11, distributing the detergent into the system. Subsequent to such chemical cleaning, a thermal cleaning as described above may be performed in order to remove any detergent and dissolved grease and fibrous material from the system. For such thermal cleaning/rinsing, the control valve 20 is typically opened.

(28) Even though the inventive concept has been described with reference to specific exemplifying embodiments thereof, many different alterations, modifications and the like will become apparent for those skilled in the art. For example, the drain cup 10 and its specific configuration with the nozzle 11 and the ejector section 30 may be used without e.g. the second strainer 24. Correspondingly, the configuration with the first strainer 9 having a first mesh 9A with a first mesh size, and second strainer 24 having a second mesh 24A with a second mesh size being coarser than the first mesh size, may be used without the specific configuration of the drain cup 10 (e.g. the nozzle 11 and the ejector diffusor section 30). Also, it should be noted that the heat exchanger 1 may be arranged differently to that of FIG. 1, and e.g. be a tube heat exchanger. Moreover, the shower drain system described herein is applicable for a shower tray (i.e. a shower cabin without the walls).

(29) Additionally, variations to the disclosed embodiments can be understood and effected by the skilled person in practicing the claimed inventive concept, from a study of the drawings, the disclosure, and the appended claims. In the claims, the word comprising does not exclude other elements or steps, and the indefinite article a or an does not exclude a plurality. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.