Flushing Bypass System

Abstract

A flushing bypass system, particularly for use in a district or communal heating system, has a primary circuit 2 capable of supplying heat to a secondary circuit 10, the secondary circuit normally supplying heating through radiators 11 and/or hot water from tank 14 for occupants. The primary circuit has a furcated strainer 3 upstream from at least one heat exchanger and a limb of the furcated strainer is connected to a heat exchanger bypass assembly. The bypass assembly comprises a valve 21, which may be a timer valve, a manual valve or a smart valve, having an input 20 connected to the furcated strainer and an output 24 connected back into the primary circuit downstream of the heat exchanger. When the valve 21 is closed fluid passes through the furcated strainer to the heat exchanger and when the valve is open, fluid bypasses the heat exchanger and flushes contaminants from the furcated strainer back to the primary circuit downstream of the heat exchanger.

Claims

1: A flushing bypass system for a fluid system including equipment (11, 14) that needs protecting from debris and contaminants in the fluid, said fluid system including a furcated strainer (3), characterized in that said bifurcated strainer (3) is located in a flow path upstream to said equipment, said furcated strainer being connected to a bypass assembly comprising valve means (21) having input (20) and output (22, 24) connector means, said input connector means being arranged to be connected to said furcated strainer and said output connector means (22, 24) being arranged to be connected downstream of the said equipment (11, 14), whereby when the valve means (21) is closed fluid passes through the furcated strainer (3) to the equipment (11, 14), and when the valve means (21) is open, fluid bypasses said equipment (11, 14) and flushes contaminants from the furcated strainer (3) downstream of said equipment (11, 14).

2: A flushing bypass system for use in a district or communal heating system including a primary circuit (2) and a secondary circuit (10), said secondary circuit (10) including at least one heat exchanger (8, 11, 14) supplying heating and/or hot water for occupants, said primary circuit having a furcated strainer (3) in a flow path upstream to said secondary circuit (10), characterized by said furcated strainer (3) being connected to a bypass assembly comprising valve means (21) having input (20) and output (22, 24) connector means, said input connector means being arranged to be connected to said furcated strainer and said output connector means being arranged to be connected downstream of the said at least one heat exchanger (8, 11, 14), whereby when the valve means is closed fluid passes through the furcated strainer to the at least one heat exchanger, and when the valve means is open, fluid bypasses the at least one heat exchanger and flushes contaminants from the furcated strainer to the primary circuit downstream of the at least one heat exchanger.

3: A system as claimed in claim 2, wherein the furcated strainer (3) is one of a strainer newly installed in the primary circuit of said system, a strainer pre-existing in the primary circuit of said system, and an additional furcated strainer provided in the primary circuit either upstream or downstream of a pre-existing furcated strainer in the primary circuit.

4: A system as claimed in claim 1, wherein the input connector means (20) of said valve means (21) is a flushing nipple connected to the furcated strainer (3).

5: A system as claimed in claim 2, wherein the output connector means is a pipe (23) and a T-piece (24) connecting the pipe from the downstream side of the valve means to the T-piece in the primary circuit (2).

6: A system as claimed in claim 1, wherein the valve means (21) is arranged to be opened at periods of low occupant heat requirement, for example at night.

7: A system as claimed in claim 2, wherein the valve means (21) is arranged to be opened at periods of low occupant heat requirement, for example at night.

8: A system as claimed in claim 1, wherein the valve means (21) is one of a timer valve, a manually operable valve, and a smart valve operable from a remote source such as a telephone.

9: A system as claimed in claim 8, wherein where the valve means (21) is a smart valve, said smart valve includes a receiver for receiving signals from the remote source and in dependence thereon is arranged to open or close a fluidic valve.

10: A system as claimed in claim 2, wherein the heating system is one of an indirect and a direct heating system.

11: A system as claimed in claim 1, wherein the furcated strainer (3) is one of a strainer newly installed upstream of said equipment, a strainer pre-existing upstream of said equipment, and an additional furcated strainer provided either upstream or downstream of a pre-existing furcated strainer upstream of said equipment.

12: A system as claimed in claim 2, wherein the input connector means (20) of said valve means (21) is a flushing nipple connected to the furcated strainer (3).

13: A system as claimed in claim 3, wherein the input connector means (20) of said valve means (21) is a flushing nipple connected to the furcated strainer (3).

14: A system as claimed in claim 3, wherein the valve means (21) is arranged to be opened at periods of low occupant heat requirement, for example at night.

15: A system as claimed in claim 4, wherein the valve means (21) is arranged to be opened at periods of low occupant heat requirement, for example at night.

16: A system as claimed in claim 5, wherein the valve means (21) is arranged to be opened at periods of low occupant heat requirement, for example at night.

17: A system as claimed in claim 12, wherein the valve means (21) is arranged to be opened at periods of low occupant heat requirement, for example at night.

18: A system as claimed in claim 13, wherein the valve means (21) is arranged to be opened at periods of low occupant heat requirement, for example at night.

19: A system as claimed in claim 2, wherein the valve means (21) is one of a timer valve, a manually operable valve, and a smart valve operable from a remote source such as a telephone.

20: A system as claimed in claim 19, wherein where the valve means (21) is a smart valve, said smart valve includes a receiver for receiving signals from the remote source and in dependence thereon is arranged to open or close a fluidic valve.

Description

[0031] The invention will now be described, by way of example, with reference to the accompanying drawings in which:

[0032] FIG. 1 shows, in schematic form, a heating system of an indirect type in accordance with this invention, and

[0033] FIG. 2 shows in schematic form, a heating system of a direct type in accordance with this invention.

[0034] In the Figures like reference numerals denote like parts.

[0035] Referring to FIG. 1, a district or communal heating system of the indirect type is shown in the drawing in which a heat interface unit (HIU) has a water flow input 1 to a primary circuit 2. Fluid, normally water, in the primary circuit flows into a furcated strainer 3, which may be, for example, a strainer made by Tacotherm Limited, in which there is a strainer filter 4 in a limb of the strainer which abuts a constricting portion 5. In a known, currently used system, the strainer 3 has an external portion 6 which is closed by a blanking plug. Water flowing past the constricting portion 5 through the filter of the strainer 4 passes through a pipe 7 via a valve 9 operable by a timer/programmer (not shown) to a heat exchanger 8 of the HIU, for example made by Alfa Laval, where heat within the primary water system is exchanged to a secondary circuit 10 that feeds customer radiators 11, only three being shown by way of example, and a hot water tank (cylinder) 14. The valve 9 is normally controlled by an occupant via a programmer. The programmer may be set to provide heat and/or hot water by setting on/off times using a timer facility on the programmer, or switching on and off manually.

[0036] In the exemplary embodiment, a valve 15 is provided between the heat exchanger 8 and the radiators. The valve 15 is a three-port valve used to divert water in the secondary system to the radiators 11 or to the hot water tank 14. The valve 15 is, preferably, controlled by a timer/programmer (not shown) to supply water from the secondary circuit, in one position thereof, to a heating coil within a hot water tank (cylinder) 14, and in another position thereof to the radiators 11. Output from the radiators and the heating coil is fed back into the heat exchanger 8. Water in the primary system flows through the heat exchanger 8 and back into a primary system pipe 12 where it exits at outlet 13. Heat flow through the primary and secondary circuits is indicated by arrow headed lines.

[0037] The present invention provides the additional serial components of a flushing nipple 20 that is connected into the strainer 3 in place of the blanking plug, the flushing nipple 20 being connected to, in one preferred embodiment, a timer valve 21, which, for example may be Tofine Group Company Limited model TCM30P, a fluid connector 22, and a pipe 23 to a T-piece 24 interconnecting with the primary circuit in pipe 12. Where it is not practical to connect to an already existing furcated strainer an additional furcated strainer may be added in place of, or in addition to, the existing furcated strainer and the additional furcated strainer may be located either upstream or downstream of the pre-existing furcated strainer.

[0038] The timer valve 21 acts as a plug when the valve 21 is closed enabling the mesh to catch any debris in the primary water circuit so that it may fulfil its primary function of protecting the heat exchanger 8. The timer valve 21 preferably, has an electronic timer that may be set to open a number of times a day for a period determined by a user. Tests have shown that the best cleaning results are achieved by setting the timer valve 21 to open a minimum of two to three times a day for a period of five to ten minutes each to maximise the opportunity for removing debris from the mesh. Such action also prevents debris from consolidating on the inside of the mesh which may reduce the effectiveness of the automatic flushing process. The operation of the timer valve 21 may be set to occur at times of low or no heat demand to avoid occupants being affected by the periods when flushing is taking place, since during that period there will be no heat provided to the radiators 11 or hot water tank 14.

[0039] When the flushing timer valve 21 opens it allows primary water to flush through the strainer filter 4 at system pressure which is normally between two and ten bar, thereby removing any debris from the mesh of the filter and allows the water to pass back into the primary circuit downstream of the flushing timer valve 21 and heat exchanger 8.

[0040] When the timer valve 21 closes, the system returns to its normal function and the flow of heat is restored because the mesh of the filter 4 has been cleaned. In a badly affected system where the filter mesh becomes blocked every day, the fact that it is cleaned every day will enable occupants to have continual heat, except during the flushing process. The pipe 23 and T-piece 24 downstream of the flushing timer valve 21 act to bypass and protect the heat exchanger, and return any contaminated water back to the primary circuit 2 downstream of the heat exchanger 8. It will be understood that debris bypasses the heat exchanger 8 and flows freely back to a plant room (not shown) receiving water from outlet 13 where the debris may be collected in a master strainer or, in some circumstances, returned to the primary circuit 2. However, this latter operation is not recommended, since it is inadvisable to allow debris to enter the primary circuit.

[0041] The heating system shown in FIG. 2 is a direct system in which the heat exchanger 8 is omitted with fluid flow from the primary circuit 2 passing via the strainer 3 and valve 9 to the secondary circuit 10.

[0042] Thus, when timer valve 21 is closed and valve 9 is open, fluid passes into the secondary circuit 10 and, in dependence upon the position of valve 15, as determined by the programmer/timer (not shown), fluid passes into the radiators 11 and/or the heating coil of tank 14, thence back into the primary circuit. When timer valve 21 is open fluid flushes through the strainer filter 4 to clean the filter and the fluid bypasses the secondary circuit 10.

[0043] A major benefit of the present invention is that it provides a landlord with the ability to automatically flush debris back to the plant room where it can be caught by a master strainer. Thus, over time, an already contaminated system will clean itself and so the present invention has great advantage as a retro-fit kit.

[0044] From the foregoing it will be understood that the present invention is an automatic bypass assembly which automatically flushes debris from a furcated strainer, bypassing and protecting heat exchangers 8, 11 and 14 and restoring a heat supply to an occupant via radiators 11 and hot water via tank 14. The present invention does not require manual intervention and operates by connecting the furcated strainer to a flushing nipple which, in turn, is connected to a flushing timer valve 21 that is set to clean the strainer for a pre-set period, or a number of pre-set periods, each day at a time which will not cause disruption to occupants. Debris that is flushed from the strainer bypasses the heat exchanger and is returned to the primary circuit downstream of the heat exchanger from whence it may be returned to a plant room.

[0045] It will be understood that the flushing bypass assembly of the present invention automatically removes debris from the primary circuit and restores heat supply to an occupant by maximising the flow rate through the heat exchangers. In a blocked strainer the flow rate may be reduced to zero as the strainer becomes increasingly blocked. The flow rate in a domestic system normally needs to be above five hundred litres/hour in order to allow heat to be transferred to the secondary circuit at a rate that is fast enough to enable the occupants to obtain hot water and space heating. Thus, flow rate is critical. By restoring the flow rate using this invention, occupants are able to enjoy heating and hot water. By providing an automatic flushing system, occupants and landlords are saved the cost of calling out an engineer. Further, a clean strainer reduces the amount of time that occupants have to wait for hot water and heating by maximising the flow rate through the heat exchanger, thereby improving the efficiency of the heat supply and providing improved functionality of the heating system. The improved efficiency results in reduced heat costs because occupants do not need to run their system for longer than necessary to obtain the heat required.

[0046] The cost of manually flushing an entire primary circuit is generally between 10,000-85,000 depending on the size of scheme and number of blocks/rises that need flushing and this cost is substantially avoided by the present invention.

[0047] It is anticipated that the present invention will be used in newly installed systems and will have great benefit as a retro-fit kit in existing heating systems.

[0048] In an alternative embodiment, instead of using timer valve 21, a manually operable valve may be utilised which may be operated on a regular basis or when a problem is found by a user.

[0049] In yet another embodiment, a smart valve having a receiver for receiving signals over the ether may be utilised, the receiver operating the valve when signalled to do so. The signals may be transmitted from a remote source, such as a telephone that may be connected to a landline, or a cellular phone. Again, in such an embodiment the smart valve would be a fluidic valve operable at times determined by a user.

[0050] It will be understood that the present invention is not limited to use in a heating system and may be employed where equipment needs to be protected from debris and contaminants by a strainer located upstream of the equipment, such as cooling pipes where it is desired to protect coils and heat exchangers, or on fuel lines, or milk processing plant, or any fluid process where fluid passes through pipes and equipment that needs protecting from debris and contaminants in the fluid by a strainer located upstream of the equipment. In this respect, the invention provides a flushing bypass assembly whereby the strainer is cleansed by flushing the contaminants to a point downstream of the equipment.