SLEEVE BREAK DETECTOR FOR UV DISINFECTION SYSTEM LAMP ASSEMBLY

Abstract

A UV disinfection system including at least one UV lamp assembly with a sleeve surrounding a UV lamp and defining an inner volume. The UV disinfection system further includes at least one pressure sensor. At least one non-return valve connects the inner volume of the at least one sleeve to the pressure sensor. The UV disinfection system is configured to detect a sleeve breakage by the resulting change in pressure at the at least one pressure sensor. A break detection device for a UV disinfection system with a pressure detector includes at least one tubing which communicates directly or indirectly with an inner volume of a sleeve surrounding at least one of a UV lamp unit.

Claims

1-14. (canceled)

15. A UV disinfection system, comprising: at least one UV lamp assembly, each UV lamp assembly comprising a sleeve surrounding a UV lamp and defining an inner volume, at least one pressure sensing means, and at least one non-return valve connecting the inner volume of the sleeve to the pressure sensing means; wherein the UV disinfection system is configured to detect breakage of the sleeve by detecting a change in pressure at the at least one pressure sensing means.

16. The UV disinfection system of claim 15, wherein the pressure sensing means comprises a pressure switch, a pressure transducer, or a combination thereof.

17. The UV disinfection system of claim 15, further comprising an interface configured to directly or indirectly connect a sleeve breakage alarm to the UV disinfection system.

18. The UV disinfection system of claim 17, wherein the sleeve breakage alarm comprises a passive controller having an open or closed contact to a subsequent user operated controller.

19. The UV disinfection system of claim 15, further comprising a fluid inlet valve for controlling fluid entering the UV disinfection system, a fluid outlet valve for controlling fluid leaving the UV disinfection system, or a combination thereof.

20. The UV disinfection system of claim 19, wherein: i) the pressure sensing means is configured to directly control at least one of the fluid inlet valve and the fluid outlet valve, wherein the pressure sensing means comprises a pressure switch, a pressure transducer, or a combination thereof; ii) the UV disinfection system further comprises a controller configured to directly or indirectly control the at least one of the fluid inlet valve, the fluid outlet valve, or combination thereof, or iii) a combination of (i) and (ii).

21. The UV disinfection system of claim 15, wherein the pressure sensing means is connected directly or indirectly to the inner volume of the sleeve by a passage.

22. The UV disinfection system of claim 21, wherein the passage comprises tubing.

23. The UV disinfection system of claim 22, wherein the tubing comprises pneumatic tubing.

24. A break detection device for a UV disinfection system having at least one UV lamp unit with a sleeve defining an inner volume surrounding the at least one UV lamp, the break detection device comprising: a pressure detection means; at least one tubing providing direct or indirect communication between the pressure detection means and the inner volume of the sleeve.

25. The break detection device of claim 24, further comprising a non-return valve disposed between the inner volume of the sleeve and the pressure detection means.

26. The break detection device of claim 24, wherein the UV disinfection system comprises at least two UV lamp units, each UV lamp unit having a corresponding sleeve and a corresponding inner volume, and the at least one tubing comprises at least two tubings, each tubing pneumatically connected between the corresponding inner volume of one of the at least two UV lamp units and a manifold having two or more pneumatic ports.

27. The break detection device of claim 26, further comprising a non-return valve disposed between the inner volume of each corresponding sleeve and the pressure detection means, the non-return valve disposed so that a fluid can unidirectionally pass from each of the at least two tubings into the manifold.

28. The break detection device of claim 27, wherein the manifold comprises a pressure release valve adapted to de-pressurize the manifold.

29. The break detection device of claim 27, wherein the manifold comprises a pressure test port adapted to pressurize the manifold.

30. An end piece of a UV lamp assembly of a UV water disinfection system, the UV lamp assembly comprising a UV lamp and a sleeve defining an inner volume surrounding the UV lamp; the end piece comprising: a fluid connection port in communication with the inner volume of the sleeve.

31. A UV water treatment plant comprising the UV disinfection system of claim 15.

32. A UV water treatment plan comprising the break detection device of claim 24.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In the following, embodiments are described referring to the drawing, which show:

[0030] FIG. 1: a single lamp assembly with a port to be connected to an associated glass break detection device;

[0031] FIG. 2: a schematic layout of a UV disinfection system with multiple UV lamp assemblies;

[0032] FIG. 3: a schematic layout of a plant with glass break detection and safety shutdown functionality; and

[0033] FIG. 4: a schematic pressure vs. time diagram showing pressure inside the manifold in normal operation and in a sleeve break incident.

DETAILED DESCRIPTION OF THE DRAWINGS

[0034] FIG. 1 shows a single UV lamp assembly with a port to be connected to an associated glass break detection device. In greater detail, the lamp assembly 1 comprises an elongate ultraviolet lamp 2 which is housed in a sleeve tube 3, which is made of quartz glass. The details of the lamp 2, which may be a low-pressure mercury amalgam discharge lamp in this embodiment, are generally known. An end piece 4 of the assembly comprises a socket 5 for connecting the lamp 2 to an external power supply. The sleeve tube 3 has a closed end 6 and an open end 7, and the open end 7 is held inside the end piece 4 and hermetically sealed therein by, for examples, O-rings 8. The sleeve 3 and the end piece 4 define an inner volume of the lamp assembly 1. The end piece 4 is completely watertight and gas-tight, so that the lamp assembly 2 can be operated under water, as is usually the case.

[0035] However, the end piece 4 that is shown in FIG. 1 has a dedicated port 9 for attachment of a pneumatic hose (not shown here). The port 9 contains an open channel for the pneumatic connection between the volume inside the sleeve tube and a pneumatic tubing that may be connected to the port 9.

[0036] Thus, the port can be utilized to attach a device for monitoring the pressure inside the sleeve tube or, more precisely, register pressure changes and, if a threshold is reached, generate a signal accordingly. It should be understood that the end piece 4 having the port 9 can be retrofitted to all existing lamp assemblies with the same outer diameter of the sleeve tube. Since the sleeve tubes are in practice often of the same diameter, only very few types of end pieces may have to be provided to be able to retrofit a wide variety of UV water disinfection plants.

[0037] FIG. 2 shows a schematic layout of a UV disinfection system with multiple UV lamp assemblies 1. A number of lamp assemblies 1 (three in this case) are mounted in a common reactor chamber 10 for treating a flow of water that enters the reactor chamber 10 through an inlet port 11 and which is discharged through an outlet port 12. The inlet port 11 and the outlet port 12 are connected to valves (not shown) which are adapted to shut off or open the respective ports under the control of a control unit 13. A number of UV disinfection systems may be combined to form a UV disinfection plant. This may be necessary if the capacity of one system is not sufficient to handle the total demand. In this case, several systems may be implemented to work in parallel lines or channels.

[0038] Each lamp assembly 1 shows the port 9, which is connected to a pneumatic tubing 15. The pneumatic tubings 15 are individually attached to a common manifold 16 through individual non-return valves 17. Each non-return valve 17 allows overpressure to enter the manifold 16 from a pressurized tubing 15, and blocks pressurized fluid to proceed from the manifold 16 into other non-pressurized tubings. A pressure switch 18 is connected to the manifold 16. The switch 18 is shown in its normally closed state here. Other embodiments may utilize a normally open switch type instead. When the manifold 16 is pressurized, the switch 18 opens, which can be read-out by subsequent electronics. A manually operable pressure release valve 19 is also attached to the manifold 16. This valve 19 can be operated to release pressure from the manifold 16 in case it has been pressurized due to a glass break or due to a test condition.

[0039] In this embodiment, the control unit 13 is a low voltage control unit which operates e.g. at 24 Volts. With the normally closed pressure switch 18, the control unit 13 holds a relay 20, which will automatically switch to another state once the pressure switch opens. The relay 20 can freely be used to generate an alarm, trigger a message to operating personnel or any other desired action. A mains input isolator 21 and a 24 Volts ac/dc-converter 22 may be of any known type.

[0040] FIG. 3 shows a schematic layout of a plant with glass break detection and safety shutdown functionality. The basic layout is like already described with reference to FIG. 2, and like elements are marked with the same reference numerals.

[0041] The reactor chamber 10 is one of a number of essentially identical chambers which are mounted in parallel. The chamber 10 illustrated in FIG. 2 is an example that shows three lamp assemblies, hence the figure shows three pneumatic tubings 15 are connected to the manifold 16. The number of lamp assemblies can vary in number and configuration. The sleeve break detection system is scalable to cater for any number of lamps and chambers by either installing an additional system, expanding or “daisy-chained” together without non-return valves, so that their interior is at the same pressure anytime.

[0042] FIG. 3 shows a typical plant controller 23 configuration that detects the state of relay 20 and operates a fluid inlet valve 24 and/or a fluid outlet valve 25 via electric lines 26. The first plant controller 23 is thus enabled to close the fluid valves 24 and 25 depending on the switch state of relay 20, and consequently of pressure switch 18. A second plant controller 27 reads out another set of contacts of relay 20 and can perform other necessary actions upon a change of the switch state of relay 20 and pressure switch 18.

[0043] In operation, in a preferred embodiment, the reactor chamber 10 is filled with water at an elevated pressure, while the internal volume of the sleeve 3 is at atmospheric pressure. The same atmospheric pressure is found in the tubings 15 and inside the manifold 16. The pressure switch 18 is closed under these conditions. The UV lamps are operated to disinfect the water flow through the reactor chamber 10.

[0044] A glass break may occur due to foreign objects in the water flow and/or water hammer events. Such a sleeve break would give access of the pressurized water body to the inside volume of the (then cracked or broken) sleeve and, through the individual port 9 of the defunct lamp assembly, to the pneumatic tubing 15 which is attached to that port. The pressure rises in the manifold 16 and, above a pre-selected threshold, pressure switch 18 opens. The other tubings 15 are not pressurized because of the non-return valves 17 that are fitted to the manifold. This is especially important in case of water entering the manifold 16. Consequently, the relay 20 in the control unit 13 is switched and the plant controllers 23 and 27 take the intended action, for example the first plant controller 23 closes the valves 24 and 25 and shuts down the power supply to the lamp units 1 of the affected chamber 10, while the second plant controller 27 power up another set of UV lamp units in a parallel chamber (not shown here) and, after the set of lamp units has started, opens the inlet and outlet valves of the other chamber to continue the operation of the plant. An alarm will be generated, and service personnel can change the affected lamp unit. After the repair, pressure relief valve 19 is operated to release the pressure that is still present in the manifold 16 and operation can return to normal.

[0045] FIG. 4 shows the pressure p inside the manifold vs. time of operation in arbitrary units. The units could be hours t and bars p for example. Starting at t=0, the operation of the lamp begins at an internal pressure in the sleeves and inside the manifold of, e.g., 0.6 bars. During operation, the pressure in the sleeves rises to 1.0 bars due to the temperature increase caused by the heat that the lamps generate, or also maybe due to a rise in the water temperature over time. The pressure inside the manifold rises accordingly but cannot drop because of the non-return valves that prevent air flowing back into the sleeves when the temperature and the pressure in the sleeves drop. In this example, at 7 hours of operation, one sleeve breaks and causes an immediate rise in pressure to the water pressure in the reactor, which in this example is 6 bars. The alarm is produced, and personnel is replacing the lamp unit. During this time, the pressure in the manifold is constant at 6 bars. After the maintenance is completed after 8 hours of operation time, the service person operates the pressure release valve to reset the pressure in the manifold and consequently the alarm condition. Normal operation can commence. It is not only the high absolute pressure inside the manifold that indicates a sleeve break, but also the steep gradient of the rising pressure which occurs at 7 hours of operation in this example. Depending on the type of pressure sensing means, one or both conditions can be monitored and taken as an indication of a sleeve break, alone or in combination.

[0046] The use of pressure to detect a sleeve break eliminates the risk of not detecting an alarm due to water not coming into contact with electrical parts due to air locks and in the case where the lamps are not lit because the reactor is in standby, or the lamp is not operational so there is not electrical current to create a fault, the pressure change will still be detected and the alarm raised in the event of a sleeve break.

[0047] The use of pressure also helps with falsely reporting alarms, where if there is an electrical fault such as a faulty lamp, the system will be in the non-alarm state giving assurance that the sleeve is intact, and the lamp replacement can be scheduled saving downtime and emergency call outs.