MX2007000187A

MX2007000187A - Valve status monitoring.

Info

Publication number: MX2007000187A
Application number: MX2007000187A
Authority: MX
Inventors: Shane Michael Mason
Original assignee: Tyco Flow Control Pacific Pty
Priority date: 2004-07-05
Filing date: 2005-07-05
Publication date: 2007-04-17
Also published as: BRPI0513016A; ZA200700937B; RU2007104167A; BRPI0513016A8; RU2386069C2

Abstract

A valve apparatus has a valve (1), an actuator (2) and a leakage sensor (3). A body (4)of the valve has first and second valve chambers (6, 8) connected to respective valve ports (10 & 12, 14 & 16) and joined by an intermediate passage (18).The valve can be set by the actuator to any one of three valve configurations. In an 'open' configuration the intermediate passage is open to interconnect the first and second chambers. In a 'closed' configuration, the intermediate passage is closed by first and second seals (24, 26) seated at respective locations in the passage to seal respectively between the first and second chambers and a leakage chamber (28) at the portion of the intermediate passage between the two seals. In a 'cleaning' configuration one of the seals is unseated to connect a respective one of the first and second chambers to the leakage chamber, while the other seal remains seated. The leakage sensor is connected to the leakage chamber to provide a signal indicative of a lea kage flow from the leakage chamber.

Description

STATE MONITORING OF A VALVE FIELD OF THE INVENTION The present invention relates to an apparatus and method for monitoring the status of a fluid control valve, and in particular for monitoring an undesirable flow passage of the valve seal when the seal is established or for confirmation of a desirable flow of passage through the seal when the seal is not established BACKGROUND OF THE INVENTION Valves are generally used to control the flow of fluids in the production and processing of various products and materials Failure of valve seals can cause leakage or contamination of the flow of products controlled by the valves. It is therefore desirable to identify early seal failures before seal leaks reach levels of importance or contaminate the product. The prevention of contamination is particularly essential in the preparation of products such as food, beverages and medicines intended for animal or human consumption, for example, in addition, many products are manufactured or processed using pothole production methods and equipment cleaning such as containers and lines between potholes to prevent cross contamination between different products, or to avoid incrustation of molds, fungi, bacteria, and other pathogens being this at least desirable, but essential. In such situations it is desirable to be able to confirm the presence of correct cleaning or rinsing flows through the process plant U.S. Patent No. 4,655,253 discloses a shut-off valve comprising a valve housing with two chambers joined by an axial passage joined by the valve seat. A valve body has two axially-independent movable parts in the housing. Each part comprises a seal cooperating respectively with one of the seats to close between a chamber and an associated passage In an embodiment, a leak detection space is provided between the seats Fluid leaks through the seats within this space are discharged via a channel to provide a visible signal indicating the leak and avoid mixing the respective fluids in the two chambers US Pat. No. 5,361,802 discloses a valve block with metal electrodes. If the valve of the block fails to seal, the fluid leak closes a circuit between the electrodes to generate a signal that is processed by an analyzer to activate an alarm. which identifies the defective valve.

US Patent 5,594,162 discloses a gas leak detector that is adapted to fit around the steam control of a valve to monitor the leakage of a hydrocarbon gas from the valve.

U.S. Patent 5,616,829 discloses a valve with leak detector that monitors vibrations caused by leakage through the seats or a ganglion packing assembly of the valve. If the leak is detected when the valve is closed then it is actuated from the valve. additional way in the sense of dinner, for example, until the leak, and thus the vibration, disappears.

BRIEF DESCRIPTION OF THE INVENTION It is an object of the invention to provide a double seal valve with an improved valve state monitoring system. It is another object of the present invention to provide an improved method of monitoring the operational status of a double seal valve.

In a first aspect, the invention can be said in a crude manner as a valve apparatus comprising: (a) a valve with a valve body with a first and second valve chambers connected to respective valve ports and connected by an intermediate passage, the valve being selectively configured in: i a first open configuration in which the intermediate passage is open and the first and second valve chamber are interconnected by the intermediate passageII a second closed configuration in which the intermediate passage is closed by first and second seals seated in respective places in the passage to seal respectively between the first and second valve chambers and a first leak chamber in the portion of the intermediate passage between the two stamps, or ni. a third cleaning configuration in which one of the two seals is in a bad position to connect one of the respective first or second valve chambers to the first leak chamber, while the other of the two seals remains seated, (b) a valve actuator adapted to establish the valve in any of the three configurations in response to respective control signals, and (c) a flow sensor connected to the first leak chamber and adapted to provide a flow sensor output signal that is indicative of a leakage flow of the first leakage chamber Preferably, the valve apparatus further comprises a valve controller with at least one signal input port in which the output stream signal of the sensor is connected, and the The valve controller is adapted to provide at least one control signal to the valve actuator to locate the valve in any one of three configurations. respond to the output signal of the flow sensor and make a comparison between the leakage flow as indicated by the output signal of the flow sensor and a predetermined flow from the first leakage chamber associated with the selected valve configuration , and provide an output signal from the controller that is sensitive to the comparison and is indicative of the presence or absence of a desired valve function or undesirable valve dysfunction.The output signal from the controller may be indicative of an undesirable valve dysfunction when the valve is in the second closed configuration, the dysfunction being a leak flowing from either the first or second valve chamber, through the respective first or second seals and inside the first leak chamber Alternatively or additionally, the output signal of the controller may be indicative of a desirable valve function when the valve is in the third configuration of cleaning the desirable function of valve being an inlet flow. -ves of the seal not seated from a respective valve chamber within the first leakage chamber The valve may have a third seal located between the first and second seals, the third seal being to seal the first leak chamber from the valve chambers and the interconnected passage when the valve is in the first open configuration. Preferably, the output signal from the controller is indicative of an undesirable valve dysfunction, when the valve is in the first open configuration, and the dysfunction is a leak flowing through the third seal and into the first leak chamber, starting from the first and second interconnected valve chamber and the interconnected passage Preferably, the first and second seal can be mounted on respective first and second valve members; the first and second and first valve members are independently movable relative to the valve body to cause the selected valve configuration, the valve apparatus further comprises a second leak chamber between the first valve member and the body, a fourth seal for sealing between the first valve member and the valve body, the fourth seal being located between the first valve chamber and the second leak chamber, a third leak chamber between the second valve member and the valve body, and a fifth seal for sealing between the second valve member and the valve body; the fifth seal being located between the second valve member and the third leakage chamber; and the second and third leakage chambers being connected to the flow sensor so that leakage flows through the fourth seal and into the second leakage chamber, or through the fifth seal and into the third chamber, is directed to the sensor of flow so that the output signal of the sensor can also be indicative of the leakage flow through the fourth or fifth seals.

Preferably, the output signal from the controller is indicative of an undesirable valve dysfunction when the valve is in the first 'open' configuration or the second 'closed-off' configuration and the malfunction is a leakage flowing from the first valve chamber and through the fourth seal inside the second leak chamber, or a leak flowing from the second valve chamber and through the fifth seal into the third leak chamber The flow sensor can have a tubular passage and a pair of annular electrodes mounted coaxially with, and spaced far apart, from an electrically insulated wall of the tubular passage, the flow sensor being connected to the first leak chamber in a manner that the leakage flows from the first leakage chamber through the tubular passage and all along the electrodes to provide an electrically conductive passage between them.

In a second aspect of the invention, this can be roughly explained as a method of monitoring the status of a controlled valve having a valve body and a first and second valve chamber connected to respective valve ports and joined by passages intermediaries, the valve being selectively confi-able in: i. a first open configuration P in which the intermediate passage is open and the first and second valve chamber being interconnected by the intermediate passage, ii. a second 'closed' configuration in which the passage is closed by first and second seals seated in respective places in the passage to be sealed respectively between the first and second valve chamber and a first leak chamber in the portion of the intermediate passage between two stamps, or ni. a third configuration of 'cleaning' in which one of the two seals does not seat to connect respectively one of the first and second valve chamber to the first leak chamber, while the other of the two seals remains seated, the method comprising the steps of (a) connecting a flow sensor to the first leak chamber, the flow sensor provides a flow sensor output signal that is indicative of a leakage flow from the leak chamber, (b) receiving a signal and selectively setting the valve to one or other of the three configurations in response to the received control signal; (c) comparing the leakage flow as indicated by the output signal of the flow sensor with a predetermined flow from the first leak chamber associated with the selected configuration of the valve, and (d) providing a comparison output signal that is reflective of the comparison and is indicative of the presence or absence of a function of the of the valve or an indeterminate valve dysfunction The comparison output signal provided in step (d) can be indicative of a valve dysfunction when the valve is in the second closed configuration, the dysfunction being a leakage flow from the first or second valve chamber , through the respective first or second seal and within the first leak chamber Alternatively or additionally, the comparison output signal provided in step (d) may be indicative of a desirable valve function when the valve is in the third 'cleaning' configuration, the desired function of valve being a flow through the seal not seated from a respective valve chamber into the first leak chamber Preferably, the valve has a third seal located between the first and second seal, the third seal being to seal the first leak chamber from the interconnected valve chambers and the connected passage or the valve is in the first 'open' configuration, and the dysfunction is a leak flowing through the third seal and into the first leak chamber, from the first and second valve chambers and the in-connected passage Preferably, the first and second seal are mounted on respective first and second valve members; the first and second valve members move relatively independently of the valve body to effect the selected valve configuration, the valve further comprising a second leak chamber between the first chamber member and the body, a fourth seal for sealing between the first chamber member and the valve body, the fourth seal located between the first valve chamber and the second leak chamber, a third leak chamber between the second valve member and the valve body, and a fifth seal to seal between the second valve member and the valve body, the fifth seal being located between the second valve chamber and the third leakage chamber, and the second and third leakage chambers are connected to each other. the flow sensor so that the leak flows through the fourth seal and into the second leak chamber, or through the fifth seal and into the third leak chamber, is directed to the flow sensor so that the The output signal of the flow sensor will also be indicative of a leakage flow going through the fourth and fifth seals. The comparison output signal may be indicative of undesirable valve dysfunction when the valve is in the first 'open' configuration or the second 'closed' configuration, where the dysfunction is a leakage flow from the first valve chamber and passing through the fourth seal into the second leak chamber, or a leakage flow from the second valve chamber and passing through the fifth seal into the third leak chamber.

The flow sensor can have a tubular passage and a pair of annular electrodes mounted coaxially with, and spaced along, an electrically insulated wall of the tubular passage, and the flow sensor is connected to the first leak chamber so that the leak flows from a leakage chamber flow through a tubular passage and transversely to the electrodes to provide an electrically conductive passage between them BRIEF DESCRIPTION OF THE FIGURES The aforementioned and other objects of the invention, features and advantages of the present invention will now be described in greater detail with reference to the preferred embodiment and reference of the accompanying drawings in which: Figure 1 shows a partially cross-sectional view of a valve system according to an embodiment of the invention, and Fig. 2 shows a cross-sectional view of a flow sensor for use as a part of the valve system of Fig. 1 DETAILED DESCRIPTION OF THE INVENTION Through the drawings and description, the same or corresponding elements are indicated or referred by the same numerical reference Although a valve system is shown and described with a valve and actuator in a vertical orientation, it is understood that this particular orientation has been shown and described generally for the convenience and clarity of the description, and that the invention is not limited. to such orientation Figure 1 shows a partially cross-sectional view of a valve system according to a preferred embodiment of the invention. The valve system comprises a valve 1 and an integral valve actuator 2 which is shown in quarter cross section view, the left side shows the outside of the valve and actuator, and the right side shows a cross sectional view as it is seen in a plane through the longitudinal axis (for example vertical axis) of the valve and actuator. Figure 1 also schematically shows parts of the system that are external to the valve and actuator The valve and actuator are generally symmetrical on the longitudinal axis, except when this is not convenient (as will be noted below) A sensor 3 is fitted to the lower end of the valve The valve and actuator have a common body 4, a lower portion of which houses two valve chambers a first valve chamber 6 and a second lower valve chamber 8. In the embodiment shown in figure 1, the valve chamber supepor opens to a left side port 10 and to a right side port 16 In another embodiment the valve may have another number of ports, for example only one port for either or both of the lower and upper valve chambers, or more than two ports for one or both of upper and lower valve chambers.

The two valve chambers 6, 8 are connected by an intermediate passage 18 which is circularly cylindrical and coaxial to the body of the valve.

The valve has a first valve member or piston 22. The pistons slide axially in the valve body 4 with the second piston 22 sliding generally along the axis of the body and the first coaxial piston 20 around an upper piston, but not the more superior, part of the first piston.

A top, or first, main seal 24 is supported around the outer circumference of the first plunger 20 near the lower end of this plunger. A lowermost, or second, main seal 26 is supported around the outer circumference of the second plunger 22 in a middle portion of this plunger. The pistons can be independently moved in an axial direction relative to the valve body 4 to seat the two main seals against the cylindrical wall of the intermediate passage 18. A first leak chamber 28 is located between the first and second main seal 24, 26 as will be described with more information abaio The first plunger 20 slides in an upper pair of circular body seals spaced apart from each other 30, 32 fitted to a wall within an upper portion of valve body 4. A second leakage chamber 34 is formed between the first piston and the body of valve 4 and between these two circular body seals 30, 32.

The second plunger 22 slides in a lower pair of circular body seals spaced apart from one another 36, 38 fitted to a wall within a lower portion of the valve body 4. These lower body seals 36, 38 provide a seal between the second releasable plunger 22 and the valve body 4. A third leak chamber 40 is formed between the second plunger and the valve body 4 and between these two lower body seals 36, 38 A third main valve seal 42 is adjusted inwardly from a lower end face 44 of the first plunger 20. This third main valve seal can be seated against a shoulder 46 that looks down from the second plunger 22 to close an outer perimeter of a portion of the first leak chamber 28 between the end face 44 and the shoulder 46 The valve is shown in Figure 1 in a 'closed' configuration in which both the first and the second main valve seals 24, 26 are seated in the intermediate passage 18 to isolate the first and second valve chamber 6, 8 from another and the first leak chamber 28 which is sealed from the second valve chamber 8 by the second main valve seal 26. With the first leak chamber 28 intervening between the two valve chambers, any leakage that passes any of the two main seals 24, 26 flowing into the valve chamber 28, which being vented to the atmosphere as will be better explained later, avoiding cross-contamination between the valve chambers when the valve is in the closed configuration shown in Figure 1 This closed configuration is the immovable valve configuration.

The upper end of the valve body 4 houses the actuator 2. In the embodiment shown in figure 1, the valve is actuated by application of pneumatic or hydraulic pressure to control the ports 50, 52, 54, to control the axial sliding movements of the two pistons 20, 22, as will now be discussed. However, the valves can be actuated by other means of motion, for example by means of electric motors. The two valve pistons are inclined by coil springs, not shown, which return the pistons to the 'closed' configuration by releasing the fluid pressure applied to the control ports When the pressure is applied to the first control port 50, the first plunger 20 is pushed down causing the third seal 42 on the low end face 44 of the first plunger to seat against the downwardly directed shoulder 46 of the second plunger 22 and in this way seal around the outer perimeter of the first leak chamber 28 The further downward movement of the first piston increases the set pressure of the third seal on the second piston and thereby bring the second piston down to stop seating the second piston. main seal 26 of the lower end of the intermediate passage 18. Further downward movement of the first plunger brings the first main seal 24 down through the intermediate passage, eventually causing the first major seal 24 not to seat at the lower end of the passage intermediary and thus push the valve into an 'open' configuration in which the first and second valve chamber 6, 8 are freely interconnected by the intermediate passageway 18. In this open configuration, a tapered waist 55 near the lower end of the first plunger 20 reaches the intermediate passage 18 to provide open interconnection between the first and second valve chamber 6. , 8 As noted below, the valve returns to the stationary 'closed' configuration when the pressure applied to the first control 50 is released When the pressure is applied to the second control body 52, the first plunger 20 is moved upwards causing the first main seal 24 to stop sitting on the upper end of the intermediate passage 18, and thereby connecting the first valve chamber 6 with the first leak chamber 28 This action does not move the second plunger 22 from its still position, then the second main seal 26 remains seated in intermediate passage 18 This first configuration of 'cleaning', a cleaning fluid flows through the first valve chamber flowing past the first main seal 24 and the third seal 42 to flow into the first leak chamber 28 In this way the first valve chamber 6 and these two seals 24, 42 can be washed with the cleaning fluid while the second valve chamber 8 remains sealed by the second main seal 26 of the cleaning fluid Similarly, when the pressure is applied to the third control port 54, the second plunger 22 is pushed down causing the second main seal 26 to stop being seated at the lower end of the intermediate passage 18, and thereby connect the second valve chamber 8 with the first leak chamber 28 This action does not moving the first plunger 22 from its still position, then the first main seal 24 remains seated in the intermediate passage 18 In this second cleaning configuration, a cleaning fluid flows through the second valve chamber past the second main seal 26 and the third seal 42 for flowing into the first leak chamber 28 In this way the second valve chamber 8 and these two seals 26 42 can be washed with the cleaning fluid while the first valve chamber 6 remains sealed by the first main seal 24 of the cleaning fluid.

The first leak chamber 28 is vented to the atmosphere by an axial drain bore 56 at the bottom of the second valve plunger 22. This lower end of the drain bore terminates at a first leak port 58 The leak flows into the the first leak chamber 28 (for example passing the first or second valve main seal 24, 26 when the valve is in the 'open' configuration, or the cleaning fluid is spilled by passing the respective main seal 24, 26 and the third seal 42 in the first or second 'cleaning' configuration) flowing downward toward the drain bore 56 to pour from the borehole to the first leak port 58.

The valve pistons, and the valve body cavities in which they slide, are preferably circular in cross section. Similarly, the seals are also circular. In general, as noted above, the valve and actuator are generally symmetrically circular about the longitudinal axis. The exceptions include the valve ports 10, 12, 14 and 16, and the control ports 50, 52, 54, which are generally aligned in respective radial directions and which can be conveniently provided as threaded holes aligned along the a radius to the longitudinal valve shaft In the preferred embodiment shown in Figure 1, a funnel hole is fixed to a circumferential ridge 62 around the lower end of the valve body 4 by a clamp 64. The funnel is sufficiently elongated to be accommodated to the first leak port 58 when the second plunger 22 is in its lowest position, as when the valve is in the 'open' configuration.

Figure 1 shows an exterior view of the flow sensor 3 fitted to the low end of the funnel 60. As it is best appreciated from Figure 2, which shows a cross-sectional view of the flow sensor, the flow sensor is generally cylindrical and has a passage 66 through it, cylindrical and axially aligned.

The sensor 3 has a neck 68 in the upper base with a cylindrical groove 70 by which the sensor is fitted to a cylindrical spout at the low end of the funnel 60 A screw 72 fixes the neck around the spout An electrically insulated annular collar 74 is fitted in a lower cylindrical groove in the base the collar 68 An annular conductive electrode 76 is fitted in a groove in the low end of the first insulated collar 74. A lower insulated electrically annular collar 78 is fitted to the low end of the annular electrode. annular circuit 80 surrounds, and is supported by, the lower insulated collar. The circuit board is populated by electronic components, one of which is a light-emitting diode (LED) 82 to provide a local indication to facilitate troubleshooting and the purpose of finding faults.A preferred arrangement, not shown, includes three LEDs spaced equidistantly to give visual indication of 360 degrees in sensor location A stainless steel housing 84 is fitted to the lower end of the collar base to surround and thereby house the insulated collars, the electrode, the circuit board, and the LEDs. The vacuum between the isolated electrodes and the housing is filled with a material 86 for electrically insulating encapsulation. A connector 88 mounted on the tubular housing 84 provides a connection to the sensor circuitry for supplying electrical power to the sensor and for connecting an output signal from the sensor to a remote system The innermost walls of the base collar 68, the lower insulated collars and and the electrode is each circularly cylindrical and of substantially the same diameter. These walls together define the cylindrical passage 66.

The base collar, the screw, the electrode and the housing are preferably made of stainless steel, and in the preferred embodiment SS304 in the case of the base collar, the screw and the electrode, and sss 316 in the case of the housing Alternatively, these parts can made of any other material that is appropriate for use with the process and cleaning fluids to be handled by the valve The lower and upper insulated collars are preferably made of a material that resists moisture for the process and cleaning fluids to be handled by the valve. In a preferred embodiment, the insulated collars are made of a hydrophobic, chemically inert material, and preferably polytetraf Luo-Roethylene (PTFE) The use of PTFE for insulated collars reduces the sensitivity of the sensor to conditions where moisture is present but does not flow through the sensor When a sufficient flow of liquids flows down the wall of passage 66 and provides an electrically conductive bridge between the base collar as a sensing electrode and the annular electrode, the electronic circuit provides an output signal indicating this flow, in the connector 88 A local indication is also provided by LED 82 Thus the sensor provides a signal that is responsive to a flow from the first leak chamber via the drain bore 56, the first leak port 58 and funnel 60 through the passage 66 in the flow sensor. The funnel 60 is provided with openings 89 to release excess flow that can not quickly pass through the passage of the flow sensor 66. It is understood that while the fluid passes the valve there may be a gas or a gas / liquid mixture, this may result in a flow of liquid through the sensor. For example, when steam is used to clean the valve, the flow in the sensor may be a condensate in liquid form.

The sensor output is connected through the connector 88 via a signal line 90 to an input port of a control valve and a monitoring system 91. The control and monitoring system provides control signals in the control lines respective 92, 94, 96 for respective control ports 50, 52, 54 of the valve actuator 2 to establish any of the configurations in the valve. In a typical application the control and monitoring system preferably includes a PLC, a SCADA or any computer or control based on a microprocessor and monitoring system The output signal from the sensor is compared by the monitoring and control system 91 with a signal representative of the control signals sent to command the valve actuator 2 to cause the valve to acquire a selected configuration. The control and monitoring system makes a comparison between the flow of the fluid through the sensor 3 as indicated by the sensor output signal, and a predetermined desired flow from the first leak chamber 28 via port 58, associated with the selected valve configuration . The control and monitoring system then provides a signal that is the response to the comparison and is indicative of the presence or absence of a desired valve function or undesirable valve dysfunction. The output signal can be sent to a remote location to provide an indication of the presence or absence already indicated to an operator. Alternatively, when the valve is part of a process plant, the control system of the plant can be made sensitive to the output signal that indicates the absence or multi-mentioned presence In a first example, when the valve is in the open configuration ', the predetermined desired flow from the first leak chamber 28 to the sensor 3 as associated with this configuration is a zero flow, as would be expected when there is no leakage passing the third valve seal 42 If the sensor signal indicates a flow when the valve is in this configuration, the control and monitoring system provides an output signal indicating this as a valve malfunction. Conversely, if the sensor signal indicates a non-flow when the valve is in this configuration, the system provides an output signal confirming the desired valve function. In a second example, when the valve is in a "closed" configuration, the predetermined desired flow from the first leak chamber 28 to the sensor 3 as associated with this configuration is zero flow as would be expected when there is no leakage through the main valve seals 24, 26. If the signal from the sensor indicates a flow when the valve is in this configuration, that is to say there is a leak flowing from the first or second valve chamber 6, 8, passing through the respective first or second main seals 24, 26 and inwards of the first leak chamber 28, the system 91 provides an output signal indicating this as a valve dysfunction. Conversely, if the sensor signal indicates no flow when the valve is in this configuration, the system provides an output signal confirming the desired valve function.

The scope of the leakage and flow monitoring provided by the system can be easily extended as will now be described. A fluid flow conduit 100, connected to a leak port 102 fed from the second leak chamber 34, is connected to a leak port 104 by feeding into the interior of the funnel 60. On this path, leak passing the seal of the upper body 30 within a second leak chamber 34, flows into funnel 60 and thus down through flow sensor 3 Similarly, a fluid flow conduit 106, connected to a leak port 108 constructed from a second leak chamber 40 is connected to port 104 leading to the interior of funnel 60. On this path, the leak passes the seal of lower body 36 into the second leak chamber 40 which flows into funnel 60 and thus down through the flow sensor 3. The conduits 100, 106 may be connected together and thus to a common port 104 leading to the interior of the funnel as described above and as shown in Figure 1, or may be coupled independently to respective ports. With these additional conduits, leaks from the first or second valve chambers 6, 8, pass respective body seals 30, 36 into second and third leakage chambers 34, 40, are detected by the sensor 3 It can be noted that the monitoring of the described valve can provide indications of a plurality of valve conditions using a simple flow sensor. It can also be noted that, for convenience of illustration, Figure 1 shows port 104 directly above the openings. However, in practice a drainage opening will not be located directly below port 104 so that the flow of fuel introduced into the funnel in port 104 does not flow down.

However, some ambiguities can result from a flow in the sensor in any of the configurations, at least in some cases this can be resolved by waiting until the valve is placed in one or more configurations and correlating the presence of the flow in the sensor with the additional configurations In some circumstances any ambiguity can be solved by correlation of the flow detected in the sensor with the known presence and pressure of fluids in particular valve chambers for particular configurations Even with some ambiguities, the system is useful since it can be used to confirm correct flows of clean-i n-p lace fluids when the valve is in a 'cleaning' configuration and to confirm the absence of leaks by passing the seated seals, in an 'open' and 'closed' configuration An early indication of seal failure or system may be provided, In contrast to the visual indications known on the valves (such as those provided by the discharge of the flow from the first leak port 58) , the indication provided by the valve system described above and shown in Figure 1 may be relegated to a remote monitoring location and used to modify the control of the process in which the valve system is serving It is understood that the invention is not limited to a particular valve topology described above, which is given as a reference by way of example. The combination of flow sensor and double valve seal can be applied to other double seal valve topologies. without departing from the scope of the invention. For example, the invention can be applied to a double seal valve in which both valve pistons are operated from below. Such valves are typically used to control inlet and / or outlet flows in the base of a tank or similar container.

A preferred embodiment application of the invention is in association with hygienic mixing test valves (for example double seal) used in food processing, for example milk products, where early warning of seal failure and confirmation of correct cleaning It is very important to avoid any risk of contamination by intermingling of food and cleaning liquid However, the preferred embodiment has been described with reference to the conductivity sensor, another array of sensors can provide a signal indicating the presence or absence of flow, and can be used in cases where the fluid has low conductivity. For example, an alternative sensor can use electrical capacitance The term 'comprising' as used in this description and claims 'consists of at least a part of', that is to say when the interpretation of the specifications is made. LIST OF CHARACTERISTICS LABELED IN THE FIGURES Valve 1 Valve actuator 2 Sensor 3 Valve body 4 First valve chamber (upper) 6 Second valve chamber (lower) 8 Left side port of upper valve chamber 10 Right side port of upper valve chamber 12 Left side port of lower valve chamber 14 Right side port of lower valve chamber 16 Intermediate passage 18 First valve piston 20 Second valve piston 22 First main seal (lower) 24 Upper main seal (second) 26 First leak chamber 28 Upper body seals 30, 32 Second chamber leakage 34 Lower body seals 36, 38 Third leakage chamber 40 Third major seal 42 Lower end face (of the first piston) 46 First control port 50 Second control port 52 Third control port 54 Waist 55 Drain bore 56 First leak port 58 Funnel 60 Circumferential ridge 62 Clamp 64 Passage 66 Base collar 68 Cylindrical top groove 70 Screw 72 First ring collar isolated 74 Electrode 76 Second ring collar isolated 78 Circuit board 80 LED 82 Housing 84 Encapsulation material 86 Connector 88 Drainage openings 89 Signal lines 90 Control and monitoring system 91 Control lines d the actuator 92 94, 96 Duct 100 Second leak port 102 Funnel port 104 Conduit 106 Third leak port 108

Claims

R E I V I N D I C A C I O N S

A valve apparatus comprising: (a) a valve (1) having a valve body (4) with first and second valve chambers (6, 8) connected to respective ports (10 and 12, 14 and 16) and joined by an intermediate passage (18), the valve being selectively configured in: i a first 'open' configuration, in which the intermediate passage is open and the first and second valve chamber are connected by the intermediate passage, n. a second 'closed' configuration in which the passage is closed by first and second seals (24, 26) seated in respective places in the passage to be sealed respectively between the first and second valve chamber and a first leak chamber (28) in the portion of the intermediate passage between the two seals, or a third configuration of 'cleaning' in which one of the two seals does not seat to connect respectively one of the first and second valve chamber to the first leak chamber, while the other of the two seals remains seated, (b) a valve actuator (2) adapted to establish the valve in any of the three configurations in response to respective control signals, and (c) a flow sensor (3) connected to the first leak chamber and adapted to provide a flow sensor output signal that is indicative of a leakage flow of the first leak chamber.
2. The valve apparatus as claimed in claim 1, further comprising a valve controller (91) having at least one signal input port (90) to which the output signal of the flow sensor is connected, where the controller The valve is adapted to: provide at least one control signal (92, 94, 96) to the valve actuator to confer on said valve one of the three configurations; answering the output signal of the flow sensor and making a comparison between the leakage flow as indicated by the output signal of the flow sensor and a predetermined flow from the first leakage chamber associated with the selected valve configuration, and providing a controller output signal for comparison and indicating the presence or absence of a desired valve function or undesirable valve dysfunction.
3 The valve apparatus as claimed in claim 1, wherein the output signal from the controller is indicative of undesirable valve dysfunction when the valve is in the second closed configuration, the dysfunction being a leak flowing from the first or the second valve chamber, passing the respective first and second seals and into the first leak chamber.
4. The valve apparatus as claimed in claim 1, wherein the output signal of the controller is indicative of a desirable valve function when the valve is in the third configuration 'cleaning', the desired valve function being a flow passing through the seals not seated from the respective valve chamber and into the first leakage chamber
5. The valve apparatus as claimed in claim 1, wherein the valve has a third seal (42) located between the first and second seals, the third seal being to seal the first leak chamber from the interconnecting valve chambers. and the passage that interconnects when the valve is in the first 'open' configuration
6 The valve apparatus as claimed in claim 5, wherein the output signal from the controller is indicative of undesirable valve dysfunction when the valve is in the first 'open' configuration, the dysfunction being a leak flowing past the third seal into the first leak chamber, from the first and second valve chamber and the passage that connects them
7 The valve apparatus as claimed in claim 1, wherein the first and second seals (24, 26) are mounted on respective first and second valve members (20, 22), the first and second valve members are independently moved relative to the valve body (4) to effect the selected valve configuration, the valve apparatus further comprising a second leak chamber (34) between the first valve member and the body, a fourth seal (30) for sealing between the first valve member and the valve body, the fourth seal being located between the first valve chamber (6) and the second leak chamber (34), a third leak chamber (40) between the second valve member member (22) and the valve body (4), a fifth seal (36) for sealing between the second valve member and the valve body, the fifth seal being located between the second valve chamber (8) and the third leakage chamber, and the second and third leakage chambers (34, 40) are connected to the f sensor luxury (3) so that the leakage flow passes the fourth seal (30) and enters the second leakage chamber (34), or passes the fifth seal (36) and enters the third leakage chamber (40) , and is directed to the flow sensor so that the sensor output signal can also be indicative of a leakage flow for the fourth or fifth seal
8. . The valve apparatus as claimed in claim 7, wherein the output signal from the controller is indicative of undesirable valve dysfunction when the valve is in the first 'open' configuration or the second 'closed' configuration and dysfunction it is a leak flowing from the first valve chamber passing the fourth seal into the second leak chamber and passing the fifth seal into the third leak chamber
9. The valve apparatus as claimed in claim 1, wherein the flow sensor (3) has a tubular passage (66) and a pair of annular electrodes (68, 76) mounted coaxially with and spaced from, an insulating wall electrically from the tubular passage, the flow sensor is connected to the first leak chamber (28) so that the leakage flow from the first leak chamber (28) flows through the tubular passage and tangentially to the electrodes to provide a electrically conductive path between them
A method of monitoring the status of a control valve (1) having a valve body (4) and a first and second valve chambers (6, 8) connected to respective valve ports 10 and 12, 14 and 16) and joined by an intermediate passage (18), the valve being selectively configured in a first 'open' configuration, in which the middle passage is open and the first and second valve chamber are connected by the intermediate passage, II a second 'closed' configuration in which the passage is closed by first and second seals (24, 26) seated in respective places in the passage to be sealed respectively between the first and second valve chamber and a first leak chamber (28) in the portion of the intermediate passage between the two seals, or a third configuration of 'cleaning' in which one of the two seals does not seat to connect respectively one of the first and second valve chamber to the first leakage chamber, while the other of the two seals remains seated, the method comprising the steps of: (a) connecting a flow sensor (3) to the first leakage chamber, the flow sensor thereby providing a signal of exit that is indicative of a leakage flow from the first leakage chamber; (b) receiving a flow control signal (92, 94, 96) and selectively placing the valve in any of the three configurations in response to the received control signal; (c) comparing the leakage flow indicated by the sensor output signal with a predetermined flow of the first leakage chamber associated with the selected valve configuration, and (d) providing a comparison output signal that is sensitive to the comparison and is indicative of the presence or absence of a desirable valve function or an undesirable valve dysfunction
11. A monitoring method as claimed in claim 10, wherein the comparison output signal provided in step (d) is indicative of an undesirable valve dysfunction when the valve is in the second "closed" configuration, the dysfunction a leak being flowing from the first or second valve chamber, passing the respective first or second seals and into the leak chamber.
12. A monitoring method as claimed in claim 10, wherein the comparison output signal provided in step (d) is indicative of a desirable valve function when the valve is in the third configuration 'cleaning', the function desirable being a flow passing through the seal not seated from a respective valve chamber into the first leakage chamber
13. A monitoring method as claimed in claim 10, wherein the valve has a third seal (42) located between the first and second seals, the third seal being to seal the first chamber of the first leak chamber from the chambers of interconnected valve and the interconnection passage when the valve is in the first 'open' configuration
14. A monitoring method as claimed in claim 13, wherein the comparison output signal provided by the valve controller is indicative of an undesirable valve dysfunction when the valve is in the first 'open' configuration, and the dysfunction it is a leak flowing past the third seal and into the first leak chamber, from the first and second interconnected valve chambers and the interconnection passage
15. A monitoring method as claimed in claim 10, wherein the first and second seal are mounted on respective first and second valve members (20, 22); the first and second valve members are movable independently in relation to the valve body to carry out the selected valve configuration, the valve further comprising a second leak chamber (34) between the first member and the body; a fourth seal (40) for sealing between the first valve member and the valve body, the fourth seal being located between the first valve chamber (6) and the second leak chamber (34), a third leakage chamber (40) between the second valve member member (22) and the valve body (4) and, a fifth seal (36) for sealing between the second valve member and the valve body, the fifth seal being located between the second valve chamber (8) and the third leak chamber; and the second and third leakage chambers (34, 40) are connected to the flow sensor (3) so that the leakage flow passes the fourth seal (30) and enters the second leakage chamber (34), or pass the fifth seal (36) and enter the third leakage chamber (40), and be directed to the flow sensor so that the sensor output signal can also be indicative of a leakage flow past the fourth or fifth seal . A monitoring method as claimed in claim 15, wherein the comparison output signal is indicative of an undesirable valve dysfunction when the valve is in the first 'open' configuration or the second 'closed' configuration, and dysfunction is a leak flowing from the first valve chamber and passing the fourth seal into the second leak chamber, or a leakage flow from the second chamber and passing through the fourth seal into the second leak chamber, or a leak flowing from the second valve chamber and passing the fifth seal into the third leak chamber A monitoring method as claimed in claim 10, wherein the flow sensor (3) has a tubular passage (66) and a pair of annular electrodes (68, 76) coaxially mounted with, and spaced from , an electrically isolated wall of the tubular passage, and the flow sensor is connected to the first leak chamber (28) so that the leakage flow from the first leak chamber flows through the tubular passage and transversely over the electrodes to provide an electrically conductive passage between them. SUMMARY A valve apparatus has a valve (1), a valve actuator (2), having a valve body (4) with first and second valve chambers (6, 8) connected to respective ports (10 and 12, 14). and 16) and joined by an intermediate passage (18), the valve being selectively configured in any of three configurations. A first 'open' configuration, in which the intermediate passage is open and the first and second valve chamber are connected by the intermediary passage; a second 'closed' configuration in which the passage is closed by first and second seals (24, 26) seated in respective places in the passage to be sealed respectively between the first and second valve chamber and a first leak chamber (28) in the 15 portion of the intermediate passage between the two seals, or a third configuration of 'cleaning' in which one of the two seals does not seat to connect respectively one of the first and second valve chamber to the first leak chamber, while the another of the two seals remains settled. A flow sensor (3) 20 connected to the first leak chamber and adapted to provide a flow sensor output signal that is indicative of a leakage flow of the first leakage chamber ~ > s