GB2386392A - Plumbing system with isolation valve and system drainage - Google Patents

Abstract

A plumbing system has a power-actuated isolation and shut-oft valve (14), for selectively operable shut-off, using a remote switch control (20) and system drainage upon shut-off through what was a feed route (12) in normal operation.

Description

Remote Valve 5 This invention relates to remote control valves and is

particularly, but not exclusively, concerned with a remote control valve for a [domestic] [mains] water supply.

Terminology 10 The term 'valve' is used herein to embrace any form of flow controller, diverter, regulator or switch.

The term 'remote' reflects [some] distance between a valve, with associated valve member actuator and a valve function control [switch].

Editorial For conciseness, terms in brackets, vis [...], reflect optional features, qualifiers, or characteristics. Background

A typical domestic cold water mains supply feed features a manual shutoff valve, or stop cock, at or adjacent an entry to a property.

More specifically, an outside, property-specific, stop-cock - primarily for a utility provider or emergency services - is installed at an interface with a water distribution network. 30 In addition, an internal stop-cock is fitted at an initial point of entry into the property.

This internal stop cock enables a downstream distribution or circulation system and attendant plumbing ware and water consumption appliances to be isolated from an upstream mains supply.

Individual appliances may be fitted with respective shut-off valves, but these are primarily for installation, maintenance and repair and are localised and light duty.

An internal stop-cock represents a primary supply [manually-operable] control and is 40 commonly a robust, heavy-duty mechanism.

One construction employs a rotary threaded valve sleeve and sliding plunger stem -

and valve member operation requires a succession of several ['T'] handle turns, between fully on and fully off positions.

With close component clearances and internal seals, glands and packing to inhibit leaks under high operating pressure - valve action can be quite stiff, particularly initially with swelling and stiffening.

50 Moreover, even though typically of brass construction, valves can become corroded and even seized, such as with internal lime scale deposits.

Valve seizure is aggravated by lack of regular use, or rotary valve sleeve lubrication.

That is, consumers do not regularly 'cycle' [that is repeatedly turn from ON to OFF and vice-versa] their property stop cock valves, as a check upon freedom of operation.

Thus stop valves can prove obstinately stiff and resistant to operate promptly in an emergency situation - such as a burst pipe.

Moreover, stop cock location can be inaccessible or unknown to a person faced with 10 an emergency.

Prior Art

There have been various proposals for remote control valves - some with automatic 15 operation - to replace, or supplement, manual stop cocks. Thus: EP0051374 features an automatic control valve with a water flow detector.

US4889313 teaches a remotely operable valve for utility services, such as gas and 20 water, with a spring-loaded latch with ring pull actuator.

US5076321 addresses a flow sensitive, fluid shut-off valve, operable upon perceived (by an opto-electronic sensor) overly high water consumption in a building water supply. A so-called WATER COP (Trade Mark) has also been devised by Dynaquip Controls Corporation of Missouri, USA and features wireless leak detection and automatic water shut-off.

30 A non-electric, water pressure operated, remote and local direct water switch branded SURE STOP (Trade Mark) has also been made available by Sure GB Ltd of Solihull, UK. Yokata Manufacturing Co Ad., at aquadevice. com, has also contrived a pilot valve with 35 an emergency shutoff facility upon detection of abnormal modes, such as attendant pipe rupture. Relative inlet and outlet pressures and through flow are monitored.

These devices have not addressed the entirety of the external water supply and internal content.

Thus, even if a system is isolated from a mains supply, several tens of gallons of water remain in the low pressure, hot water side - from a cold water header tank through a hot water tank and associated pipework.

45 Traditionally, there is no means of draining the hot water side except by manually opening hot water taps at the lowest [ground floor] level and letting water drain away through individual sink, basin or bath waste outlets.

A failure, such as a rupture or burst pipe, in the low pressure, hot water side is not 50 immediately relieved by mains isolation.

Rather, considerable water damage can still accrue, until the entire hot water system

contents have spilled over the property, with attendant damage.

Nor does the art identified address pipe failure in a central heating [system] circuit where again the internal system contents could cause damage if discharged.

That is, the art neither provides feed isolation nor drainage for a central heating circuit.

Remote actuated valves are also known, for heat zone selection, in domestic hot water systems, selectively to control certain radiator groups, but generally operate at 1 0 lower system pressures, such as from a cold water gravity header tank.

An exception would be mains primed combination boiler systems - which are protected by low pressure and over-pressure boiler shut-off or inhibit systems.

15 However, the radiator system generally remains at mains pressure, and in any event the system contents are significant if discharged.

Low pressure central heating and hot water system valves are commonly of a sliding gate internal valve member construction - also vulnerable to lime scale build up, 20 corrosion and seizing - exacerbated by infrequent usage.

Generally, remote actuated mains shut-off or isolator valves have not been widely adopted, either for new installations, or as after-market, retro-fit, accessories.

Statement of Invention

Plumbing System 30 According to one aspect of the invention, a plumbing system incorporates an emergency shut-off or isolator valve, for isolating the system, from both: 35 À a remote mains feed; and À a local water header tank.

Conveniently, the system also features 40 a [selectively operable] diversion path, for system drainage; [once the mains has been isolated] through a former pathway of the now isolated mains feed.

A multi-function valve may integrate mains isolation and system contents drainage roles in selective operation.

As a fail-safe precaution, the valve could be biassed nominally closed requiring 50 actuator operation to enable mains feed, or indeed system drainage.

A combination of mechanical spring and water pressure could be used to provide

such bias.

In a particular construction, a valve with an integral actuator, such as a solenoid, would be fitted at or adjacent an entry point of a mains water feed pipe into a property.

Thus the actuator valve could supplement or - given a manual over-ride facility - even replace an existing conventional manual stop-cock.

A control [switch] would be installed at a visually prominent and conveniently 10 accessible location - such as at waist or eye level, in a kitchen or hallway.

For convenience and immediacy of operation in an emergency, such a control switch could be configured as prominent, [single] push action, panic button, requiring only modest operating pressure.

Such a button could be illuminated at night - such as by an electroluminescent backplate or striker face.

The control [switch] and solenoid valve could be interconnected by an umbilical 20 electrical cable.

The cable could be of low current duty or capacity and thus thin gauge the solenoid then being supplied with a heavy duty, high current mains feed directly at its location.

25 A relay could allow low current signals from the actuator switch to determine connection of high current from a mains supply to energise the solenoid.

An audio and/or visual indicator on the control - and/or indeed the actuator valve itself - could reflect valve operational mode or condition.

A programmable function could be imported at the control [switch].

Time Out Shut-Down 35 One such function could be an automated shut-down after a prescribed interval of non-use. This time-out shut down, would require a manual re-set - either at the control or the actuator itself.

A timer capability would allow temporary overnight or quiescent shut down and reset, for peace of mind.

This time-out facility could be disabled if overnight water consumption devices, such 45 as washing machines on off-peak tariffs, were operational.

Appliance Monitoring The supply lines to appliances could be monitored to disable or enable control of the 50 primary shut-off valve according to appliance consumption.

Appliance [in-line] flow monitoring could be achieved by, say, flow biassed indicators,

or miniature current generators, such as spinner vanes or turbine wheels.

[Simplified] versions of the valve and actuator could be installed at multiple locations to allow flexible, partial shut-down of limited operational zones.

Thus, say, a local pipe burst could be isolated and supply preserved to other appliances. Bypass A bypass line, with a manual bypass valve, could be fitted [in parallel, or as a shunt] across the remote valve, to preserve water supply, in the event of actuator malfunction or electrical supply failure.

15 A mechanical trip wire could run from a manual lever on the actuator to the manual bypass valve - say, to release a spring-loaded latch detent holding the valve closed until released.

That is, the bypass valve would be biassed into a normally closed position.

A manual reset would be required to disable the bypass and re-enable the shut-off valve. The primary shut-off valve actuator admits of a variety of formats.

Balanced Valve Member Thus, for example, a 'flip-flop', or balanced valve member could be held open or shut primarily by water pressure upon one side or other of the valve member.

This would require only modest actuator 'upset' forces to tip the valve, about its balance point, into a flow obstruction, or shut-off mode.

A more substantial force could be contrived for valve member position reset, against 35 mains pressure.

A diaphragm carrying a needle valve member could be configured to achieve this.

Alternatively, a linear or rotary spool valve with ports disposed along the range of valve 40 movement, could be employed.

Aside from mechanical bias, such as a [leaf or coil] spring, a linear or rotary electrical actuator could be used to dictate valve member movement.

45 Water pressure could then simply assist, rather than necessarily being a resistance or obstacle to overcome.

Corrosion Inhibitor or De-scaler 50 In order to preserve valve member freedom of movement, a corrosion inhibitor and/or de-scaler could be fitted.

This might use a low current, magnetic influence or a sacrificial anode, to inhibit electrolytic action on the valve member materials.

Alternatively, or in addition, a lime scale inhibitor, configured as a passive in-line 5 cartridge might be used.

Cycling Timed valve cycling - preferably in periods of no demand - could also be admitted to 10 preserve valve member mobility.

Test A test mode could sense extraordinary high actuator loads attendant valve member 15 movement, and/or inability of the valve member to reach its extremities of movement as an early warning of seizure risk External Drive 20 The valve member could protrude beyond the valve body to allow the option of external drive.

Thus, in the case of a rotary valve member, a spigot could be fitted for coupling to a manual torque bar, or a portable electric drill chuck, or even an impact driver to apply 25 momentary shock loads sufficient to break internal corrosion binding, but not valve member fracture.

In the case of a linear valve member, external continuous [hand] pressure, or sudden impact with a soft faced mallet or the like, could trip valve member movement 30 continued by water pressure.

The primary shut -off valve could be configured as normally open - and closable only on occasion by actuator energisation.

35 No continuous actuator current would then be required.

Alternatively, a normally-closed valve mode could be employed - requiring positive actuator energisation to open, with a default closure upon actuator disabling.

40 The actuator could be coupled to a wireless or opto-electronic (say, infra red) link with a (say, hand-held) remote control switch.

An interface could allow operational integration with an alarm system.

45 That is, alarm set, could automatically disable the water supply.

Alarm systems can be monitored or trigger remotely by telephone lines, area coded broadcast signals, through a computer link - and the water connection added to the alarm remote functionality.

This would represent a precautionary defensive measure against vandalism to which institutions such as schools and colleges are vulnerable.

In a larger system, with multiple mains feeds, individual valves could be installed for each feed, under a common centralised - multi-mode - command module.

5 Flow condition monitors could be used to determine wholesale or selective shut-off and isolation of such multiple mains feeds, as circumstances dictate.

An external temperature monitor and a cross-reference to upstream water flow

temperatures could be used to trigger precautionary shut-off in no flow demand 1 0 conditions.

An automated test reset mode could re-establish supply momentarily and monitor for extraordinary demand - whereupon the system could be shut down overall or locally.

15 A memory could accumulate patterns of usage and trigger shut-down upon extraordinary demand sequences.

A proprietary computer with a bespoke program - coupled by remote cable or radio link to the valve actuator and on board or appliance localised downstream flow monitors 20 could be used to fulfil this pattern accumulation and monitoring function.

A computer modem would open the facility to potential global access over the internet. 25 Thus many institutions could share the cost of a common flow monitoring and control service. Embodiments 30 There now follows a description of some particular embodiments of a water system

with emergency supply isolation and contents drainage provision according to the invention, by way of example only, with reference to the accompanying diagrammatic and schematic drawings, in which [for simplicity and clarity] not every plumbing detail is depicted, but in which: Figure 1 A shows part of the plumbing circuit of a [domestic] water and heating system, in an emergency mains shut-off and system drainage operational mode; Figure 1 B shows the system of Figure 1A in a normal operational mode; Figure 1 C shows a detail of a remote actuated shut-off or isolator valve and attendant controller; Figures 2A through 2C show optional control features; Thus, more specifically: Figure 2A shows an integrated valve, actuator and remote signal receiver, for wireless wave signal, or (infra red) optical beam actuation; Figure 2B shows a remote control switch with a transmitter for sending a command signal to the actuator of Figure 2A; and

Figure 2C shows an emergency 'panic' push-button control switch for the valve actuator of Figure 2A, admitting of either or both a hard wired or ethereal signal link; 5 Figures 3A and 3B show optional appliance demand flow monitors, for integration into the control of the valve actuator of Figures 1 through 2C; Thus, more specifically; 10 Figure 3A shows a branched network of appliances, each with respective demand flow monitors connected to a common control unit dictating function of a [mains] stop valve (not shown); and Figure 3B shows an individual flow monitor unit; Figures 4A and 4B show a facility for external manual operation of a remote powered actuator for an isolator valve; Thus, more specifically; Figure 4A shows a 'sheltered' valve member, or actuator, drive shaft end spigot, accessible externally of the valve and actuator body, using a bespoke [spanner] tool; Figure 4B shows the actuator and valve of Figure 4A with a bespoke [spanner] tool 25 fitted for manual valve member operation; an over-ride coupling could be fitted to avoid injury, should the actuator unexpectedly be enabled while the tool is in place; Figures 5A and 5B show a normally [biassed] closed valve and actuator; 30 Thus, more specifically; Figure 5A shows a valve with valve member biassed on to a valve seat by inlet water pressure and a mechanical [coil] spring fitted externally of the valve chamber, in the actuator; with a supplementary sealing and closure bias diaphragm in the valve 35 chamber; the valve is shown in a closed condition; Figure 5B shows the valve of Figure 5A in an open condition, allowing flow interconnection between inlet and outlet ports; 40 Figures 6A through 6C show an alternative, normally closed, valve construction to that of Figures 5A and 5B, using a 'low-load' actuator and spool bleed or diverter valve member to direct internal flow and so bias a larger 'floating' primary valve member; Thus, more specifically; Figure 6A shows a valve member open; Figure 6B shows the valve member closing; and 50 Figure 6C shows the valve member closed upon its valve seat, isolating inlet and outlet ports in a valve chamber;

Figures 7A through 7C show a three-way combination isolator and drainage flow diverter valve, for use in the plumbing circuit of Figures 1 A and 1 B and the valve module of Figure 1C - as an alternative to the valves of Figures 5A and 5B and 6A through 6C; Thus, more specifically; Figure 7A shows a spool valve member in a mains and drainage isolation mode; 10 Figure 7B shows the valve member of Figure 7A in a mains connection and drainage isolation mode; and Figure 7C shows the valve member of Figures 7A and 7B in a mains isolation and system drainage mode; 1 5 Figures 8A through 8C show an alternative rotary isolator and drainage valve configuration, in corresponding operational modes to those of Figures 7A through 7C respectively; 20 Thus, more specifically; Figure 8A shows a rotary valve member in a mains and drainage isolation mode; Figure 8B shows the rotary valve member of Figure 8A in a mains connection and 25 drainage isolation mode; Figure 8C shows the valve member of Figures 8A and 8B in a mains isolation and system drainage mode; Referring to the drawings, a [domestic] internal water supply system, fed by a rising mains supply 11, is fitted with emergency isolation and drainage facility.

Alow pressure hot water system has a hot water tank 33, gravity fed from a cold water 35 header tank 31, in turn supplied by a mains feed 12.

Mains isolation is by a valve module 10, detailed in Figure 1 C, under the command of a master control unit 20, through a command line 41.

40 Mains isolation deprives the system of a high pressure water supply for those taps or appliances fed directly therefrom.

However, the low pressure hot water system remains enabled - at least until such time as the cold water header tank empties and is not replenished, in the absence of a 45 mains feed.

A failure, such as a pipe or joint rupture, in the cold water side could thus release a not inconsiderable volume of water still in the system.

50 This is the rationale for the drainage facility according to the invention.

Drainage is effected by opening a drain valve 30, again under the command of control

unit 20.

Such drainage is also generally useful in system maintenance and repair.

5 Moreover, drainage can embrace the mains side and empty all pipework and reservoirs. Whilst, in principle, additional drainage paths [ie pipework] could be contrived, in practice the present invention allows existing feed [in normal operation] pipes to be 10 (re-)used, in reverse- flow, for drainage.

Thus, essentially, hot water system drainage is through a drain line 34, drain valve 30, and a return line 36, into what was a feed line 12 in normal operation (see Figure 1 B).

15 Drain valve 30 is itself under a command line 42, from control unit 20.

Return line 36 / 12 is routed through the mains isolator valve 10 to a drain line 37 and external drain 38.

20 An air break 39 allows air ingestion or exhaustion to break any internal air-lock which might otherwise inhibit drainage or indeed system re-fill.

This effectively represents re-deployment of the initial mains feed routing in normal operation. In this way, residual water in the mains line - and indeed all interconnected upstream lines (subject to venting to break any air locks) - would also be drained.

Alternatively, a supplementary dedicated return line (not shown) could be linked via 30 drain valve 30 direct to drainage routes 37, 38 - in that case bypassing the dual role feed line 12.

On the hot water side, cold water header tank 31 feeds hot water tank 33 through a down pipe 32 [coupled to lower tank levels].

Plpe 32 also becomes a drainage path for the header tank 31 and pipe contents, when drain valve 30 is opened, to access the drain / return lines 34, 36.

A downstream hot water feed line 35 from the hot water tank 33 base - and all 40 interconnected upstream lines - are drained simultaneously (subject to venting to break any airlock).

Heating System 45 A similar facility is featured in a separate hot water heating system 50 depicted within a broken boundary line.

Thus, a boiler 52 is supplied by a dedicated cold water header tank 51, also fed from the rising main 11 and so controlled by the isolator valve module 10.

A heater drain valve 40 connects a radiator circulation line 54 with a drain line 57 to a drainage point 58.

Again, an air break 59 is fitted downstream of the drain, to inhibit air lock formation in the pipe system - which might otherwise impede free drainage or indeed re-fill.

5 A power or command line 43 connects the drain valve 40 to the master control unit 20 - which similarly commands the boiler 52, through a command line 44, so that the boiler 52 is disabled upon system drainage.

Figure 1 B shows the system of Figure 1A in normal feed operation, with drainage 1 0 inhibited.

Corresponding parts are allotted the same references and so will not be described again. 15 It will be noted that return line 36 is unused, and so simply fills to mains pressure from the feed line 12.

+++ 20 Referring to Figure 1C, valve module 10 is coupled in line with the rising main 11, using connectors 21, 23.

A corrosion inhibitor 29 is fitted in line with the inlet side.

25 Remote control [switch] unit 20 is connected to the actuator of shutoff or isolator (and drainage) valve 14 by an umbilical cable 19.

Control unit 20 has a manually-operable, bypass actuator lever 22, connected by a trip wire 18 to a detent or latch (not shown) of a springloaded bypass valve 15.

Once the trip wire>18 is pulled, the latch is released and the bypass valve 15 is opened under the mechanical spring bias.

Bypass valve 15 is connected in series with a bypass loop 17, in turn fitted across the 35 valve 14.

The bypass provision enables preservation of valve opening and attendant enabled water supply in the event of power failure.

40 This would otherwise disable the valve actuator and allow the failsafe default [mechanical spring and/or water pressure] bias to close the valve.

A flow monitoring or detector sensor 16 is fitted on the upstream side of the control valve 14 and is coupled to the control unit 20.

The control unit 20 is configured to trip the control valve 14, upon absence of flow detection by the sensor 16, for a prescribed time period.

A [push fit or compression olive] connector 23 upstream of the flow monitor 16 links 50 the shut-off valve 14 to a downstream water system (not shown).

A facie panel of the control unit 20 features an audio visual indicator 27 reflecting shut

off valve 14 condition.

A relay 28 adjacent the shut-off valve 14 determines the connection of an electrical supply thereto appropriate to energise an internal solenoid actuator.

The relay 28 is in turn controlled by relatively low current from the control unit 20.

Figures 2A through 2C, show control valve operational features already outlined in the drawing introduction and are generally self-explanatory.

1 0 Thus a remote actuator transducer 24 receives coded signals from a hand-held remote controller [transmitter] 26.

In addition, an 'intuitive' action [ie push-to-operate] panic button 25 is remote-linked or 15 hard wired to the actuator 24.

Similarly, with Figures 3A and 3B, in relation to individual appliance flow demand monitoring; and manual valve operational back-up of Figures 4A and 4B.

20 +++

The minimum requirements of valve 14 are shut-off, in which case a separate valve (not shown) could be used for drainage.

25 Figures 5A and 5B along with Figures 6A through 6C show single-mode, shut-off valve constructions.

Such valves could be duplicated for the drainage function and fitted in tandem, with appropriate feed and drainage pipe connections.

However, it is convenient to use a more elaborate multi-port valve and multi-position (specifically, 3- way) valve member, to integrate the shutoff and drainage functions.

Figures 7A through 7C and Figures 8A through 8C show examples of this.

Figures 5A and 5B show a normally closed Isolator valve configuration, with a plunger or poppet valve member whose stem 61 is captured by a coil spring 69 within a solenoid actuator 68.

40 A valve head 63 is urged, by [upward as drawn] spring bias on the valve stem 61, into sealing engagement with a complementary profile valve seat 62 in a valve body.

Water pressure in an inlet 64, also pushes the valve head 63 against the valve seat 62. A diaphragm 67 entrains the valve stem 61 and is stretched one way in the closed position and the opposite way in an open position, as depicted respectively in Figures 5A and 5B.

50 Once the solenoid 68 is energised, the valve stem 61 is driven downwards and the valve head freed from the valve seat 62.

Valve opening connects inlet port 64 of a valve chamber 65 to an outlet port 66.

Figures 6A and Reshow a floating valve seal 73 entrained with a diaphragm 77 in a valve chamber 75 between an inlet 74 and an outlet 76.

A [solenoid] actuator 78 controls movement of a spool valve stem member 71 and alignment of a small stem port 82 with a bleed passage 83 in the valve body.

If the bleed is shut-off, as depicted in Figure 6C, the valve chamber 75 above the 1 0 valve seal 73 starts to fill.

The valve seal 73 is progressively displaced on to the valve seat 72 whereupon water pressure in the inlet 74 communicated above the valve seal 73 urges the valve seal 73 and valve seat 72 further into sealing engagement.

1 5 (Re-)opening the bleed passage 83 releases the pressure above the valve seal 73 and allows it to lift from the valve seat 72, in turn opening a bypass 84 to the outlet 76.

This arrangement effectively allows the valve seal 73 to float in the valve chamber 75 and so minimises actuator forces.

In the multi-function - in fact 3-way - [mains] isolator and drainage valve of Figures 7A through 7C, a linear-action, spool valve 91, slideably disposed in an elongate valve body 95, selectively determines interconnection of either a mains port 94 or a drain port 92 to a system port 96.

An actuator 98 at an end of the valve body 95 determines spool valve 91 position.

A bias spring 93 bearing upon the spool valve 91 from an actuator at one end, pre disposes the valve into a default shut-off condition as shown in Figure 7C.

The drawing introduction summarises the operational modes, which are generally self

explanatory with reference to the drawings.

Similarly, the 3-way isolator and drainage valve of Figures 8A through 8Cuses a rotary 35 valve member 101 to determine interconnection of either mains port 1 04 or drain port 102 to a system port 106.: Again, the drawing introduction summarises the operational modes, which are

generally self-explanatory with reference to the drawings.

Component List 10 valve module 11 rising main [feed line] 5 12 downstream supply line 14 shut-off or isolator valve 15 bypass valve 16 flow sensor 17 bypass loop 10 18 trip wire 19 umbilical cable 20 master control unit 21 coupling 15 22 bypass actuator lever 23 coupling 24 valve actuator with receiver 25 panic button switch 26 remote controller 20 27 audio visual indicator 28 relay 29 corrosion inhibitor 30 drain valve 25 31 header tank 32 drain / feed line 33 hot water tank 34 drain path 35 feed path 30 36 drain path 37 drain path 38 drain 39 air break 35 40 drain valve - heating circuit 41 command One - isolator valve 42 command line - hot water drain valve 43 command line - heating circuit drain valve 44 command line boiler 50 hot water heating system 51 header tank - heating system 52 boiler 54 radiator circuit - return path 45 57 drain path 58 drain 59 air break

61 valve stem 62 valve seat 63 valve head 64 inlet port 5 65 valve chamber 66 outlet port 67 diaphragm 68 solenoid actuator 69 spring 71 spool valve stem member 72 valve seat 73 valve seal 74 inlet port 15 75 valve chamber 76 outlet port 77 diaphragm 78 solenoid actuator 20 82 stem port 83 bleed passage 84 bypass 91 spool valve member 25 92 drain port 93 spring 94 mains port 95 valve body 96 system port 30 98 actuator 101 rotary valve member 102 drain port 104 mains port 35 106 system port

Claims (4)

1. Claims

   5 1. A plumbing system incorporating an emergency shut-off or isolator valve, for isolating the system, from both: 1 0 À a remote mains feed; and À a local water header tank; 15 and a [selectively operable] diversion path, for system drainage; [once the mains has been isolated] through a former pathway of the now isolated mains feed.
2. 2. A plumbing system, fitted with 25 a supply isolator valve, integrated with a system drainage valve.
3. 3. An isolator and drainage valve, substantially as hereinbefore described, with reference to, and as shown in, the accompanying drawings.
4. 4. A plumbing system, 40 fitted with an integrated isolator and drainage valve, as claimed in any of the preceding claims.