ARV Engineering H-tec

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    Automatic Air ValvesFor raw and potable water

    For domestic and industrial sewageTechnical information for project planners and technicians

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    Table of contents Page

    1. The purpose of aerating and air release 4

    2. The points of aerating and air release 4

    3. The ways of aerating and air release 5

    3.1 Ways of functioning 53.1.1 Functioning of H-TEC air valve Model 987 (here type 2): 5

    3.1.2 Functioning of H-TEC air valve Model 986: 5

    4. Types of air valves 6

    4.1 AV Model 987 - Air valve (single orifice / double orifice) 6

    4.2 AV Model 986 - Air valve (with cup seal) 6

    4.3 AVS Model 992 and Model 985 Air valve set 7

    4.3.1 Description of AVS Model 992 Description of AVS Model 985 (diaphragm) 7

    4.3.2 Installation above and below ground 7

    4.4 Accessories 8

    4.4.1 Surface box for below ground installation of air valve set Model 992 8

    4.4.2 Drainage element for air valve set Model 992 84.4.3 Manhole cover and ring for air valve set Model 985 8

    4.4.4 Indicator plates for air valve 8

    4.4.5 Flushing and water tapping set (for air valve set Model 992) 8

    5. Rating of valve size 9

    5.1 Rating of valve size 9

    5.2 Rating according to the flow performance diagram 10

    6. Installation 11

    6.1 Design of the connection 11

    6.2 Air valves in plants and manholes 11

    6.3 H-TEC air valve set, the logical further development of the air valve 12

    6.4 Shortening of air valve set Model 992 on site 12

    6.5 AVS - installation in existing manholes 12

    6.6 AVS - installation in ground water 12

    6.7 AVS - installation in flood areas 13

    6.8 AVS for waste water in ground water areas 13

    6.9 AV for water treatment plants 13

    6.10 AV for sterilization plants 13

    6.11 AV upstream and AV downstream of control valves 13

    6.12 AV in fire extinguishing systems 14

    6.13 AV upstream and downstream of reductions 14

    6.14 AV on waste water head pipes with automatic aeration 14

    6.15 AV on waste water vacuum pipes 14

    6.16 Insulation 14

    7. Pressure testing 15

    8. Functional testing and maintenance 15

    8.1 Reasons for maintenance 15

    8.2 Maintenance intervals 15

    8.3 Important maintenance work 15

    8.3.1 Maintenance of air valve set Model 992 16

    8.3.2 Maintenance of AVS Model 985 17

    9. Specification 18

    9.1 Air valves 18

    9.2 Air valve sets 19

    9.3 Air valve with stand pipe base 199.4 Accessories 20

    10. Safety hints 20

    11. References 20

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    2. The points of aerating and air release

    The Air Valve Releases air from the pipeline:accumulations of air must be expected where the operating

    pressure is lower than in neighbouring pipeline sections:

    a) at each geodesic high point

    b) at each hydraulic high point

    c) at long ascending or descending pipe sections (recommended installation in intervals of

    approx. 0.5 mile/800 m)

    d) downstream of pumps and upstream of throttling points

    The Air Valve admits the required amount of air:at each spot of the pipeline where negative pressure must

    be expected, such as:

    e) downstream of quick-acting valves (pipe fracture safety valves PFSV)

    1. The purpose of aerating and air release

    A water transport system is to be kept in an operating condition as stable as possible by taking the appropriate

    measures.

    Inclusions of air may have considerable negative effects on a pipeline system, such as:

    - longer running time pumps - higher energy input, shorter lifecycle of pumps

    - pressure fluctuations

    - reduction of flow

    - water hammer - pipe breakage

    - dry running of pumps

    The possibility of air entering into a pipeline system cannot be eliminated entirely. Already the air dissolved

    in the water proper may turn gaseous under certain pressure and temperature conditions. Even larger quan-

    tities of air will get into the pipeline system during maintenance work. These amounts of air will collect at cer-

    tain points from where they have to be carried off by means of the appropriate valves (see below illustration).

    On the other hand, the lack of air may also lead to failures.Negative pressure will be created when wa-

    ter flows off too fast. This is mostly the case when pipes get drained or when pipe fractures occur, as well as

    in case of pumps being disconnected or downstream of quick-acting valves such as pipe fracture safety val-

    ves, where the flow of water is stopped abruptly, thus creating a negative pressure between the valve and the

    head of water being discharged. In this case sufficient air must be admitted to the pipeline through the air val-

    ve to limit the negative pressure and prevent damage to the pipeline.

    Moreover, there are accumulations of gas in waste water because of processes of decay and because of the

    deliberate blowing in of air.

    This implies the following requirements on air valves:

    - releasing minor amounts of air under operating pressure

    - releasing major amounts of air

    - admitting major amounts of air

    b

    RBS

    e

    a b

    c

    d

    c

    c

    a b

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    3. The ways of aerating and air release

    large cross section

    A =1.488 in2small cross section

    A =0.003 in2

    3.1.2 Functioning of H-TEC air valve Model 986:

    (This valve is also installed in air valve set Model 985)

    Medium: potable water and waste water

    Releasing minor amounts

    of air:

    During operation of a pipe-

    line releasing is effected via

    the small cross section.

    Aerating:

    During draining of

    a pipeline aeration

    is effected via the

    large cross section.

    Closing:

    After venting the

    valve closes auto-

    matically.

    Releasing major amounts

    of air:

    During filling a pipeline re-

    leasing is effected via the

    large cross section.

    Releasing minor amounts

    of air:

    During operation of a pipe-line the venting cross sec-

    tion will be opened as far

    as necessary.

    Aerating:

    During draining of a

    pipeline aeration iseffected via the who-

    le aeration cross sec-

    tion.

    Closing:

    After venting the val-

    ve closes automati-cally.

    Releasing major amounts

    of air:

    For filling a pipeline thewhole venting cross

    section is available.

    3.1.1 Functioning of H-TEC air valve Model 987 (here type 2):

    Medium: potable water

    3.1 Ways of functioning

    A =0.744 in2 A =0 ..... 0.744 in2

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    Improved air intake and release capacity

    Very high air release during operation

    continuously variable from 0 to 250 psi / 16 bar

    High-grade materials

    Easy maintenance

    Excellent UV resistance

    Only for air release or air intake - on request

    350 psi / PN 25 - on request

    HaVent, the new performance generation

    Air release capacity during pipeline filling

    The air release capacity is 106.000 gal/h even at a dif-

    ferential pressure of 1.45 psi / 0,1 bar

    Air release during operation

    The air release capacity over 26.500 gal/h even at a

    differential pressure of 29 psi / 2 bar

    Aeration of pipeline

    The air intake capacity is approx. 79.500 gal/h at a

    negative pressure of -1.45 psi / -0,1 bar

    Possible connections

    Female thread 2

    Male thread 2

    Flange 4

    Flange other nominal width on request!

    AirreleasecapacityQ(

    m3/h)

    Differential pressure (bar) Differential pressure (bar)

    Negative pressure (bar)

    AirreleasecapacityQ(

    m3/h)

    Airintakecapacity(m3/h)

    Venti lation on highest level for water pipelines

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    Large outlet cross section for maximum air release

    and intake capacity during pipeline filling or draining

    A = 2.3 in2

    Large air release cross section for reliable air release

    during operation

    Amax. = 0.3 in2

    High-grade enclosure of aluminium

    Robust float of foamed plastics

    Flow control for optimized closing

    Valve mechanism

    No loose components

    Can be taken out in one piece

    Easy cleaning

    Easy exchange of wear parts

    if required

    Technical features

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    NPT 2: for large amounts of air NPT 1: for small amounts of air

    4.1 Model 987 - Air Valve (single orifice / double orifice)

    Materials:

    Body POM

    Seat CuZn35Pb3As

    Float POM

    Valve gasket EPDM

    UV cap PE

    Insect protective grid ss316

    Technical data: NP 2 NP 1

    Test pressure (body) body 350 psi / 24 bar body 350 psi / 24 bar

    Operating pressure standard: 14.5-250 psi / 0,8 - 17.2 bar standard: 11.6 - 250 psi

    alternative: 1.5 - 87 psi alternative: 1.5 - 87 psi

    Opening cross section 1.448 in2 / 0.003 in2 0.003 in2

    Max. air release capacity 50.190 gal/h 2.377 gal/h

    Connection female thread 2 or flange female thread 1

    Insect protective grid yes no

    Weight 5.1 lbs / 2,35 kg 1.65 lbs / 0.75 kg

    4.2 Model 986 - Air Valve (with cup seal)

    Materials:

    Body fluidized bed epoxy

    powder coated

    alternatively SS 316

    Body nut with screen POM / 1.4301

    Float POM

    Valve body - bonnet POM

    O-ring 160 x 6 NBROutlet elbow with strainer PE 100 / SS 316

    Technical data:

    Test pressure (body) body 350 psi / 24 bar

    Operating range 0 -250 psi/ 0 16 bar

    Opening cross section 0.75 in2/ 480 mm2

    Max. air release capacity 230 m3/h / 60.760 gal/h

    Connection female thread 2 or Flange 2 - 8

    other flanges on request

    Media raw and potable water

    domestic and industrial waste water

    Large amounts of air

    can be released under

    operating pressure

    due to infinitely

    variable operation!

    4. Types of Air Valves

    Features:

    infinitely variable

    operation from 0 bar onward

    seat not in contact with the medium

    suitable for parallel operation

    large orifice

    = prevents contamination

    = high air release capacity even under

    operating pressure

    On request: valve with ventilate-function only

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    4.3.1 Description of Air Valve Set, Model 992

    Medium: potable water

    stand pipe of stainless steel replaces

    the chamber and permits easy main-

    tenance of the air valve

    H-TEC 2 air valve

    high-grade materials such as POM

    for the body, bronze for the seats and

    EPDM for sealings ensure corrosion

    resistance and permanent function

    (maintenance see item 6.)

    drain-off fitting

    hood with air vent slots

    automatic shut-off function via initial

    spring tension ensures sealing even

    at 0 psi

    insect protective grid

    additional elongated holes permit

    shortening by 100 mm

    Description of Air Valve Set Model 985 (diaphragm)

    Medium: potable water and waste water

    Above ground

    (PCD)

    2.5 ft / 0,75 m

    3.3 ft / 1,00 m

    4.1 ft / 1,25 m

    4.9 ft / 1,50 m

    L

    Spigot end

    2.7 ft / 815 mm

    3.7 ft / 1115 mm

    4.5 ft / 1365 mm

    5.3 ft / 1615 mm

    L

    Flange

    2.5 ft / 755 mm

    3,5 ft / 1055 mm

    4.3 ft / 1305 mm

    5.1 ft / 1555 mm

    Below ground

    (PCD)

    3.3 ft / 1,00 m

    4.1 ft / 1,25 m

    4.9 ft / 1,50 m

    5.7 ft / 1,75 m

    Pipe cover depth:

    4.3.2 Installation above and below ground

    An Air Valve Set can be installed both above ground

    and below ground. The above ground type will be used

    wherever the valve shall be installed in open terrain.

    above ground below ground

    air valve

    cover

    chamber cylinder

    operating rod

    shut-off facility with blank

    of stainless steel

    BAIOspigot end 3 or

    ange 3

    drain-off fitting (optional:

    can be

    closed via end fitting)

    Both Air Valve Sets are available with ange 3 or BAIOspigot end. When using a BAIOspigot end please apply a dirt cover andlocking ring (see specification of accessories).

    4.3 Model 992 and Model 985 Air Valve Set

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    Diagram 1: Filling the pipeline

    200

    insidediameterdi

    ofpipelinedi[mm]

    100 300 400 600 900 2000

    100

    200

    300

    400

    50042 6 10 14 18 40

    required venting cross section A [ mm 2]

    max. adm. flow in the pipeline Q [ l / s ]

    Diagram 2: Draining the pipeline

    Example of rating an Air Valve:

    For a pipeline with an inside diameter of di= 12 the required size of the Air Valve shall be determined.

    Filling the pipeline:

    According to diagram 1 the free flow cross section in the air valve of a pipeline of di= 12 must be

    at least 0.14 sq.inch. The flow in the pipeline must not exceed 4.8 gal/s.

    Draining the pipeline:

    According to diagram 2 the max. admissible flow on drainage of the pipeline is 11 gal/s at a free flow cross

    section in the valve of 0.14 sq.inch.

    This means that the H-TEC Air Valve Model 987 2 (A = 960 mm 2) is able to manage the accumulating amount

    of air for aerating and/or draining of a pipeline do 12 under the specied assumptions.

    Since the above calculation may not be perfectly adapted to any pipe pressure situation possibly prevailing we

    recommend a comprehensive hydraulic calculation*. If, during filling of a pipelines, even larger amounts of air

    5. Rating of valve size

    5.1 Rating of valve size

    In general, there are no limits to the pipeline diameter for operational air release. However, the accumulating

    amounts of air of a pipeline must be considered. They must not exceed the values specified in the flow diagram.

    As regards the required valve sizes and/or the free flow cross sections thereof the diagrams and cal-

    culations are based on the following assumptions:

    a) Release during filling of a pipeline:

    - The maximum water hammer during closing of the Air Valve is limited to 44psi/3 bar (which is equivalent

    to a max. flow rate of 10 inch/s in the pipeline)

    - The propagation rate of the pressure surges in the pipeline is assumed to be a = 4000 ft/s

    - The maximum flow rate in the free flow cross section of the Air Valve is limited to VE= 65 ft/s, since an exces-

    sive flow rate of the air might tear along the float of the Air Valve, thus closing the valve before the venting

    process proper.

    b) Aeration during drainage of a pipeline:

    - The absolute pressure in the pipeline is limited: pR= 13.8 psi/0,95 bar (= negative pressure of 0.7 psi 0,05 bar)

    - The contraction and friction value of the Air Valve is: = 0,52

    10

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    5.2 Rating according to the flow performance diagram

    The following diagram shows the interrelation between air release and aeration capacity of the valve at a given

    overpressure / negative pressure in the valve.

    Explanation by way of examples:

    a) Air release capacity of AV 1 at 73 psi /

    5 bar: 1.590 gal/h

    b) Air release capacity of AV 987 2 at

    0.7 psi / 0,05 bar: 47.500 gal/h

    c) Air release capacity of AV 987 2 at 73 psi / 5 bar:

    2.000 gal/h (as the big orifice is closed because of the air

    flow)d) Air intake capacity of AV 987 2: 145.300 gal/h

    must be expected, air release may also be performed manually. In this case a flushing and water tapping set is

    installed in the H-TEC Air Valve Set. However, other air release devices such as hydrants, may be used, too.

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    6. Installation

    The points of installation are usually the relative or absolute high points of the pipeline. Because of the regular

    checks that are necessary they shall be easily accessible and not be situated in highly frequented traffic areas. Ho-

    wever, the correct place of installation is more important (e.g. high point).

    6.1 Design of the connection

    The nominal width of the supply line shall be as large as possible and should be equivalent to at least the val-

    ve size. This pipeline should run vertical from the pipeline to the valve. The dimension of the upstream shut-off

    valve, too, should be equivalent to at least the valve size. The largely dimensioned supply line to the valve ser-

    ves the purpose of collecting the air carried along with the water from the main line at this point to be then

    discharged by the valve.

    For pipelines < 24 a sufciently dimensioned

    ventilation chamber is required. Unless determined

    more precisely the ventilation chamber can be regar-

    ded as sufficiently dimensioned if its constructional

    height is equivalent to the diameter of the pipeline

    and its cross section is approximately half the crosssection of the pipeline.

    Moreover, a central shut-off facility, a tee with air re-

    lease and air intake facility and a lateral outlet for

    manual air intake and release as well as for depressu-

    rization before working at the air valve are required.

    The shut-off valve permits the installation and dis-

    mantling of the air release and intake facility as well

    as the manual air release facility without interruption

    of operation. Functional testing of the air intake and

    release facility and/or the floats and the manual air

    release facility with closed shut-off valve are possi-

    ble. This shut-off valve must remain closed duringpressure testing (see page 15).

    Warning:Prior to installation of an Air Valve the pipeline must be flushed, since dirt and drilling chips might affecttightness (see also flushing and water tapping set).

    air valve

    manual air release facilityshut-off facility

    2

    3

    1

    2

    3

    Air Valves are installed in rooms or manholes. Inside

    the buildings care must be taken that the opening is

    sufficiently large to ensure an unobstructed flowing

    in and out of the air. By means of the integrated fine

    screen vermin and dirt are prevented from getting into

    the valve. As regards the design of the building care

    shall be taken that the residual water carried along

    in the process of air release can be discharged via a

    drainage device (drainage element).

    6.2 Air Valves in plants and manholes

    Warning:

    Prior to entering manholes make sure that suf-

    cient fresh air is admitted!

    1

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    Conventional manhole H-TEC Air Valve Set

    6.3 H-TEC Air Valve Set, the logical further development of the air valve

    Advantages of H-TEC air valve set:

    low costs no access of manhole required integrated shut-off element maintenance work easy and time-saving

    No danger because of access to manhole!

    6.4 Shortening of Air Valve Set Model. 992 on site

    Both the above ground and the below ground version

    of the Air Valve Set may require shortening on site be-cause of unexpected changes of the pipe cover depth.

    According to the drawing the operating tube (with the

    marking) and the stand pipe of stainless steel are cut

    by 4. Make sure to produce a straight cut edge.

    6.5 Installation in existing manholes

    Air Valve Sets can also be installed in existing manholes. They are mounted on the pipeline instead of the old air

    valve. The manhole is backfilled with bulk material, thus avoiding future maintenance of the manhole. Moreover,the valve can be installed and dismantled from above for testing and maintenance.

    bulk

    material

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    6.6 Installation in ground water

    If rising ground water exceeds the level of the drain-

    off fitting dirty water may be sucked into the pipeline

    during aeration. The drain-off fitting must be closed or

    a back flow preventer must be installed. (This is notincluded in the standard scope of supply and must

    be ordered separately). In both cases it must be en-

    sured by regular inspection of the Air Valve Set that

    no groundor rain water can accumulate in the

    Air Valve Set. If required,the water must be pumped

    out by means of a handpump.

    Warning:Penetrating ground or rain water may be

    sucked into the pipeline in case of negative pressure.

    Contamination and germs may be carried in.

    6.7 Installation in flood areas

    In flood areas the length of the AVS shall be rated such

    that the hood with the air vent slots is approx 1.5 ft

    above the water level to be expected to prevent any

    dirty water from penetrating the Air Valve Set. The drain-off fitting must be closed. (This is not in-

    cluded in the standard scope of supply and must

    be prepared on site).

    Warning: Penetrating ground or rain water may be

    sucked into the pipeline in case of negative pressure.

    Contamination and germs may be carried in.

    6.8 For waste water in ground water areas

    The drain-off fitting must be closed, e.g. by means of

    a pipe and end fitting, to prevent waste water from

    emerging into the soil.

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    6.9 For water treatment plants

    Automatic air release at the surge tank after water

    treatment with compressed air.

    For dimensioning, please consider the maximum air

    release amount at the given operating pressure of theAir Valve (see diagram).

    Because of its high air release capacity under opera-

    ting pressure the valve Model 986 is best suited for

    this application.

    surge tank

    compressed air

    from compressor

    6.10 For sterilization plants

    In water sterilization plants the water is exposed to UV

    light. In this process air is set free that must be

    released at the highest point of the radiation plant.radiation

    cylinder

    6.11 Upstream and Air Valve downstream of control-

    valves

    Control valves are very sensitive to airlocks in water.

    Therefore, depending on the operational conditions, itmay be necessary to install an air release valve

    upstream of the control valve to ensure smooth

    operation.

    In this case a mere air release valveis re-

    commended that is created by installing a

    nonreturn valve into the output pipe of the Air Valve

    (please order separa-tely).

    Warning: This nonreturn valve will reduce air re-

    lease capacity!

    As at all throttle points in the pipeline system, air is set free downstream of control valves. Ideally, this air shall

    be removed from the pipeline while still in the manhole or building where the control valve is installed.

    Especially downstream of pipe fracture safety valves an aeration facility must be installed to prevent negative

    pressure as well as consequential damage to the pipelines caused by such negative pressure.

    6.12 In fire extinguishing systems

    In fire extinguishing systems pumps are used that en-

    sure sufficient delivery in case of emergency. These

    pumps will drag air into the pipeline that has to be re-

    moved again at the nearest high point.

    Before installation, please observe the applicable

    national regulations.

    ARV

    ARV

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    6.13 Upstream and downstream of reductions

    a) Upstream of reductions in the pipeline system, i.e.

    upstream of major contractions, air will accumulate

    that is not carried on (see curves for self-venting

    of pipelines. The Air Valve releases the

    accumulated air automatically.

    b) In case of flow from the smaller to the larger

    pipeline, too, venting may be necessary, e.g. for a

    descending pipeline, if the rate for self-venting is

    not reached.

    6.14 On waste water head pipes with automatic aeration

    In some situations it is necessary to blow air into the pressure line via a compressor or pressure tank at regular

    intervals, in addition to normal pumping.

    In these cases we recommend the use of an air release stop, which is mounted at delivery (also possible later

    when already installed) on the valve outlet elbow. During normal pumping the air

    release stop is out of action. If, however, very high air quantities are supplied to the

    pressure line via a compressor or pressure tank,then the air release stop responds

    mechanically and closes the valve. After scavenging (air), the valve goes back to its

    normal operating state.

    For more detailed information please contact our applications engineering department.

    6.15 On waste water vacuum pipes

    In waste water vacuum pipes only air release valves may be used. To this end a nonreturn valve shall be in

    stalled at the valve outlet side.

    Warning: This nonreturn valve will reduce air release capacity!

    6.16 Insulation

    Valves installed directly on the main line are not very susceptible to freezing, since the water in the valve is

    heated by the water owing in the main line. However, in case that an offset installation is necessary, i.e. in

    case of installation beside the main line, there is the danger of freezing.

    In this case both the supply line to the valve and the valve proper must be insulated. The valve in the Air Valve Set

    is protected from frost by inserting a disk cut to size and consisting of insulating material of approx. 2 in

    thickness with a hole in the centre (see drawing) is inserted halfway up the stand pipe. This disk must

    not seal tightly to ensure that air release and intake are not inhibited (approx. 10 holes with a diameter of 0.4 inch).

    The Air Valve in the manhole is protected from frost by lining the manhole walls and the manhole cover with insu-

    lating material (see drawing b).

    In case of waste water valves, too, insulation may be sensible. Though there is usually no danger of freezing, the

    depositing of grease at the wall of the Air Valve will be increased by temperature differences.

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    Drawing a Drawing b

    Air Valves installed in the open, for example below bridges, must also be insulated to be frost-resistant. In

    this case, insulation may be effected, for example, by backfilling the surface box with polystyrene chips. To

    discharge splash water a drainage pipe leading from the Air Valve into the open must be installed.

    insulation

    approx. 10 mminsulation

    7. Pressure testing

    Prior to delivery H-TEC air valves are tested, including functional testing at max. operating

    pressure and body testing at 1,5 times the operating pressure.

    Prior to pressure testing of pipelines with Air Valve Set and/or Air Valve Sets the shut-off device must be clo-

    sed, otherwise the pipeline may be vented during the pressure test, rendering the result of the

    pressure test useless.

    AV: Close shut-off device upstream of the valve.

    AVS 992: Take Air Valve out of the Air Valve Set the integrated shut-off device of the set closes

    automatically.

    AVS 985: Close shut-off device by means of half turn.

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    8. Functional testing and maintenance

    b c

    a

    Open surface box

    Loosen screw a

    Take off hood

    Loosen screw b

    Take out spindle

    support c

    Maintenance of Air Valve 2:

    - Clean body and seats

    - Blow out valve bore by means of compressed air

    (see also sectional view item 3.1.1)

    Maintenance of Air Valve 1:

    - Screw out seat and blow through

    - Clean valve seal

    (see also sectional view item 3.1.1)

    On start-up of the valve once again (perform above steps in reverse order) venting must be clearly audible (loud

    hiss) during screwing in of the spindle support. Otherwise the procedure has to be repeated.

    Pull out valve by means

    of operating tube

    Simultaneously the foot

    valve closes the system

    at the bottom

    0

    30

    1545

    8.1 Reasons for maintenance

    Almost all potable waters and waste waters carry along suspended particles and tend to sedimentation. In

    waste water there are also grease deposits and larger foreign bodies accumulating in the Air Valve. To avoidmalfunctions caused by dirt Air Valves must be checked and maintained, if necessary, at regular intervals.

    8.2 Maintenance intervals

    H-TEC recommends regular checks of Air Valves for potable water are demanded at least every 12 months.

    The exact maintenance interval depends on the quality of the water. The first maintenance will be done after

    3 to 6 months after start-up and serves as a first reference value for further testing intervals.

    In case of waste water the maintenance intervals must be adapted to the conditions of the pipeline. Usually,

    the first Air Valves of a series of several valves are contaminated most heavily. There are no generally applica-

    ble rules for maintenance intervals.

    8.3 Important maintenance work This information leaflet can show only the most important steps of maintenance. Please follow our maintenan-

    ce instructions and comply with the safety hints.

    Prior to working at air valves the valve must be shut off via gate valve and unpressurized via an appropriate

    valve. Air valves represent one of the few automatic connections between the pipeline system and the ambien-

    ce. Therefore, they have to be checked at regular intervals. (see also [2]).

    8.3.1 Maintenance of Air Valve Set Model 992

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    8.3.2 Maintenance of Air Valve Set Model 985

    All maintenance and service work can be done from the road surface, thus avoiding the dangers involved with

    entering manholes.

    The Air Valve can be flushed without being dismantled via the two flushing ports (5a / 5b). To this end hoses must

    be connected to the two flushing ports (5a / 5b) in such a way that the inside pressure is released safely afteropening the ball valves (4 / 6). Flushing is performed by passing water from 5a to 5b, possibly adding some clea-

    ning agent.

    4. Put the valve (7) onto the bayonet coupling from abo-

    ve and lock it clockwise. Put the 3/2-way ball valve (6)

    back in place and tighten the screwed unions

    manually until the connections are tight. Put on the

    operating tube (3). Close the ball valve of the lower

    flushing orifice (4). Slowly open the shut-off valve (12)

    below the air valve (counterclockwise). After opening

    offset the operating tube again by 180 (safety func-

    tion against automatic unlocking of the Air Valve).

    Visual inspection of all connections and flushing ori-

    fices.

    If there are any foreign bodies in the valve that cannot be flushed out via the bottom flushing orifice, the valve

    should be dismantled, opened, and the foreign body be removed. To this end proceed as follows:

    1. Take off the cover (1) from the chamber cylinder (2).

    Close the shut-off valve by means of the offset opera-

    ting tube (3) by a half turn (clockwise). The operating

    tube must be offset by 180 before!

    Warning: Even after closing the shut-off valve the

    air valve is pressurized,therefore open the ball val-ve (4) on the lateral flushing pipe carefully and only

    after mounting a hose at the flushing port provided for

    this purpose (5b). Discharge any emerging waste wa-

    ter safely. Dismantle the 3/2-way ball valve (6). To this

    end loosen the screwed union.

    2. Pull the operating tube (3) upward and out of the air

    valve set. Turn the valve (7) counterclockwise until the

    bayonet coupling (8) is loosened. Pull the valve up-

    ward and out of the chamber cylinder (2) at the two

    eye bolts (9) by means of a suitable lifting tool. Anyresidual water is discharged via the drainage device.

    If this is not desired, install an end fitting (13) and

    pump out the chamber.

    3. Open the body screws (10). Clean the valve inside

    (use a cleaning solution, if required, in case of persi-

    stent dirt, let the agent work itself in for a while, befo-

    re cleaning by means of a brush). Screw the valve

    bonnet (11) back on again, making sure that the toro-

    idal sealing ring is fitting properly. Prior to installationof the Air Valve clean all sealing surfaces.

    13

    8

    12

    9

    2

    3

    5b

    6

    1

    11

    10

    4

    5a

    7

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    9. Specification

    9.1 Air Valves

    Air Valves Model 987

    Specification: Air Valve For Water Service ( #987; 1 )

    The valve shall be a combination air/vacuum single

    orifice automatic air release valve with 1 connection

    to the pipeline. The valve shall be of corrosion free

    materials, single orifice for allow air to escape and

    enter in the event of a vacuum condition. The valve

    shall be of one piece body design. Body and float

    shall be Delrin (Polyoximethylene, POM). The seat

    and valve plug made of CuAl10. The valve sealing is

    rubber made of EPDM. The valve shall have a pro-

    tection cap of PE.

    Air and vacuum valves shall be manufactured by Hawle

    Specification: Air Valve For Water Service ( #987; 2 )

    The valve shall be a combination air/vacuum double

    orifice automatic air release valve with 2 connection

    to the pipeline. The valve shall be of one piece body

    design. The internal parts shall have a small orifice

    within tripod for small air discharge and a big orifice

    within bonnet of base housing for main air discharge

    and allow air to enter in the event of a vacuum con-

    dition. The material of the body and the flow shall be

    Delrin ( Polyoximethylene, POM ). The valve sealing

    is rubber made of EPDM. The valve shall have a pro-

    tection cap of PE.Air and vacuum valves shall be manufactured by Hawle

    Air Valve for Sewage ans Water Service 986

    Specification:

    Combination Air Valves shall conform to the follow-

    ing:Automatic Air and Vacuum Valves shall be infinitely

    variable automatic air and vacuum valves designed

    to allow escape of air for a operating range starting

    from pressure range: 0,0 through 250 psi ( 0 17,2

    bar ), close watertight when liquid enters the valve

    even when the fluid is rising without pressure ( no

    minimum operating pressure required), allow air to

    enter in the event of a vacuum, and soft working be-

    havior as water hammer inhibition realized by roll-on

    diaphragm and spring mechanism. When the sealing

    device of the valve is closed an air cushion is trapped

    between the fluid and sealing area, a mud deflec-

    tor made of PE allows no contact between fluid and

    sealing area. The valve body and spindle spring shall

    be stainless steel grade 316Ti, designed to facilitate

    disassembly for cleaning and maintenance. The float

    shall be Delrin ( Polyoximethylene, POM ); the valve

    seat and all working parts shall be of corrosion resi-

    stant materials. Valves shall be equipped with the ne-

    cessary attachments, including ball valve, to permit

    back flushing after installation without dismantling

    the valve. Valves shall be recommended by the ma-

    nufacturer for wastewater service.Air and vacuum valves shall be manufactured by Hawle.

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    Automatic air valve with standpipe of stainless steel(replacing a shaft), BAIO spigot end or anged con-

    nection drilled, of Ductile Iron (GJS-400), high-quality

    corrosion protection by fluidized bed epoxy powder

    coating inside and outside. The valve shall be a com-

    bination air/vacuum double orifice automatic air

    release valve. The valve shall be of one piece body

    design. The internal parts shall have a small orifice

    within tripod for small air discharge and a big orifice

    within bonnet of base housing for main air discharge

    and allow air to enter in the event of a vacuum con-

    dition. The material of the body and the flow shall beDelrin ( Polyoximethylene, POM ). The valve sealing

    is rubber made of EPDM. Standpipe of stainless steel

    suitable for above ground and underground installati-

    on, standpipe with drain-off fitting.

    Air and vacuum valves shall be manufactured by

    Hawle.

    9.2 Air Valve sets

    Automatic Air Valve Set ( #992 ) Valve with Shaft for

    Underground Installation

    Automatic Air and Vacuum Valves shall be infinitelyvariable automatic air and vacuum valves designed

    to allow escape of air for a operating range starting

    from pressure range: 0,0 through 250 psi ( 0 17,2

    bar ), close watertight when liquid enters the valve

    even when the fluid is rising without pressure ( no

    minimum operating pressure required), allow air to

    enter in the event of a vacuum, and soft working

    behaviour as water hammer inhibition realized by

    roll-on diaphragm and spring mechanism. When the

    sealing device of the valve is closed an air cushion is

    trapped between the fluid and sealing area, a muddeflector made of PE allows no contact between fluid

    and sealing area. The valve body and spindle spring

    shall be stainless steel grade 316Ti, designed to fa-

    cilitate disassembly for cleaning and maintenance.

    The oat shall be Delrin ( Polyoximethylene, POM );

    the valve seat and all working parts shall be of cor-

    rosion resistant materials. Valves shall be equipped

    with the necessary attachments, including ball valve,

    to permit back flushing after installation without dis-

    mantling the valve. Valves shall be recommended by

    the manufacturer for wastewater service.

    The air valve set is provided with a PE shaft repla-

    cing a manhole, a shut-off device with a steel plate

    of hard-rolled stainless steel and straight-through

    bore when open, two maintenance outlets with hose

    connection and ball valve, lateral outlet for waste air

    with PE elbow as swivelling device equipped with

    additional protection grid, drain-off fitting at the shaft

    bottom. After closing the shut-off device by integra-

    ted operating tool and removal of the upper ball valve

    the air valve can be taken out of the shaft for main-

    tenance purposes. Valves shall be recommended bythe manufacturer for wastewater service.

    Air and vacuum valves shall be manufactured by

    Hawle

    Air Valve Set for Operating Range 0 250 psi /

    0 17,2 bar ( #985 )

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    Component 80 Material

    1 Spigot end 80 GGG 40, fluidized bed epoxy powder coated

    2 Shut-off faci lity GGG 40, fluidized bed epoxy powder coated

    3 Air Valve steel, St. 37 fluidized bed epoxy powder coated

    4 Chamber cylinder PE

    5 Cover PE

    6 Three-way ball valve PVC

    7 Hose coupling PA 6 GF 25

    8 Ball valve stainless steel

    9 Operating rod square steel St. 37 fluidized bed epoxy powder coated

    10 Bottom plate sheet steel St. 37 fluidized bed epoxy powder coated

    11 Drain-off fitting GGG 40, fluidized bed epoxy powder coated

    Accessories

    12 End fitting(please observe surcharge!) POM

    13 Manhole cover GGG 40, bituminized

    Manhole ring GG 24, bituminized

    Drawing representing Air Valve Set with BAIOspigot end 3

    Air Valve Set Model 985 with spigot end

    Air Valve Set Model 985 with flange

    Air Valve Set Model 985 with PE tailMedium: raw and potable water, domestic and industrial waste water

    Operating range: 0 16 bar

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    Automatic Air Valve Set Model 992 with spigot end

    Automatic Air Valve Set Model 992 with flange

    Automatic Air Valve Set Model 992 with PE tailMedium: potable water

    Operating pressure: 14.5 - 250 PSI (0,1 6 bar) and 1.5 - 87 PSI (0,1 - 6 bar)

    Component Material

    1.1 Inlet flange GGG 40

    1.2.1 Fitting GGG 40

    1.2.2 O-ring NBR

    1.2.3 Grip ring POM

    1.3 O-ring NBR

    1.4 Sealing flange Rg 7

    1.5 Foot valve POM

    1.6 Spring case MS 58

    1.7 Pressure spring stainless steel

    1.8 Hexagon screw M 10 x 35 DIN 933 stainless steel

    2.1 Bonnet POM

    2.2 O-ring NBR

    2.3 Seat CuZn35Pb3As / EPDM

    2.3.1 Hexagon screw stainless steel

    2.4 Locking plate stainless steel

    2.5 Locknut MS 58

    2.6.1 Bottom part of body POM

    2.6.2 Air valve support POM

    2.7.1 Float bottom part POM

    2.7.2 Ballast EPDM

    2.7.3 Float top part POM / EPDM

    2.7.4 Sealing screw stainless steel

    2.7.5 Fan type lock washer stainless steel

    2.8.1 Sealing cover POM

    2.8.2 Seat for sealing cover EPDM

    2.8.3 O-ring NBR

    2.9 O-ring NBR

    2.10 Hexagon nut stainless steel

    2.11 Washer stainless steel

    2.12 Hexagon socket bolt stainless steel

    2.13 O-ring NBR

    2.14 Insect protective grid stainless steel

    3 Operating tube stainless steel

    4 Centring cap GGG 400

    4.1 Hexagon screw M 8 x 10 DIN 931 stainless steel

    5 Stand pipe stainless steel

    6 Lock ring GGG 40

    7 Hexagon bolt M 16 x 50 DIN 931 stainless steel

    8 Hexagon nut M 16 DIN 934 stainless steel

    9 Washer stainless steel

    10 Sealing EPDM

    11 Cover EPDM

    12 Spindle support GGG 40

    13 Operating screw Ms 58

    14 Hood PE

    15 Hexagon screw M 8 x 60 DIN 931 stainless steel

    16 Washer stainless steel

    17 Drain pipe PE

    The following abbreviations are used:

    AV = air valve

    AVS = air valve set

    ARV = air release valve

    17

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    Edition September 2009- Subject to change