DFG300 Automatic or Manual Actuated Boiler Blowdown Valves

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DFG300 Automatic or Manual Actuated Boiler Blowdown Valves | Manualzz

4057450/4

DFG300

Automatic or Manual Actuated

Boiler Blowdown Valves

Installation and Maintenance Instructions

IM-P405-38

AB Issue 4

DFG300A

DFG300AX

1. Safety information

2. General

product information

3. Installation

4. Operation

5. Maintenance

6. Spare parts

DFG300M

DFG300MX

2

IM-P405-38 AB Issue 4

1. Safety information

Safe operation of these products can only be guaranteed if they are properly installed, commissioned, used and maintained by qualified personnel (see Section 1.11) in compliance with the operating instructions. General installation and safety instructions for pipeline and plant construction, as well as the proper use of tools and safety equipment must also be complied with.

1.1 Intended use

Referring to the Installation and Maintenance Instructions, name-plate and Technical

Information Sheet, check that the product is suitable for the intended use/application.

The products listed below comply with the requirements of the European Pressure

Equipment Directive 97 / 23 / EC and carry the mark when so required. It should be noted that products rated as 'SEP' are required by the Directive not to carry the mark.

The products fall within the following European Pressure Equipment Directive categories:

DFG300A

Product

DN25 and DN32

DN40 and DN50

Group 1 Group 2 Group 1 Group 2

Gases Gases Liquids Liquids

2 SEP SEP SEP

2

2

1

SEP

SEP

SEP

SEP

SEP DFG300AX

DFG300M

DN25

DN25 and DN32

DN40 and DN50

DN25

2

2

2

SEP

1

SEP

SEP

SEP

SEP

SEP

SEP

SEP DFG300MX i) The DFG300A and DFG300M have been specifically designed for use on air, water/ condensate, diathermic oil and /or other fluids which are in Group 2 of the European

Pressure Equipment Directive.

The products’ use on other fluids which are in Group 1 and 2 may be possible but, if this is contemplated, Spirax Sarco should be contacted to confirm the suitability of the product for the application being considered and the request must be stated at the time of order placement.

ii) Check material suitability, pressure and temperature and their maximum and minimum values. If the maximum operating limits of the product are lower than those of the system in which it is being fitted, or if malfunction of the product could result in a dangerous overpressure or overtemperature occurrence, ensure a safety device is included in the system to prevent such over-limit situations.

iii) Determine the correct installation situation and direction of fluid flow. iv) Spirax Sarco products are not intended to withstand external stresses that may be induced by any system to which they are fitted. It is the responsibility of the installer to consider these stresses and take adequate precautions to minimise them.

v) Remove protection covers from all connections and protective film from all name-plates, where appropriate, before installation on steam or other high temperature applications.

IM-P405-38 AB Issue 4

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1.2 Access

Ensure safe access and if necessary a safe working platform (suitably guarded) before attempting to work on the product. Arrange suitable lifting gear if required.

1.3 Lighting

Ensure adequate lighting, particularly where detailed or intricate work is required.

1.4 Hazardous liquids or gases in the pipeline

Consider what is in the pipeline or what may have been in the pipeline at some previous time. Consider: flammable materials, substances hazardous to health, extremes of temperature.

1.5 Hazardous environment around the product

Consider: explosion risk areas, lack of oxygen (e.g. tanks, pits), dangerous gases, extremes of temperature, hot surfaces, fire hazard (e.g. during welding), excessive noise, moving machinery.

1.6 The system

Consider the effect on the complete system of the work proposed. Will any proposed action (e.g. closing isolation valves, electrical isolation) put any other part of the system or any personnel at risk?

Dangers might include isolation of vents or protective devices or the rendering ineffective of controls or alarms. Ensure isolation valves are turned on and off in a gradual way to avoid system shocks.

1.7 Pressure systems

Ensure that any pressure is isolated and safely vented to atmospheric pressure.

Consider double isolation (double block and bleed) and the locking or labelling of closed valves. Do not assume that the system has depressurised even when the pressure gauge indicates zero.

1.8 Temperature

Allow time for temperature to normalise after isolation to avoid danger of burns.

1.9 Tools and consumables

Before starting work ensure that you have suitable tools and /or consumables available. Use only genuine Spirax Sarco replacement parts.

1.10 Protective clothing

Consider whether you and / or others in the vicinity require any protective clothing to protect against the hazards of, for example, chemicals, high / low temperature, radiation, noise, falling objects, and dangers to eyes and face.

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IM-P405-38 AB Issue 4

1.11 Permits to work

All work must be carried out or be supervised by a suitably competent person.

Installation and operating personnel should be trained in the correct use of the product according to the Installation and Maintenance Instructions.

Where a formal ‘permit to work’ system is in force it must be complied with. Where there is no such system, it is recommended that a responsible person should know what work is going on and, where necessary, arrange to have an assistant whose primary responsibility is safety.

Post ‘warning notices’ if necessary.

1.12 Handling

Manual handling of large and/or heavy products may present a risk of injury. Lifting, pushing, pulling, carrying or supporting a load by bodily force can cause injury particularly to the back. You are advised to assess the risks taking into account the task, the individual, the load and the working environment and use the appropriate handling method depending on the circumstances of the work being done.

1.13 Residual hazards

In normal use the external surface of the product may be very hot. If used at the maximum permitted operating conditions the surface temperature of some products may reach temperatures of 239°C (462°F).

Many products are not self-draining. Take due care when dismantling or removing the product from an installation (refer to ‘Maintenance instructions’).

1.14 Freezing

Provision must be made to protect products which are not self-draining against frost damage in environments where they may be exposed to temperatures below freezing point.

1.15 Disposal

Unless otherwise stated in the Installation and Maintenance Instructions, this product is recyclable and no ecological hazard is anticipated with its disposal providing due care is taken.

1.16 Returning products

Customers and stockists are reminded that under EC Health, Safety and

Environment Law, when returning products to Spirax Sarco they must provide information on any hazards and the precautions to be taken due to contamination residues or mechanical damage which may present a health, safety or environmental risk. This information must be provided in writing including

Health and Safety data sheets relating to any substances identified as hazardous or potentially hazardous.

IM-P405-38 AB Issue 4

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2. General product information

2.1 General

The DFG300 is specifically designed for the removal of suspended / deposited solids and water from the bottom of steam boilers. The valve has been designed for spring-to-close on power failure. The manual version can be upgraded to an automatic version.

Available types

DFG300A

DN25, DN32, DN40 and DN50 steel bodied air / water actuated valve supplied with manual actuation lever.

DFG300AX

DN25 stainless steel bodied air / water actuated valve supplied with manual actuation lever.

DFG300M

DN25, DN32, DN40 and DN50 steel bodied manually actuated valve complete with lever (can be automated).

DFG300MX

DN25 stainless steel bodied manually actuated valve complete with lever (can be automated).

When used with a Spirax Sarco blowdown controller the automatic version provides timed control of suspended solids blowdown, ensuring that the recommended blowdown occurs with the minimum of heat loss and avoids duplication and omissions.

The valve can be fitted with a mechanical switchbox. This can be linked to the blowdown controller or a BMS system to indicate when the valve has not closed.

3-way solenoid valve -

A ¼" 3-way solenoid valve is an available option that may be either directly mounted on the actuator or remotely fitted.

Actuator -

The actuator incorporates a rolling diaphragm that ensures a linear operation over the full operating stroke. The actuator can be air or water actuated. The air must, however, be dry and clean. Any other non-corrosive gas can also be used as the operating medium. If water is used, it must be clean, oil and contaminant free and at a temperature of below 70 °C (158°F).

Switch box -

A switch box containing a microswitch can be optionally mounted below the actuator on a bracket, and allows connection to a blowdown controller or a building management system if required. The microswitch is set to indicate whether the valve is 'closed' or not fully closed. Note: it does not indicate that the valve is 'fully open'.

The microswitch is adjustable.

Manual override lever -

A manual override lever is provided with the DFM300 valve.

In some countries (including the UK), regulations state that only one lever is permissible within the boiler house. If more than one DFM300 valve is used additional levers should be removed from the boiler house. When not in use the lever should be removed from the valve and stored in a safe place.

2.2 Sizes and pipe connections

DN25, DN32, DN40 and DN50 flanged EN 1092 PN40.

2.3 Technical data

Solenoid valve

Supply voltage

Protection rating (with connector)

Mechanical switch

Supply voltage

Protection rating (body)

Blowdown timer

Supply voltage controller

Protection rating (housing)

24 Vdc, 24 Vac, 230 Vac or 110 Vac

IP65

600 Vac and 250 Vdc max

IP67

230 Vac or 115 Vac

IP40

2.4 Kvs values

Valve size DN25 DN32 DN40

Seat diameter 25 mm (1") 40 mm (1 ½") 40 mm (1 ½")

Kvs values 17 20 24

For conversion: Cv (UK) = Kv x 0.963 Cv (US) = Kv x 1.156

DN50

40 mm (1 ½")

30

IM-P405-38 AB Issue 4

2.5 Pressure / temperature limits

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Pressure psi g

��� ���

���

���

���

���

Steam saturation curve

� �� ��

Pressure bar g

��

��� ���

���

���

���

���

���

���

��

The product must not be used in this region.

The product should not be used in this region or beyond its operating range as damage to the internals may occur.

Body design conditions

PMA Maximum allowable pressure 40 bar g @ 120 °C

TMA Maximum allowable temperature 300 °C @ 27.5 bar g

Minimum allowable temperature

PMO Maximum operating pressure

TMO Maximum operating temperature

Ambient operating temperature range

239

-20

0

32 bar g @ 239

°C

°C

°C @ 32 bar g

°C to +90°C

PN40

(580 psi g @ 248 °F)

(572 °F @ 399 psi g)

(32

(464 psi g @ 462

(462

°F)

°F)

°F @ 464 psi g)

(-4 °F to +194°F)

Maximum operating air / water pressure 6 bar g (87 psi g)

Minimum air

Metric

Differential pressure ( P) across the valve

10 bar g

15 bar g

20 bar g

25 bar g

30 bar g

32 bar g pressure 145 psi g

217 psi g

290 psi g

362 psi g Imperial

435 psi g

Maximum temperature for a water actuated valve

464 psi g

70

°C

Designed for a maximum cold hydraulic test pressure of 60 bar g

Minimum air pressure

4 bar g

4.5 bar g

5 bar g

5.5 bar g

6 bar g

6 bar g

58 psi g

65 psi g

72 psi g

80 psi g

87 psi g

87 psi g

(158

°F)

(870 psi g)

IM-P405-38 AB Issue 4

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8

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2.6 Materials

No. Part

1

2

3

4

Body

Valve seat

A or M

AX or MX

DN25

Material

Steel

Stainless steel

Stellited stainless steel

Bonnet / yoke

DN32 to DN50 Stainless steel

Actuator housing

Steel

Pressed steel

GP 240 GH

AISI 316

ASTM A479 316

BS 970 431 S29

GP 240 GH

5

6

7

8

9

Valve head

Gland seals

Bottom cover

A or M

AX or MX

Spring guide

Spring

10 Gland follower

11 Stuffing box flange

12 Body nuts

13 Body studs

14 Body gasket

15 Diaphragm

Air / water ¼" BSP

Stellited stainless steel

Graphite rings

Steel

Stainless steel

Steel

Spring steel

Stainless steel

Steel

Steel

Steel

Graphite

Fabric reinforced nitrile rubber

ASTM A479 316

GP 240 GH

AISI 316

Fe 37B

ASTM A479 316

Fe 37B

ASTM A194 2H

ASTM A193 B7

Air / water ¼" BSP

15

Vented plug

4

Vented plug

1

9

11

10

6

8

3

1

2

9

11

10

6

2

12 14 5 7 13

Fig. 1 DFG300A and DFG300AX DN25

8

12 14 5 7 13

Fig. 2 DFG300A DN32 to DN50

IM-P405-38 AB Issue 4

3. Installation

WARNING

Read Section 1, 'Safety information' before attempting any installation.

3.1 General

The valve should preferably be installed with the actuator vertically above the pipework and having the arrow pointing in the direction of flow as indicated on the valve body, but it can also be fitted in other positions, except upside down. Install the valve between matching flanges taking care to ensure correct alignment.

The valve should be installed in such a position as to allow full access to both actuator and valve for maintenance purposes.

WARNING: The actuator housing must only be pressurised on the opposite side of the diaphragm to the springs.

The air / water supply to the solenoid valve / actuator must be in 10 mm ( ") minimum diameter pipe.

The air / water inlet connection

Actuator maximum air pressure

¼" BSP (G)

6 bar g (87 psi g)

3.2 Water actuation

For water actuation a suitable 3-way solenoid valve must be used. We recommend the

Spirax Sarco WAV1 solenoid valve.

Maximum water temperature onto the actuator should be 70 °C (158°F). If water hotter than

70 °C (158°F) is being used a cooling leg / water seal pot should be used.

A suitable water seal pot is the Spirax Sarco WS4.

3.3 Switch box -

optional extra

Refer to Figure 3 for product assembly and proceed as follows:

- Disconnect the air supply from the

pneumatic actuator.

- Loosen and unscrew the locking

grub screw and then the actuator.

- The actuator can now be removed.

- Fit the mounting bracket over the top

of the actuator yoke with the special

tongue pointing vertically downwards,

so that the bracket doesn't move.

- Then install the switch box below the

mounting bracket on the opposite side

of the yoke to the grub screw.

- Refit and fully tighten the actuator.

- Replace and tighten the grub screw.

- The mechanical switch should be

located in such a position as to allow

the correct sliding of the roller on the

upper surface of the fork arm. This

action takes place on the opposite side

of the yoke to the grub screw, towards

the hand lever connection, as shown

in Figure 3.

- Adjust the switch lever stroke so that

vertical movement of the fork causes

the switch to operate.

- Tighten the bracket bolts. Take care to

ensure that the switch roller is correctly

located, so that it slides without any

interference and always remains within

its working line of the fork arm.

- The switch terminal connections are

shown in the Installation and Maintenance

Instructions for the switch box.

Tongue

Locking grub screw

Fork

Hand lever connection

Actuator yoke

Fig. 3 Mechanical switch mounting

Actuator

Mounting bracket

Mechanical switch box

IM-P405-38 AB Issue 4

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2

3

1

15

4

4. Operation

The frequency of bottom blowdown normally depends upon the boiler operating regime and the boiler manufacturers instructions, as a minimum it is typically done once a day for up to five seconds.

The air / water supply is switched on by the solenoid valve, causing the piston to move against the spring pressure.

The valve spindle (attached to the piston) moves the valve cone away from the seat, opening the valve fully. As the valve is opened, a scraper ring removes any deposits on the valve stem protecting the seals. On release of the air / water pressure, the springs return the valve to the closed position.

The solenoid valve has an override switch, which is pushed in and then turned to lock it, allowing the DFG300A or DFG300AX to be operated independently of an electricity supply.

The manual override lever is pushed downwards to lift the stem and open the valve.

5. Maintenance

WARNING

Read Section 1, ‘Safety information’ before attempting any maintenance work.

Isolate the actuator electrically and pneumatically before any maintenance is carried out.

M6 Actuator bolts

18

8

9

11

10

6

11

10

6

Fig. 4

10

12 14 5 7 13

Fig. 5

IM-P405-38 AB Issue 4

5.1 General

Periodically check that all fasteners remain tight. No routine maintenance is required.

However periodic inspections of all parts are recommended.

5.2 Overhauling the valve

Please refer to Figure 4 for location of parts for the following replacement procedures or fitting of accessories.

1. Actuator – Ensure the actuator is vented and isolated and simply unscrew the actuator (4) from the valve.

2. Actuator diaphragm (15) – Open the actuator by removing the M6 bolts. Ensure the inside of the actuator is clean and apply grease to the operating piston and piston guide.

Replace the diaphragm and the actuator lid and replace and tighten the bolts evenly

(see Table 1 - Recommended tightening torques, page 12).

3. Gland seals (6):

- Remove the actuator (DFG300A and DFG300AX) or the stop nut on top of the manual

version (DFG300M and DFG300MX).

- Remove the lever by unscrewing the bolts attached to the spring guide (8) and the

lever hinge.

- Unscrew the spring guide lock-nut (18).

- Mark the position of the spring guide on the valve spindle. Using a screwdriver inserted

in the slot on top of the spindle to avoid rotation, unscrew the spring guide ( 8).

- Unscrew the 4 x M14 nuts and remove the spring guide, spring, stuffing box flange (11),

gland follower ( 10) and gland seals (6).

- Ensure all parts are clean, in particular the seal locating faces.

- Insert the new gland seals as shown in Figure 5. Reassembly the gland follower and

stuffing box flange taking care that the gland follower is correctly located in the stuffing

box flange.

- Re-assemble the spring and spring guide in the bonnet / yoke assembly.

- Ensure the spindle is clean and lubricated and replace the bonnet gasket. Carefully

assemble the Yoke assembly over the spindle.

- Using the screwdriver to avoid rotation of the spindle tighten the spring guide

until it is at it’s original marked position and lock its position with the lock nut.

- Tighten the 4 x M14 nuts and replace the lever ensuring it is correctly attached to the

spring guide.

- Replace the actuator (DFG300A and DFG300AX) or the stop nut (DFG300M and

DFG300MX).

Warning: Do not operate the lever without the actuator or stop nut reassembled.

4. Replacement of the switchbox:

- Isolate the electrical supply.

- Disconnect the wiring to the switchbox.

- Unscrew the 4 screws that attach the switchbox to the square support bracket.

- Mount and attach the new switchbox.

- Adjust the position of the lever in order to operate the switch at the desired position.

- If further adjustment is required loosen the screws on the support bracket that connects

to the yoke and move the switch box assembly. Tighten the screws when the desired

position is reached.

- Restore the electrical connections and the electrical supply.

IM-P405-38 AB Issue 4

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6. Spare parts

Spare parts

The spare parts available are detailed below. No other parts are supplied as spares.

Available spares

Stuffing box packing (3 off)

Actuator diaphragm

Gaskets kit (2 sets)

Mechanical switch (without mounting kit)

Manual actuation lever

6

15

14

How to order spares

Always order spares by using the description given in the column headed 'Available spares' and state the type and size of the valve.

Example: 1 off Actuator diaphragm for a Spirax Sarco DN40 DFG300A automatic boiler blowdown valve.

15 15

6

6

14

Fig. 6 DFG300A and DFG300AX DN25

14

Fig. 7 DFG300A DN32 to DN50

Table 1 Recommended tightening torques

Part

Actuator bolts

Body nuts

Lever hinge nuts

Spring guide

12

10 A/F

22 A/F

17 A/F

10 A/F

mm

M6

M14

M10

M12

N m lbf ft

5 - 6

70

5

25

3.5 - 4.5

51.5

3.5

18.5

IM-P405-38 AB Issue 4

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