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Integral Valve InterlocksApplication Data Sheet
Black Liquor Recovery Boilers
In the paper and pulp industries, black liquor recovery boilers are used to burn the black liquor from the processing plant to provide additional steam and to recover sodium salt from the liquor. If conducted improperly, this process could result in a reaction between water and sodium salt, low solid liquors, or the uncontrolled ignition of unburned fuel and gases which could cause a furnace explosion. Due to the complexity and high risks of this process, careful control of the operations are required to ensure safety.
To minimize the possibility of an explosion, the control of the black liquor injection guns and the flow of the black liquor through the indirect liquor heater or washout procedures are synchronized by using the KIRK Eagle Series valve interlocks and access interlocks.
A typical black liquor recovery process using a KIRK® trapped key interlock system is detailed on the reverse of this page.
www.kirkkey.comProcess safety Control
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esPulp
Paper
Kraft
Multi-Turn Valve Interlock
Type DM Access Interlock and Latch Bolt
Quarter-Turn Valve Interlock
INITIAL SYSTEM STATUS: i) Liquor gun ports are all locked closed – Key A is trapped in the switch / solenoid unit.ii) Liquor supply / washout system – Supply Valves V1, V2, V4 & V5 are locked open.
Bleed Valves V3 & V6 are locked closed. Washout connections isolated and spool pieces removed. Key B trapped in the switch lock.
Interlocking Logic
Operation
Integral Valve interlocksApplication Data Sheet
Interlocking Sequences can be designed to suit any operational or Process Requirements
Global Headquarters | 9048 Meridian Circle NW | North Canton, OH 44720 | USA 800.438.2442 | FAX 330.497.4400 | [email protected]
Black Liquor Recovery Boilers
SYSTEM OPERATION: To Operate Black Liquor Guns 1) The operator is given a Permit to Work (PtW)
and a permissive is given from Control to operate the switch / solenoid and release Key A.
2) Key A is then entered into any one of the Recovery Boiler Gun Ports to allow black liquor to be supplied to furnace. Note: If more than one port is to be used at anytime, a Key exchange box will be included in the system.
3) On completion of firing black liquor, reverse the process to obtain Key A and enter into the switch / solenoid key release unit to signal to Control that all liquor guns are out of furnace.
SYSTEM OPERATION: To Preform Water Washout Procedure 1) The operator is given a Permit to Work (PtW)
and a permissive is given from Control to operate the switch / pump to OFF position and release Key B.
2) The operator enters Key B into supply valve V1 to unlock and allow valve to be closed. Lock valve open by removing Key C.
3) The operator continues in sequence through the supply and bleed valves using the keys to open or close them until Key G is released. The liquor supply is now isolated for water washout.
4) The spool pieces are now inserted in the wash connection pipelines and the isolation valves opened to allow washing to proceed. Note: The spool pieces and associated wash valves may also be part of the interlock system depending on plant requirements.
5) When washout is completed, reverse the procedure and enter Key B into the switch / pump and turn pump ON.
LegendDual Key Valve Locked Open
Dual Key Valve Locked Closed
Key Free Key Trapped
The interlocking logic shown illustrates a typical black liquor arrangement with washout connections. Note: The operating details given below should be read in conjunction with the logic diagram above.
DE
C B C D
GH
E F F G
A A A A
AON
OFF
BON
OFF
Liquor to Boiler
Spool Pieces RemovedMay Also be interlocked
Wash Connections
Valve V1 Valve V2 Valve V4 Valve V5
IndirectHeater
Recovery Boiler Gun PortsNumber of Ports Dependent on Boiler Design
Bleed Valve V3
Pump
Bleed Valve V6
Key SwitchPump Control
Key Switch / SolenoidKey Release Unit
FiringAccess Door
FiringAccess Door
FiringAccess Door
FiringAccess Door
Integral Valve InterlocksApplication Data Sheet – Tanker Loading/unloading
Road / Rail / sea Tankers
The transportation of bulk toxic or flammable products by road, rail or sea is common practice today. The most dangerous part of this transportation is the loading or unloading of the tanks when spillage or leakage of hazardous gases or liquids can cause injury to humans and / or potentially explosive situations to occur.
Product transfer procedures for these materials are typically controlled by manual operations which leave all responsibility for safe control of the process in the hands of the operators concerned.
The use of Kirk Key Eagle Integral Valve Interlocks together with Kirk Key mechanical and electro-mechanical interlocks on loading/unloading systems is a proven way to safely control this type of application throughout the world. The use of Kirk Key Interlocks will control a defined sequence of equipment operation to minimize or eliminate hazards involved in any system.
www.Kirkkey.comProcess safety Control
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esOil Refinery
Petro-Chemical
Pulp & Paper
Liquefied Gases
Multi-Turn Valve Interlock
Quarter-Turn Valve Interlock
Key 1
Key 3
Key 3 Key 2
Key 2
Key 4
Key 5
GladhandSupervisorControl
SupervisorControl
Valve B
Valve A
Tanker Loading/Unloading cannot commenceuntil gladhand is in locked position,
pipeline valves are openedand pump motor is energized
Pump Starter
The interlocking logic shown above illustrates a typical loading/unloading arrangement.
INITIAL SYSTEM STATUS: The pump starter is in the ‘OFF’ position. Valves A & B are locked in the closed position. The loading/ unloading area is vacant. The Supervisory Control Key 1 is held in Control with the Glad Hand Trailer Brake Lockout Unit (GHU).
SYSTEM OPERATION: 1) The tanker driver is instructed to enter
the loading facility.
2) The system operator issues the GHU with Key 1, Key 2 is trapped in the GHU. The unit is attached to the tanker emergency brake line connection to lockout the tanker brakes—locking the tanker in place. When correctly connected Key 2 is release from the GHU.
3) The operator then inserts Key 2 into lock fitted to Valve A to unlock, and allow the valve to be opened. The valve is locked open by removing Key 3.
4) The operator inserts Key 3 into lock fitted to the Valve B to unlock and allow the valve to be opened. The valve is locked open by removing Key 4.
5) Finally the operator inserts Key 4 into Pump Starter Switch to allow the power to the pump to be turned ‘ON’. The Pump Starter is locked in the ‘ON’ position by removing Key 5 which is returned to Supervisory Control.
6) After completion of the loading/ unloading operation the sequence is reversed to allow the tanker to exit the facility maintaining safe spill free operation.
Interlocking Logic
Operation
Integral Valve interlocksApplication Data Sheet – Tanker Loading/unloading
Road/Rail Barriers
Hose
Gantry Access
valve
Electrical Switch for Pumps
Interlocking designs can be made to suit any operational Requirements
Typical tanker loading/ unloading systems can include any of these locks or interlocks.
www.Kirkkey.com
Road / Rail / sea Tankers
Global Headquarters | 9048 Meridian Circle NW | North Canton, OH 44720 | USA 800.438.2442 | FAX 330.497.4400 | [email protected]
Integral Valve InterlocksApplication Data Sheet
Rail Tanker Interlocking
Transportation of hazardous liquids by rail over long distances is a growing practice which requires careful control of both loading/unloading and security of the products in transit.
During loading/unloading there are often set procedures to be followed to ensure a particular product is handled correctly. The sequence of operation when loading/unloading is usually carried out manually so the possibility for error can be high.
Using KIRK® Eagle Valve Interlocks and Trapped Key Interlock systems can be designed to completely control an operation safely in the correct sequence.
A simple system for controlling loading/unloading a rail tanker valve using a KIRK® trapped key interlock system is detailed on the reverse of this page.
www.kirkkey.comProcess safety Control
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esRail Tankers
Rail Loading/ unloading terminals
Multi-Turn Valve Interlock
Type DM Access Interlock and Latch Bolt
Quarter-Turn Valve Interlock
Integral Valve interlocksApplication Data Sheet
Interlocking Sequences can be designed to suit any operational or Process Requirements
Global Headquarters | 9048 Meridian Circle NW | North Canton, OH 44720 | USA 800.438.2442 | FAX 330.497.4400 | [email protected]
Rail Tanker Interlocking
INITIAL SYSTEM STATUS: Tail Tanker Hatch is locked closed, with Key B trapped in the lock, the loading/unloading valve is locked closed.
SYSTEM OPERATION: To Load/Unload Tanker 1) Rail Tanker is locked in position at Rail Tanker is locked in position at loading/unloading station. (This can be by the use of rail chocks which could also form part of the interlock system).
2) Key A is issued from ‘Control’ and entered and rotated in the Access Lock fitted to the top hatch. This allows the locking chain to be released and the hatch opened. In addition this action releases Key B.
3) Enter Key B into Load/Unload Valve to unlock and allow valve to be opened, lock valve open by removing Key C.
4) If required Key C can be used to operate hose coupling lock and/or other valves in the loading/unloading station.
5) On completion of loading/unloading operation reverse the sequence to prepare the rail tanker for movement.
Interlocking Logic
Operation
LegendDual Key Valve Locked Open
Dual Key Valve Locked Closed
Key Free Key Trapped
The interlocking logic shown illustrates a simple rail tanker interlocking system. Note: The operating details given below should be read in conjunction with the logic diagram above.
B C
BA
Pump
KIRK® Type QT or MT Valve Lock fitted to Rail TankerLoading/Unloading Valve
KIRK® Type DM Access Lock withchain securing Access Hatch Lid Closed
Eagle Locks are available for Valves, Closures, Electrical Switches and many other applications contact Kirk Key Interlocks or your Local Representative for additional help with your requirements.
Integral Valve InterlocksApplication Data Sheet
Pressure relief safety valve
In many petro-chemical and chemical plants duplication of process components is used to ensure continuous operation. The aim being to run plants for extended periods of time, years or more, without shutting down.
One of the classic examples of duplication is the use of dual or multiple pressure relief safety valves (PSVs) on process vessels and tanks to ensure safety of operation. An additional requirement of having dual PSVs is that one or more relief valves must always be in service to maintain safety.
There are several ways of ensuring that a PSV is always in service, the simplest being to use standard manual block valves fitted with key operated valve interlocks. The Kirk range of Eagle Valve Interlocks can be supplied to mount directly on to the system block valves with the locks keyed to maintain the operational requirements of a relief valve system.
Quarter-Turn or Multi-Turn valve interlocks being used dependent on the type of valve which they are controlling – Quarter-Turn for ball, plug or butterfly valves or Mutli-Turn for gate, globe or gearbox operated valves.
Please see overleaf for details of operation of a typical dual PSV system. Other key logics can be supplied for multiple PSVs.
www.Kirkkey.comProcess safety Control
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Petro-Chemical
Pulp & Paper
Liquefied Gases
Food Bulk Handling
Multi-Turn Valve Interlock
Quarter-Turn Valve Interlock
INITIAL SYSTEM STATUS: PSV “B” is in service and PSV “A” is isolated for maintenance. Valves 1 & 2 are locked closed, valves 3 & 4 are locked open. Key A is held under Supervisory Control.
SYSTEM OPERATION: 1) Key A is issued to an operator from
the Supervisor in the Control Room together with a Permit to Work (PtW)
2) The operator enters Key A into the lock fitted to Valve 1, to unlock and allow the valve to be opened. Key B is removed from the lock to lock the valve open.
3) The operator enters Key B into the lock fitted to Valve 2, to unlock and allow the valve to be opened. Key C is removed from the lock to lock the valve open.
4) The operator enters Key C into the lock fitted to Valve 3, to unlock and allow the valve to be closed. Key D is removed from the lock to lock the valve closed.
5) The operator enters Key D into the lock fitted to Valve 4, to unlock and allow the valve to be closed. Key E is removed from the lock to lock the valve closed.
6) Key E is returned to the Supervisor in the Control Room to signify the operation has been completed.
7) PSV “A” is now in service and PSV “B” is isolated for maintenance.
8) The sequence can be reversed to return to the initial system status.
Interlocking Logic
Operation
Integral Valve interlocksApplication Data Sheet
Interlocking designs can be made to suit any operational Requirements
www.Kirkkey.com
Pressure Relief Safety Valve
The interlocking logic shown illustrates a typical operational sequence for a dual pressure relief system.
D E
CD B
C
A B
E
A
Supervisory Control
Valve 3LockedOpen
Valve 2LockedClosed
Valve 4LockedOpen
Valve 1LockedClosed
Pressure Vessel
To Flare
PSV “A”In Service
PSV “B”In Service
PSV “B”Isolated
PSV “A”Isolated
In ServiceKey Held Isolated
Key A
Key B
Key C
Key D
PSV “B”
PSV “A”
Key E
LegendDual Key Valve Locked Open
Dual Key Valve Locked Closed
Key Free Key Trapped
STEP
1
2
3
4
A
B
C
B
A B C
B
C
B
A
KEYIN
KEYOUT
SequenceControl Unit
H2 Valve CO2 Valve Air Valve
Operating Knob
STEP
1
2
3
4
A
B
C
B
A B C
B
C
B
A
KEYIN
KEYOUT
SequenceControl Unit
H2 Valve CO2 Valve Air Valve
Operating Knob
Global Headquarters | 9048 Meridian Circle NW | North Canton, OH 44720 | USA 800.438.2442 | FAX 330.497.4400 | [email protected]
Integral Valve InterlocksApplication Data Sheet
Motor Pump Start-up
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In many industries electric / pneumatic powered pumps are used to move products around a plant or production area. The operation of the pump against a closed pipeline or the maintenance of the motor / pump set when the product is not isolated can lead to disastrous results both in loss of product and damage to plant / equipment.
Valve interlocks used in-conjunction with motor power switch locks can avoid these costly accidents occurring and ensure the correct procedures are used at all times.
The arrangement shown overleaf is a typical interlocking system for this type of application. Many variations on this theme can be adapted to suit individual plant / site processes.
www.Kirkkey.comProcess safety Control
Oil Refinery
Petro-Chemical
Pulp & Paper
Production Plant
Multi-Turn Valve Interlock
Quarter-Turn Valve Interlock
Panel Mounted Switch
The interlocking logic shown above illustrates a typical pump set arrangement.
INITIAL SYSTEM STATUS: Normal operation: The motor/pump is running and both valves are locked and in the open position. Key 1 is held in the control room.
ISOLATION OF SYSTEM: For Maintenance or shut-down: 1) Key 1 is issued to an operator from the
Control Room.
2) Key 1 is inserted into lock fitted to pump starter switch to unlock, the switch is operated to the ‘OFF’ position which releases Key 2.
3) Operator inserts Key 2 in lock fitted to the Valve A to unlock and allow the valve to be operated to the clsed position. Remove Key 3 to lock the valve closed.
4) Insert Key 3 into Valve B to unlock and allow the valve to be operated to the closed position. Remove Key 4 to lock the valve closed.
5) Return Key 4 to the Control Room to signify that it is safe to work on the pump set.
6) After completion of the maintenance reverse the procedure to put the pump set online.
Interlocking Logic
Operation
Integral Valve interlocksApplication Data Sheet
Interlocking designs can be made to suit any operational Requirements
www.Kirkkey.com
Motor Pump Start-up
Key 1
Key 2 Key 3
Key 4
Supervisor Control
Supervisor ControlIsolate Power
Close Valve AClose Valve B
Safe to perform maintenance
Valve A
Valve B
Global Headquarters | 9048 Meridian Circle NW | North Canton, OH 44720 | USA 800.438.2442 | FAX 330.497.4400 | [email protected]
Integral Valve InterlocksApplication Data Sheet
LOTO VALVE Isolation
Many industries have equipment and machines that use pneumatics to control their operations. When maintenance or access is required to the area it is nec-essary to isolate and vent the air supply. Typically, a 3-way lockout valve is installed on the supply line to properly vent the air. When the red manual control on the lockout valve is operated, the air supply is isolated and the machine supply line is vented.
Normal practice to lockout the system is to use a padlock. Applying the padlock to the lockout valve limits any additional controls, isolation, or access requirements to be applied to other areas of the equipment for work to be performed safely. The incorporation of a KIRK® trapped key interlock on the lockout valve prohibits valve operation and the KIRK® interlock key can then be used to initiate lockout procedures and allow access to other parts of the equipment, providing a safe working environment for all tasks needing to be performed.
See the reverse side for a step by step procedure and illustration of this process application.
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Manufacturing
KIRK® Trapped Key Interlocks for use together with Lockout Valves
Lockout Valve fitted with KIRK® Trapped Key Inter-lock
NORMAL SYSTEM STATUS: Lockout valve is open with air flowing through Inlet Port 1 to Outlet Port 2 and he handle extended with Exhaust Port 3 blocked. The Kirk Trapped Key Bolt lock is in the retracted position with the Key A trapped in the lock.
SYSTEM LOTO OPERATION for MAINTENANCE: 1) The Operator pushes the handle inwards to the valve body which blocks Inlet Port 1
and directs flow from Outlet Port 2 to exhaust via Exhaust Port 3.
2) Key A is now turned in the Kirk Key Bolt Lock to extend the bolt and engage the locking ring on the lockout valve handle. This allows Key A to be released and permanently locks the valve in the exhaust position.
3) Key A is released and can then be used to operate additional locks in a system to allow safe access to a machine or equipment.
Interlocking Logic
Operation
Integral Valve interlocksApplication Data Sheet
Interlocking designs can be made to suit any operational Requirements
Global Headquarters | 9048 Meridian Circle NW | North Canton, OH 44720 | USA 800.438.2442 | FAX 330.497.4400 | [email protected]
LOTO Valve Isolation
Legend
Key Free Key Trapped
Note: The KIRK® bolt lock mounting will vary depending on the make and model of lockout valve used.
AA
InletPort 1
ExhaustPort 3
OutletPort 2
InletPort 1
ExhaustPort 3
OutletPort 2
Manual Handle Extended
EquipmentAir Supply
Air Supply EquipmentAir Supply
Air Supply
KIRK® BOLT INTERLOCK
KIRK® BOLT INTERLOCK
Manual Handle Operated
Valve Unlocked in Normal Position Valve Locked for Maintenance
Integral Valve InterlocksApplication Data Sheet
HYDROGEN COOLED GENERATOR PURGE
Using Kirk Key Eagle Series will ensure the proper procedures are performed for a hydrogen cooled generator purge and maintain the efficiency of the electric generators and a safe working environment. By purging the rotating system with hydrogen, this reduces the drag or windage loss in the system.
Prior to start up or for maintenance, it is necessary to introduce air to provide a safe working atmosphere. This cannot be done directly into the hydrogen as an explosive atmosphere will be created with the corresponding hazards involved. To remove the hydrogen from the generator, either Carbon Dioxide or Nitrogen is purged through the system. Once the hydrogen has been purged by CO2, it is then replace with air. Kirk Key Eagle Series interlocks should be fitted to the gas control valves and incorporating the Nonlinear Transfer Unit (NLTU) will ensure the correct sequence of operations is followed.
The typical operation for a system is shown on the reverse of this page.
www.kirkkey.comProcess safety Control
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Multi-Turn Valve Interlock
Quarter-Turn Valve Interlock
Nonlinear Transfer Unit
INITIAL SYSTEM STATUS: The Carbon Dioxide (CO2) and Air Valves are locked closed and the relevant keys held in the Nonlinear Transfer Unit (NLTU). The Hydrogen (H2) Valve is open with Key A trapped in the valve lock.
SYSTEM OPERATION: 1) When initiating the H2 Purge Operation, the
H2 Valve is closed and locked closed byremoving Key A.
2) Enter Key A into the NLTU and step the unit once to release Key B.
3) Key B is entered into the lock fitted to theCO2 Air Valve to unlock and allow it to beopened. When open, Key B is trapped andcannot be removed until the valve is closed.
4) On completion of the CO2 Air Valve purge,operation to the CO2 Air Valve is closed andlocked by removing Key B.
5) Enter Key B into the NLTU and step the unit once to release Key C.
6) Key C is entered into the lock fitted tothe Air Valve to unlock and allow the valveto be opened. When the valve is open,Key C is trapped and cannot be removeduntil the lock is closed.
7) On completion of the air purge, operationto the Air Valve is closed and locked byremoving Key C.
8) Enter Key C into the NLTU and step the unit once to release Key B.
9) Key B is entered into the lock fitted to theCO2 Air Valve to unlock and allow it to beopened. When open, Key B is trapped andcannot be removed until the key is closed.
10) On completion of the CO2 Air Valve purge,operation to the CO2 Air Valve is closed andlocked by removing Key B.
11) Enter Key B into the NLTU and step the unit once to release Key A.
12) Key A is entered into the lock fitted tothe H2 Valve to unlock and allow it to beopened. When open, Key A is trapped andcannot be removed until the valve is closed.
Interlocking Logic
Operation
Integral Valve interlocksApplication Data Sheet
Interlocking Sequences can be designed to suit any operational Requirements
Global Headquarters | 9048 Meridian Circle NW | North Canton, OH 44720 | USA 800.438.2442 | 330.833.1528 | [email protected]
HYDROGEN COOLED GENERATOR PURGE
STEP
1
2
3
4
A
B
C
B
A B C
B
C
B
A
KEYIN
KEYOUT
SequenceControl Unit
H2 Valve CO2 Valve Air Valve
Operating Knob
The interlocking logic shown illustrates a typical generator purge valve system.Note: The KIRK Nonlinear Transfer Unit (NLTU) is a key release unit which ONLY releases keys in a predetermined sequence, the operating knob ONLY rotates in one direction to release the keys.
LegendSingle Key Valve Locked Open
Single Key Valve Locked Closed
Key Free
Key Trapped
STEP
1
2
3
4
A
B
C
B
A B C
B
C
B
A
KEYIN
KEYOUT
SequenceControl Unit
H2 Valve CO2 Valve Air Valve
Operating Knob
STEP
1
2
3
4
A
B
C
B
A B C
B
C
B
A
KEYIN
KEYOUT
SequenceControl Unit
H2 Valve CO2 Valve Air Valve
Operating Knob
Integral Valve InterlocksApplication Data Sheet
Dual Line Valves
In many industrial plants tanks and processes are supplied by multiple pipelines. These pipelines often require strict controls to ensure the correct product is supplied to or from the correct tank or process.
This can be accomplished simply by the installation for Kirk Eagle Valve Interlocks on the relevant valves in the pipelines. Quarter-Turn or Multi-Turn valve interlocks being used dependent on the type of valve which they are controlling—Quarter-Turn for ball, plug or butterfly valves or Multi-Turn for gate, globe or gearbox operated valves.
The operating key logic shown overleaf is typical for a pair of valves controlling two pipelines. Similar systems can be engineered to suit other applications with multiple pipelines and valves.
www.Kirkkey.comProcess safety Control
Indu
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esOil Refinery
Petro-Chemical
Pulp & Paper
Liquefied Gases
Food Bulk Handling
Multi-Turn Valve Interlock
Quarter-Turn Valve Interlock
Key 1Key 2
Key 3
One Valve OpenOne Valve Closed
Supervisor Control
The interlocking logic shown above illustrates a typical operational sequence for a pair of valves.
INITIAL SYSTEM STATUS: Valve A is locked closed and Valve B is locked open with Key 1 held in the Control Room under Supervisory Control.
SYSTEM OPERATION: 1) Key 1 is issued to an operator from
the Control Room together with a Permit to Work (PtW)
2) The operator enters Key 1 into the lock fitted to Valve A, to unlock and allow the valve to be opened. Key 2 is removed from the lock to lock the valve open.
3) The operator enters Key 2 into the lock fitted to Valve B, to unlock and allow the valve to be opened. Key 3 is removed from the lock to lock the valve open.
4) Key 3 is returned to the Control Room to signify the operation has been completed.
5) The sequence can be reversed to return to the initial system status.
NOTE: Dependent on system requirements key interlocks/valves can be set-up for either both valves open at change-over or both valves closed at change-over.
Interlocking Logic
Operation
Integral Valve interlocksApplication Data Sheet
Interlocking designs can be made to suit any operational Requirements
www.Kirkkey.com
Dual line valves
Global Headquarters | 9048 Meridian Circle NW | North Canton, OH 44720 | USA 800.438.2442 | FAX 330.497.4400 | [email protected]
Integral Valve InterlocksApplication Data Sheet
Boiler Blow-Down Valves
Industrial boilers often have several manual blow-down valves to perform the process of removing sludge from the boiler. This regularly performed process of manual blow-down of the bottom of a boiler can become a very dangerous situation if not completed correctly. For the operations to be carried out safely and without incident, only one valve should be opened at any time to prevent the blow-down fluid from being directed back into the boiler.
Using Kirk Key Eagle Valve Interlocks, as shown in the application scheme overleaf, will ensure that the proper sequential procedure is followed to perform the blow-down process.
www.kirkkey.comProcess safety Control
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esPower Generation
Process Plant
Industrial Boilers
Multi-Turn Valve Interlock
Quarter-Turn Valve Interlock
INITIAL SYSTEM STATUS: All valves are locked closed with Key A held in the Control Room.
SYSTEM OPERATION: 1) Key A is issued from Control with instruction to operate
blow-down valve 1, 2 or 3.
2) Enter Key A into blow-down valve 1, 2 or 3 and operated the valve to the open position. Key A is trapped in the valve lock when the valve is open so it cannot be used to operate any other valve.
3) Once the blow-down operation has veen completed, close the valve and lock closed by removing Key A.
4) Repeat operation for other blow-down valves.
5) On completion of operation all blow-down valves return Key A to Control to confirm the process is completed.
Interlocking Logic
Operation
Integral Valve interlocksApplication Data Sheet
Interlocking Sequences can be designed to suit any operational or Process Requirements
Global Headquarters | 9048 Meridian Circle NW | North Canton, OH 44720 | USA 800.438.2442 | FAX 330.497.4400 | [email protected]
Boiler Blow-Down Valves
The interlocking logic shown illustrates a typical boiler 3 valve blow-down valve system.
Note: All valve locks to be single key locks; Key Free valve locked closed.
LegendSingle Key Valve Locked Open
Single Key Valve Locked Closed
Key Free Key Trapped
STEP
1
2
3
4
A
B
C
B
A B C
B
C
B
A
KEYIN
KEYOUT
SequenceControl Unit
H2 Valve CO2 Valve Air Valve
Operating Knob
STEP
1
2
3
4
A
B
C
B
A B C
B
C
B
A
KEYIN
KEYOUT
SequenceControl Unit
H2 Valve CO2 Valve Air Valve
Operating Knob
A
Key “A” HeldIn Control
A A A
Boiler
Blow-DownValve 1
Blow-DownValve 2
Blow-DownValve 3
Drain