ANS: - The Valve Interlock is a mechanical safety device fitted on valves to avoid unauthorized access to valves and helps in completing the procedure in sequential manner by using Trapped Linear Key Concept, thus eliminating the human error.

ANS: - YES, basically we have FOUR standard types of Interlocks


Ø Quarter Turn Lock Small & Large (QTL) used for Lever Operated Valves (Ball Valve, Butterfly Valve)

Ø Multi Turn Lock Small & Large (MTL) used for Hand-wheel operated Valves (Gate Valves, Globe Valves) and Gear Operated Valves.

Ø Special Interlocking System used for Valves below 2” size.

Ø Door Closure Lock (DCL) used for QOC door of pig launching/receiving vessels .

The mountings used to fit these locks on a Valve are custom made; hence locks can be installed on any size and type of Valve.

ANS: -Interlocks are mounted on a Valve by custom made set of mountings. This mounting set includes 1) Bracket:- connects stationary part of valve i.e. top of flange and Lock body 2) Adapt or:- which connects rotating parts of valve

i.e. Stem and Sprocket of the Lock. Both of these mountings are custom made, for   which  we   need   detailed  top    work    information    of   the    valve. No Welding or Grinding is required.

ANS: - Yes, we have solution for the same. We will install interlock on the Switch of the Actuator, Manual Override Function and Gearbox. We need details of the system to propose the solution for the same.

ANS: - Yes, we can. For Quarter Turn Valves like Ball Valve, Butterfly Valve installation of inter locks in operating condition is not a problem at all. We can install interlocks in operating condition of gas line.

However in Multi Turn valves such as Gate Valve, Globe Valve we need to set interlock for both Open and Close condition. Therefore we can install interlock on operating valve and set for either open or close condition only, to set interlock for other condition we have to operate valve.

We recommend that it is always better to install the interlock in the new plants or during maintenance or shut down of existing plant. However for  existing and operational plants the installation of interlocks can also be possible.

ANS:- Yes we can install Interlock on Quick Opening Closures using custom made set of mountings. We have specially designed Door Closure Locks for this purpose.We need details of the Quick Opening Closures to propose the solution for the same. In most cases as simple drilling and tapping on QOC outside ring is all that is needed.

ANS: - No we can’t supply interlocks for the intermediate position between open & close position of valves. We can assure locking position of valve only at open or close position.

ANS: - Yes, we can provide this service for nominal fees. Our site team measures the Top Works of existing valves and prepare the drawing for mounting the Interlock.

ANS: - The tagging on our Interlocks, Keys play a critical role. Each Key is tagged thereby helping operators in the field, during change over, to correctly identify the next step in their procedure or sequence. Tags/Nameplate on the Lock has relevant information to identify the particular System. The key that is present in the control room shows the operators the status of any particular system.

Tagging’s are provided indifferent colors and can be customized as per client’s requirement. We can put Max. 14 letters on the Tag.

ANS: - Due to extensive the experience in this field of Interlocks, Petrosafe can help and advice client on the correct operating procedures on almost all critical processes.

ANS: - Petrosafe Valve Interlocks are designed and manufactured in India. Valve Interlocks are manufactured in SS 316 material grade.The supports are designed and manufactured in SS 316 based on the dimensions of the valve  top work details provided by client.

ANS: - Yes, We can use the  existing Hand wheel or lever. Petrosafe has designed an adapter which allows use of existing hand wheel or lever. However in this case it is to be noted CS Hand wheels/Levers will mounted on the SS 316 grade equipment.

ANS: - Petrosafe requires the detailed dimensions only of the top works of the valve to design and manufacture the custom made supports. We have standard Fill In Sheets for dimensional requirements. If the valve is different from the standard valves on the sheets, we work closely with the client to make sure we get the exact requirements to do our engineering.

ANS: - A ‘.STP’ or ‘.IGS’ file gives exact dimensions of MOV/actuator which are required to design MOV Interlock mounting arrangement. It is necessary for accurate design and manufacturing of interlock mounting arrangements to avoid any mismatches during installation.  A ‘.STP’ or ‘.IGS‘ file can be open in any 3D design software.

ANS: - If operator loses a Key, you can always use the Master Key during the emergency situation. We maintain the records of all the Keys supplied during project. You can just provide us the detail engraved on the interlock along with necessary information and we will supply that key within short span of time.

ANS: -Yes, all the Keys are uniquely coded. We make sure that there is no duplication of any Key in the project.

ANS: - No, We do not use grease  or any other lubrication. This is because grease attracts dust and dirt which may cause hindrance in the operation of the Locks.

ANS: - For the purpose of warranties and to ensure proper and correct installation we recommend that Interlocks are installed by our trained and experienced Service and Installation Team. We provide On Site Training for the operators and site personnel for operating and maintaining the Interlocks.

ANS: - No, specially designed covers are fitted on the Key Opening which will not allow ingress.

ANS: - Yes, the MOC of Interlocks is SS 316 and it has good corrosion resistant properties, which can withstand any harsh environment conditions.

ANS: - Interlocks are designed and manufactured to meet the maintenance free criteria. However it is a good practice to check the operation of interlocks periodically.

ANS: - We cannot drill and tap the holes on the existing QOC of Pig Launchers and Receivers. However we can design special supports for mounting of interlocks to felicitate opening and closing of QOC in process sequence. However,client will have to provide required details.