THERMOSTATIC BIMETALLIC STEAM TRAP

1 N4000 THERMOSTATIC BIMETALLIC STEAM TRAPINSTALLATION, SERVICING AND MAINTENANCEINSTRUCTIONS1 velan Valves LtdLeicester, EnglandINSTALLATION, SERVICING AND MAINTENANCEINSTRUCTIONSCONTENTSPAGE1. FEATURESa. Fast Warm Upb. Positive STEAM Trappingc. Condensate Discharged. Check Valve44552. INSTALLATION AND OPERATION63. ADJUSTMENTa. Bi-metal/valve clearanceb. High Back Pressure9114. MAINTENANCEa. Testing of Valve Seat and Gasketb. Removal of Bimetalc. Repair of Valve and Valve Seatd. Re-assembly121214165. TOOL part NUMBERS17 THERMOSTATIC TRAPMODEL N400036. BOLTING TORQUESBack PageQUICK REFERENCE2 QUICK REFERENCE - Handling, Storage, Installation and Operating is necessary to read and understand the following instructions prior to working on the information is available in the GoodsAll traps must be inspected upon reception fordamages that may have occured during transporta-tion or handling.

2 Any damage noted should bedocumented; serious damage should be reportedimmediately to velan Valves and HandlingTraps should be stored in a suitable shelteredlocation to prevent contamination by weather, damp-ness or foreign material. All traps are shipped fromVelan factory with end protectors on the inlet andoutlet. These protectors should remain on the trapuntil they are ready for installation. For large traps ahoist and nylon slings are needed. Place a nylonsling under the trap body and hoist vertically to moveto final , Installation & OrientationAll traps have direction of flow indicated by an arrowon the to installation, remove end protectors, cleanweld prep, threads, and flanges using rags withunused acetone or alcohol.

3 (During welding andconstruction stages trap should be protected fromforeign debris getting inside, that could cause exten-sive damage during operation.)Ensure that the traps are installed in the properorientation, arrow pointing in the direction of that trap materials of construction andpressure/temperature limits shown on the nameplateare suitable for the intended all mating flange fasteners in a diagonalpattern and check bolting torques and retighten asnecessary after minimum distance of 2-3 feet ( ) of conden-sate pipe at the inlet end of the trap should not beinsulated, otherwise the trap performance will large traps, due to weight additional local supportmay be required on site by MaintenanceTraps should be inspected regularly during operationand should be subjected to schedule PartsAll parts on any STEAM trap can be ordered.

4 Correctlydetermine which parts are required and provide theinformation shown on the trap safety reasons, it is important to take the follow-ing precautions before you start to work on the trap should wear suitable safetyequipment while making any adjustment tothe , drain and vent the line, beforeworking on the trap should be fully isolated from thesystem before removing any cover/plugs orloosening bolts. Check isolation valves arelocked to prevent accidental supports attached to the trap arethe responsibility of the end warning notices or safety guards arein place to avoid personnel, touching the trapwhilst in operation.

5 Traps get very the trap is installed in the correctdirection of the - OEM parts are not / national rules must be followed duringinstallation and servicing. If in doubt seekadvice from your safety , SERVICING AND MAINTENANCEINSTRUCTIONSMODEL N40001. FEATURESThe Type N Trap range is particularly suitable for high pressure/high temperaturetrapping applications in power plants, marine applications, superheated mains andother equipment. The forged steel design and stainless steel parts, stellite faced,assure long life under severest GasketS/S Spiral woundNon-Asbestos fillerCover : Forged Alloy Steel(F91)Strainer : Stainless SteelRocker :Stainless SteelWelded SeatStainless Steel/StellitedValve Assembly :Stainless SteelBimetal Element :Ruflex GB14 Body : Forged AlloySteel (F91)Bottom Plugs : AlloySteel (F91)Stud : Alloy SteelSpring Washer :Stainless SteelCap Nut.

6 Alloy SteelAs for saturated STEAM , but the higher STEAM temperature increases bimetal pulland shuts the valve even Fast warm up with automatic air ventingWhen cold the bi-metal relaxes and the discharge valve is wide open allowing air,gasses and cold water to clear quickly, ensuring no air binding or water logging occursto delay equipment warm up. STEAM wasting by-passes, or other secondary air ventingsystems are Positive STEAM Trappingi : Saturated SteamIncoming STEAM contacting the bimetal element causes the bimetal to deflect anddevelop thermal power to act on the valve stem, overcoming the line pressure and close thevalve tight.

7 The power of the bimetal element increases or decreases as a function of thesaturated STEAM temperature. The same element operates efficiently at any given pressurewithin its : Superheated steam5c. Condensate DischargeCooler condensate gradually reduces the bimetal force until the unbalanced pressureon the valve cracks the orifice and releases the flow. This is the first stage of thesmooth opening. The second stage occurs as the flow is released , the unbalancedpressure acts on the full valve area, increasing its force, fully opening the orifice formaximum capacity Check ValveFor traps installed in a condensate return system, or a multiple collection header,excess back pressure, traps discharging on different cycles, a drop in line pressureor discharge to overhead return lines, can cause a reverse flow of condensatethrough the trap.

8 Separate check valves are required down-stream of the trap toprevent this occurring. However the free floating self heating valve inside the velan trapwill close immediately reverse flow is present and no additional valve is Pocket5-8 Pocket62. INSTALLATION AND OPERATIONb. Install the trap 5' - 8' ( - ) from the equipment drain point when possible. The minimum distance is 24inches ( ). This cooling leg acts as a storage chamber improving the trap operation. Figures 7 and 8 indicate correct methods for collecting condensate from STEAM mains, ensuring that most of the condensate flowing along the main can be Secondary air vents, check valves and strainers are not necessary, as these are standard feature of the The trap can be installed in any convenient position (see fig 5).

9 In the vertical position with the inlet on top, the trap is self-draining and therefore freezeproof, provided the condensate can drain away (see fig 6). Direction of flow is indicated by arrows- integrally forged on the All position Self drainingDue to the weight of the trap additional local support may berequired on site by Piping King UnitStandard Bypass Configuratione. Blow out the line or unit with air, or STEAM if possible, before installing the trap, to remove dirt and Where a bypass is required the equivalent piping king should be used. This provides considerable savings in space and construction costs compared to a conventional bypass, (see fig 9).

10 The piping king unit allows in line 9f. The trap and at least the last 2 - 3 feet ( - ) of the cooling leg should not be insulated, otherwise the trap performance will be It is not necessary to disassemble the trap when welding into position. However correct weld procedures must be used without excessive heat When operating, the trap will adjust to the quantity and flow condition of the condensate. If intermittent, the trap will discharge intermittently. However if condensate flow is continuous the trap will also discharge 10i. For checking the trap operation when installed in a closed return system a test valve can be fitted as shown as in fig 10.