Liquid Drain Traps - Spirax Sarco International

1 Liquid Drain Trapsfor effective draining of liquids from gases2 Automatic and continuous Drain trap oMany industrial processes involve theremoval of a Liquid from a pressurized most common example is compressedair. Atmospheric air always contains somewater vapor. When the air is compressedand cooled, it can hold less moisture. Theexcess water vapor condenses to form liquidwater. This water is harmful to the distribution system and the pneumaticequipment. A Liquid Drain trap is used todrain off the water while preventing theescape of compressed the majority of small Liquid DrainTraps are used on compressed air systems,there are many other industrial applicationswhich require the drainage of a Liquid fromeither its own vapor phase or some other Sarco automatic float-operated liquiddrain Traps are ideally suited for this Traps can handle liquids with a specificgravity as low as , and they are available ina wide variety of sizes.

2 End connections andconstruction internal parts can be serviced without disturbingthe pipe connectionsStainless steel float automatically adjusts thevalve opening to maintain acontinuous Liquid flowStainless steel valve mechanismMoistureSeparatorIsolating valveUnionBalance PipeTo Drain orreturn lineLiquidDrainTrapStrainerDirt PocketIsolating valveGas lineDrain Traps automatically pass Liquid ,but the Liquid must first be collected andfed to the trap. In the system illustratedto the left, a Spirax Sarco moisture separator is used to knock out smallliquid droplets in the gas flow. The liquidcollects in the bottom of the separator,and from there is piped to the Drain Spirax Sarco strainer protects thetrap from dirt and pipe Liquid which backs up in theseparator may be re-entrained in thegas flow, continuous drainage is important.

3 The Spirax Sarco float draintrap is ideal for this system because itadjusts instantly and automatically toload and pressure variations. The continuous, modulated flow means thatliquid never backs up ahead of the increases system efficiencyLiquid seals the valve at all times, preventing gas leakageInstantly and automatically adjusts to variations in Liquid load and handles any load or pressure within its liquids with specific gravity as low as variety of materials and operating steel valve trim and benefits Liquid seal above the valve prevents gas be serviced without disturbing piping and sludge can be blown down periodically through the Drain tapping. An NPT balance pipe tappingis provided in the top of the bodyLiquid Drain Trap overviewPiping Piping Body (s)PMOC onnectionConfigurationMaterialReferenceF A-3030FA-753/4", 1", " 2"150 ParallelFA-2001", 1-1/2" "10 NPTIronFAB-751-1/2", 2" "175CA-141/2", 3/4" ", 3/4", 1" ", 1-1/2", 2" ",1",1-1/2",2"465 NPT, SW, ",4" ", 3/4",1", 1-1/2", 2"300 FlangedStainless " " ", 3/4",1" 200 NPT, "150 NPT, SteelTop inSide out No priming and sludge which mayaccumulate in the bottom ofthe trap may be blown downby removing the Drain plug orby installing a manual blowdown from 1/4" to 4" and capacities up to 900,000 lb/h.

4 4 Typical applications for Liquid Drain trapsDraining a compressed air receiverWater always collects in the bottom of a compressed air Liquid Drain trap is used to remove this water continuously andautomatically, while preventing the escape of compressed air. The balance pipe allows air which may enter the trap to escapeback to the receiver. Air binding can occur without a balance pipe an air orgas supply mainriserA Drain Trap should alsobe installed at the bottomof every riser. The balancepipe is connected to theriser so that it will be downstream of thedrainage point. Dip pipeTDA52 Thermo-Dynamic DrainTrapDraining an air or gassupply main downfeedLiquid can collect at pointswhere pipes carrying air orother gases change elevationor direction. If this Liquid isallowed to accumulate, theresult could be waterhammeror equipment damage.

5 A DrainTrap should be installed at thebottom of every balance pipe must beconnected to the top of thesupply main downstreamof the drainage point. Using a Drain Trapto maintain a Liquid levelA Float Drain Trap can be used to maintain a liquidlevel in a tank. In effect, the trap acts as a controlledoverflow. The balance pipe must be connected tothe tank above the maximum Liquid acompressed air receiver through a dip pipeIf floor clearance is limited, watermay be removed from the receiverthrough a dip pipe. In this case, aTDA52 Thermo-Dynamic DrainTrap is the best choice. A balancepipe is not required because theTDA52 s cyclic operation preventsair the Traps can be used to Drain most liquids form most gases, some applications, particularly those involvinghazardous or unusual fluids, may be subject to regulation or may otherwise require special consideration.

6 Spirax Sarco will endeavor to provide whatever data is necessary to assist in product (s)*Size(s)Maximum Operating Pressure, to . to . to . to . to . to . to . to . to . to .50FA/FAI-301/2",3/4",1"3531282421171410 73 1-1/2",2"343128252220171411861/2",3/4",1 "908173655749413325168FA/FAI-751-1/2"888 17366585143362821132"7560544944383328231 7121/2",3/4",1"1501421281141008671574329 15FA/FAI-1501-1/2"1501401271151039078655 340282"150139127115103917967554331 FAI-2001/2",3/4",1"200184168152135119103 87715438FA-2001"200200200190164139113886 237111-1/2"20020020019116814512299765330 FAB-102" "75696357504437312519132-1/2"75696357504 43731251913 FAB-1752"1751631501371241119885725946CA- 141/2",3/4"20019819517315213011087654526 1/2",3/4" "65656565655750392920111-1/2",2"65595347 42363024181261/2",3/4"145145145125108948 060433019-101"14514514512510793806550352 1FA4501-1/2",2"1451321191059279665340261 3CA10S1/2".

7 3/4"20319819517315213011087654526-141"20 320320318016013511392725029CA46S1-1/2",2 "2032032032032032032031659954271/2",3/4" 3043043042802612251651551167536-211"3042 9027524521718715913010066361-1/2",2"3043 043043042952532111659954273/4"4654644644 4042035030024018512565-321"4654504353853 40290246195145100551-1/2",2"465422380337 295253211165995427 CAS14/CAS14S1/2", 3/4", 1"2032032032032031621309772 FA4503",4"45045045045045045039027515840 FA-1501/4"150135119104897358432512 F-150V1/2"15015015015013811910080614223F -300V1/2"3003003003002822432031641258646 5 Liquid Drain Trap capacities selection and sizingThe discharge rate depends on the differential pressure across the trap(that is, the pressure at the trap inlet minus the pressure at the outlet). Thecapacity charts show the maximum cold water discharge rate versus thedifferential pressure.

8 Note:Although the differential pressure is used for sizing,the trap body must be designed for the full maximum system against return Line back-pressureIf the pressure in the return line (the back-pressure ) is above atmosphericat all times, the maximum operating pressure (PMO) of the trap isincreased by the amount of the back-pressure. (But the increased PMOmust never be higher than the PMA the maximum allowable pressure.)Example:If the nameplate PMO is 100 psig, and the back-pressure is always at least25 psig, the Drain trap may be used at a working pressure of up to 125 psig,provided that the nameplate PMA is at least 125 psig at the operating temperature. The excess pressure will not hold the valve closed becausethe differential pressure is not greater than the nameplate factorsBoth the amount of Liquid to be discharged and the differential pressuremay fluctuate.

9 To ensure continuous drainage during periods of high loadand/or low pressure, the Liquid Drain trap should be selected to handle theestimated load times a safety factor of at the lowest expected differential pressure. If the capacity requirements or operating conditionscannot be predicted accurately, the safety factor should be increasedaccordingly. If the maximum peak load and minimum differential pressureare accurately known, the safety factor may be reduced or other than cold waterFor liquids higher than cold water (that is, liquids with a specific gravity lessthan ), both the discharge capacity and the maximum operating pressure will be reduced. The required capacity of the light Liquid (includingthe safety factor) must be multiplied by the appropriate conversion factorfrom figure 1.

10 The resulting equivalent cold water capacity is used to selecta trap using the cold water capacity charts. Table 1 must be consulted toensure that the reduced PMO of the selected trap is higher than the expected maximum system pressure. If there is a back-pressure in thereturn line, the PMO of the trap may be increased (see above).Maximum operating pressure with light liquids*Some models are not available in all of the listed sizes. For liquids with a specific gravity less than , please consult liquidsThe capacity charts are based on single-phase ( Liquid only) flow. If thepressure/temperature conditions upstream and downstream of the trap aresuch that a portion of the Liquid will re-evaporate, or flash as it passesthrough the valve, the resulting two-phase ( Liquid and gas) flow will reducethe capacity of the trap.