Simplicity in steam traps can effect big savings in parts inventory and maintenance time by John W. Ritter, Test Engineer SARCO Company, Inc. The function of all steam traps is to release condensate and prevent steam loss. How ever, t h e method of trapping can make a great difference in cost a n d effectiveness. In t h e Sarco Thermo-Dynamic Steam Trap, the method is fundamental. Air or condensate entering t h e trap must flow from the inlet tube, radially across the un derside of the disc valve, to the outlet. T h e space between the inlet tube and the disc forms a nozzle in which the static pres sure energy of the incoming fluid is partly changed to velocity across the underside of the disc, with a resultant decrease in pressure. (This will be recognized, of course, as t h e Bernoulli Principle. ) Use of this fundamental method means relia bility in operation. As the high velocity fluid jet strikes the side of the upper chamber, some recom pression takes place, so that the pressure above the disc becomes greater than the pressure below it. T h e pressure reduction under the disc and the pressure recovery above it depend on the internal energy of the fluid. As t h e condensate above nearly approaches steam temperature, its internal energy is enough to overcome the upward force at the inlet tube and the disc snaps down in the inlet tube, which is t h e inlet valve seat. Simultaneously, the disc also seals t h e outer ring, which isolates the space above the disc from the outlet. T h e disc valve is therefore held firmly against the inlet valve seat until the pressure in the control cham ber is reduced by condensation. T h e u p ward force then exceeds the downward force and the disc valve opens.
40 seconds inspection time — that's all it takes for a SARCO TD Steam Trap J u s t b a c k off t h e c a p of a Sarco T D . Lift o u t its single m o v i n g p a r t , t h e stainless steel disc. W i p e it off, a n d d r o p it b a c k . N o a d j u s t m e n t is ever r e q u i r e d , at a n y l o a d or a n y p r e s s u r e in its r a n g e — from 10 t h r o u g h 600 psi.
This 3-part Sarco TD Steam Trap has only one moving part—the hardened, polished stainless steel disc.
No other trap uses t h e velocity of the fluid to operate the valve or uses the recom pression of the flowing fluid to trap t h e valve closed and to hold it closed. When it closes, it closes tightly — no "operating steam" leaks out.
T h e T D o p e r a t e s in a n y position, w o n ' t b l o w s t e a m a t a n y load. Small as a t e e fitting, it c a n b e installed in t i g h t places. I t s versatility a n d reliability c u t cost of b i g r e p l a c e m e n t i n v e n t o r y . W r i t e for " L i t e r a t u r e Kit 2 A " t o d a y a n d g e t latest bulletins on t h e T D S t e a m T r a p a n d o t h e r Sarco s t e a m t r a p s . R e m e m b e r t h a t Sarco can give you i m p a r t i a l a d v i c e on Production
Planned
steam
because . . .
SARCO
«OS-B Only Thermostatic
Sarco makes
all 5
types:
· Liquid Expansion · Float Thcrmn-Dynamic · Bucket
Thermostatic
C O M P A N Y , I N C . 635 Madison Ave., New York 22, Ν. Υ.
STEAM 110A
TRAPS-TEMPERATURE
CONTROLLERS
INDUSTRIAL AND ENGINEERING CHEMISTRY
trapping
· SΤ RΑ Ι Ν ΕRS · ΗΕ Α Τ Ι ΝG
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