Check valve

A thermostatic valve including a housing that defines a housing inlet and a housing outlet and a valve body having an end wall and a side wall that define a valve chamber within the housing. The end wall defines an annular valve seat and a valve inlet opening encircled thereby while the side wall defines a plurality of valve outlet openings communicating with the valve chamber. Retained within the valve chamber is a resilient, annular seal encircling the valve inlet opening and a bi-metallic disc substantially parallel to the valve seat and normally spaced therefrom by a distance greater than the thickness of the annular seal. In response to a predetermined ambient temperature the bi-metallic disc deflects concavely into the valve chamber and into fluid sealing engagement wih one end of the annular seal forcing an opposite end thereof into fluid sealing engagement with the valve seat.

BACKGROUND OF THE INVENTION 
This invention relates in general to heating systems and in particular to 
two pipe steam heating systems. 
Although extensively used, thermostatially steam trapped radiator systems 
exhibit a number of perplexing disadvantages. For example, thermostatic 
steam traps are susceptible to failure and such failures are difficult to 
diagnose. Generally, faulty traps are diagnosed with relatively expensive 
infrared equipment that must make difficult distinctions between operating 
temperatures of about 190.degree. and 210.degree. F. Even after a given 
trap has been accurately diagnosed as faulty the repair thereof is a 
relatively expensive process. Another disadvantage is relatively poor 
energy efficiency resulting from the steam traps discharge of condensate 
at either steam temperature or slightly below. That factor also is 
responsible for the annoying hammering, clapping and vibration sounds 
commonly associated with such systems. Still other problems associated 
with thermostatic steam trap radiator systems stem from the restrictions 
to high temperature condensate in many municipal sewage systems. 
The object of this invention, therefore, is to provide an improved steam 
heating system that alleviates many of the problems encountered by users 
thermostatic steam traps. 
SUMMARY OF THE INVENTION 
The invention is a thermostatic valve including a housing that defines a 
housing inlet and a housing outlet and a valve body having an end wall and 
a side wall that define a valve chamber within the housing. The end wall 
defines an annular valve seat and a valve inlet opening encircled thereby 
while the side wall defines a plurality of valve outlet openings 
communicating with the valve chamber. Retained within the valve chamber is 
a resilient, annular seal encircling the valve inlet opening and a 
bi-metalic disc substantially parallel to the valve seat and normally 
spaced therefrom by a distance greater than the thickness of the annular 
seal. In response to a predetermined ambient temperature the bi-metalic 
disc deflects concavely into the valve chamber and into fluid sealing 
engagement with one end of the annular seal forcing an opposite end 
thereof into fluid sealing engagement with the valve seat. 
In a preferred embodiment, the invention includes a steam radiator having a 
radiator inlet and a radiator outlet communicating with the housing inlet, 
and a thermostatically controlled steam trap connected for communication 
with the housing outlet. The thermostatic valve supersedes the 
thermostatic steam trap thereby eliminating problems associated with its 
use. 
According to one feature of the invention, the valve's side wall is a 
cylindrical wall normal to its end wall and defining circumferentially 
spaced apart, radially directed outlet passages and the seal is a 
resilient O-ring having a thickness defined by its opposite ends and an 
outer diameter that is less than the inner diameter of the cylindrical 
side wall. This arrangement provides a thermostatic valve that is 
relatively inexpensive and extremely compact. Providing an annular space 
between the outlet passages of the cylindrical wall and the O-ring 
enhances throughput of the valve by allowing fluid flow both over and 
under the O-ring with the disc in an inactivated position. 
According to another feature of the invention, the housing comprises a 
union, and the valve body comprises an annular skirt extending outwardly 
from the cylindrical side wall and retained by the union. This featured 
valve is easily installed into the pipe union that is typically provided 
between a conventional thermostatic steam trap and the outlet of a steam 
radiator. 
According to still another feature of the invention, the bi-metallic disc 
is adapted to deflect inwardly and close the valve in response to an 
ambient temperature of between 120.degree. and 140.degree. F. Operation of 
the valve in this relatively low temperature range ensures that operation 
of the thermostatically controlled steam trap will be superseded and 
results in relatively low temperature condensate discharge that greatly 
improves the thermal efficiency of the system.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
FIG. 1 shows a conventional steam radiator 12 for a two-pipe vapor system. 
The radiator has a steam inlet 14 and a return outlet 16. Steam from a 
boiler (not shown) is carried by mains, branches and risers (not shown) to 
a number of radiators 12 distributed throughout the structure being 
heated. Typically each room of the structure has at least one associated 
radiator 12. When a central thermostat or thermostats (not shown) activate 
a release of steam from the boiler, the steam flows into the inlet 14 of 
each radiator, through each section 12a of the radiator, and through the 
outlet 16 to a steam trap 18. 
In conventional systems the thermostatically controlled trap 18 would close 
the outlet 16 to retain steam being supplied by the boiler and resulting 
in the radiation of heat from the radiator 12. Shortly after a central 
thermostat has deactivated the boiler, the trap 18 would open the outlet 
16 allowing the residual fluid content of the radiator 12 to empty into a 
return main that carries condensed water back to the boiler. However, in 
the present invention, that operation of the trap 18 is superseded by a 
thermostatically controlled valve shown in FIGS. 2 and 3. 
A union housing 20 between the radiator 12 and the trap 18 includes an 
outlet pipe 21 from the radiator 12, an externally threaded inlet pipe 22 
to the trap 18 and an internally threaded annular coupling 23. Defined by 
the pipes 21 and 22, respectively, are an inlet and an outlet of the union 
housing 20. As shown, the housing 20 retains a temperature controlled 
valve 25 that controls fluid flow between the inlet 21 and the outlet 22. 
The valve 25 includes a valve body 26 formed by an end wall 27 and a 
cylindrical side wall 28 projecting normally therefrom. Centrally defined 
in the end wall 27 is a valve inlet opening 29 while circumferentially 
spaced apart, radially directed valve outlet passages 31 are defined by 
the cylindrical side wall 28. The outer end of the cylindrical side wall 
28 defines an annular shoulder portion 30 and axially projecting rim 
portion 32. An annular retainer ring 33 is staked under the shoulder 
portion 30 and forms therewith and the rim portion 32 an annular recess 
34. Loosely retained in the annular recess 34 is the periphery of a 
bi-metalic disc 35. The disc 35 and the valve body 26 form a valve chamber 
36. Extending outwardly from the central portion of the end wall 27 is a 
hollow neck portion 41 that accommodates a central opening 42 in a disc 
skirt 43. The disc is secured, for example by solder, to the valve body 
26. An outer portion 44 of the skirt 43 extends beyond the sidewall 28 and 
is engaged in a fluid type manner between the pipes 21 and 22. 
Disposed within the valve chamber 36 is a resilient O-ring 45 formed, for 
example, of silicone. The O-ring 45 encircles the valve inlet opening 29 
and has one end 47 directly adjacent an annular valve seat 48 formed by an 
inner surface portion of the end wall 27. An opposite end 49 of the O-ring 
45 is disposed directly adjacent to the bi-metalic disc 35. As shown in 
FIG. 2, the thickness of the O-ring 45 defined by its ends 47 and 49 is 
less than the normal spacing between the valve seat 48 and the bi-metalic 
disc 35. Also the outer diameter of the O-ring 45 is slightly less than 
the inner diameter of the cylindrical side-wall 28. Thus, there exist 
between the valve inlet 29 and the valve outlets 31 flow passages between 
the O-ring 45 and, respectively, the valve seat 48, the bi-metalic disc 35 
and the inner surface of the cylindrical side wall 28. It should be 
understood that these clearances are slightly exaggerated in FIGS. 2 and 3 
for purposes of clarity. 
In response to a predetermined ambient temperature, however, the bi-metalic 
disc 35 deflects concavely into the valve chamber 36 as shown by dotted 
lines in FIG. 2. The deflected disc 35 sealingly engages the end 49 of the 
O-ring 46 and forces the opposite end 47 thereof into sealing engagement 
with the valve seat 48. Thus, fluid flow is prevented between the valve 
inlet 29 and the valve outlets 31. In response to a subsequent reduction 
in ambient temperature, the bi-metalic disc 35 returns to its original 
position and again allows fluid flow between the valve inlet 29 and the 
valve outlets 31. 
OPERATION 
When steam is supplied by a boiler to the radiator 12, the bi-metalic disc 
35 quickly reaches a predetermined activation temperature, preferably of 
about 130.degree. F., and deflects inwardly to close the valve 25. Thus, 
steam is retained by the radiator 12 resulting in radiation of heat 
therefrom. Some time after the supply of steam to the radiator 12 has 
terminated, the ambient temperature of the disc 35 will fall to a given 
return temperature, preferably of about 100.degree. F. The resultant 
return of the bi-metalic disc 35 to its undeflected position reopens the 
valve 25 allowing a discharge of the residual fluid within the radiator 
12. That fluid, primarily condensate, passes through the steam trap 18 to 
a return main (not shown). Thus, steam never reaches the trap 18 and its 
function is completely superseded by the valve 25. For that reason, the 
present invention completely eliminates the heretofore described problems 
associated with conventional thermostatically controlled steam trap 
heating systems. 
Obviously, many modifications and variations of the present invention are 
possible in light of the above teachings. It is to be understood, 
therefore, that the invention can be practiced otherwise than as 
specifically described.