Float assisted automatic driptrap

A vertically oriented float assisted automatic driptrap mechanism having a float valve chamber defined by a body section and base is disclosed. A float is located for vertical liquid level responsive movement within the float valve chamber and reciprocates within a valve stem float guide. A diffuser is provided at the inlet of the chamber to prevent impingement of incoming fluid on the float. The valve stem guide also serves as a filter support for a filter which filters out contaminants that might interfere with the valving action of the driptrap mechanism. A valve seat having a tapered seat surface and a self-positioning valve plug movably supported by the valve stem and having a differently tapered sealing surface establish line contact sealing to ensure effective valve operation under high pressure conditions.

FIELD OF THE INVENTION 
This invention relates generally to automatic driptraps for fluid handling 
systems which respond to a predetermined level of liquid that is collected 
within a float chamber to permit float actuated automatic discharge of the 
collected liquid into a receiving line. More particularly, the present 
invention is directed to the provision of a float assisted automatic 
driptrap mechanism which is specifically designed to achieve bubble tight 
sealing within its service pressure range and for achieving efficient 
operation even when the float controlled valve mechanism thereof is 
subjected to relatively high working pressure. 
BACKGROUND OF THE INVENTION 
Historically float actuated automatic driptraps tend to be designed with 
the axis of the float in the horizontal position so that as it rises and 
falls typically with a pivotal movement in response to the liquid level 
within the float chamber, its horizontal actuating shaft applies force to 
a pivotal valve actuator lever to provide for seating and unseating forces 
of a valve element such as a valve plunger which seats against an internal 
valve seat. The sealing components of such automatic driptraps are 
typically constructed of steel and are arranged to form a metal-to-metal 
seal. The maximum working pressure of driptrap valves of this type is 
normally about 5 PSIG, and on special applications up to 25 PSIG. With the 
metal-to-metal seat design that is typically used in conventional 
driptraps, leakage is typically expected and accepted in the waste water 
treatment industry. At the higher working pressures, i.e. in the range of 
25 PSIG, conventional driptrap valve mechanisms will not operate properly 
to achieve absolute sealing capability and thus will leak a considerable 
amount. This is also considered acceptable at the present time in the 
waste water treatment industry. 
It is desirable to provide a float energized automatic driptrap mechanism 
that is capable of providing improved performance in comparison with 
existing float operated automatic driptrap devices, specifically related 
to achieving bubble tight sealing capability and providing for efficient 
and effective valve operation even when the valve is subjected to 
relatively high working pressure. 
SUMMARY OF THE INVENTION 
It is a principle object of the present invention to provide a novel float 
energized automatic driptrap mechanism having a float that is vertically 
movable within a float chamber and which achieves vertical movement of a 
valve stem and plug relative to a valve seat. 
It is another object of the present invention to provide a novel float 
energized automatic driptrap mechanism having a valve seat and valve plug 
that are arranged to establish line contact sealing when the valve plug is 
in its closed position relative to the valve seat. 
It is an even further object of the present invention to provide a novel 
vertically oriented float operated automatic driptrap mechanism having a 
lower axial guide stem and low friction stem guide assembly which permits 
the float to be efficiently responsive to liquid level within the float 
chamber. 
It is also an object of this invention to provide a novel vertically 
oriented float energized automatic driptrap assembly wherein the discharge 
opening that is controlled by the valve plug and valve spat is located 
sufficiently below the level of the float that liquid remains within the 
float chamber when the valve plug is caused to establish seating with a 
valve seat, thus preventing air or other gases from being discharged from 
the float chamber as collected liquid is being discharged therefrom. 
It is an even further object of the present invention to provide a novel 
float energized automatic driptrap assembly which ensures against the 
discharge of debris from the float chamber through the open valve and 
discharge opening in the event the automatic driptrap assembly is being 
utilized in relatively dirty liquid applications. 
It is another object of this invention to provide a novel float energized 
automatic driptrap assembly having an internal diffuser at the inlet 
thereof to ensure against impingement of incoming liquid onto the float 
where it might otherwise cause premature closure of the seat plug at high 
working pressures. 
Briefly, the various objects identified above, together with other features 
and objects which will become apparent upon a thorough understanding of 
the present invention, are realized through the provision of a float 
assisted automatic driptrap assembly that is provided with a driptrap body 
housing structure having a base and body which define respective fluid 
inlet and outlet openings. The body housing structure defines an internal 
float valve chamber within which is received a float which is vertically 
movable within the chamber responsive to the level of collected liquid 
contained therein. At the upper portion of the body housing, a diffuser is 
positioned within the float chamber and is supported by the body housing 
structure and serves to direct incoming liquid, especially at relatively 
high velocity, so that it does not impinge directly upon the float and 
thus does not influence the liquid level induced closing force to which 
the float is subjected. 
Within the base a valve seat is disposed in fixed relation with the housing 
structure and is located within an internal receptacle defined by a guide 
housing. A valve stem projects downwardly from the float and is movably 
received in guided relation by a vertically oriented guide passage of the 
guide housing. The float actuated valve stem is guided by a low friction 
bushing of the guide housing which defines the vertically oriented guide 
passage and is movable vertically relative to the valve seat. A valve plug 
is connected at the lower portion of the valve stem and includes a tapered 
lower extremity which is received in guided relation with respect to a 
tapered valve seat surface of the valve seat. Differing tapers are defined 
by tapered lower extremities of the valve plug and the tapered surface of 
the valve seat thus causing a circular line contact sealing to be 
established. 
A filter screen is arranged exteriorly of the guide housing and serves to 
filter fluid passing from the float chamber through the open valve seat 
such as when the driptrap mechanism is being utilized in relatively dirty 
fluid handling conditions.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT 
Referring now to the drawings and first to FIG. 1 a vertically oriented 
float energized automatic driptrap assembly is shown generally at 10 and 
includes a tubular body housing section 12 and base 16 which are 
maintained in sealed relation by means of circular sealing element such as 
resilient O-ring seal 20 which is received within a circular seal recess. 
The base and body are secured in assembly by means of a plurality of hex 
bolts 22 having hex nuts 24 threadedly connected at flanges thereof. The 
body 12 and base 16 may also be provided with externally accessible access 
or drain plugs 17 and 19 respectively to enable release of gases, draining 
of liquid or other servicing activities to be conducted without requiring 
the opening of the housing or removal of the driptrap apparatus from the 
inlet and discharge lines. It should be appreciated that top and bottom 
closure members could be provided for base 16 rather than the preferred 
embodiment of FIG. 1 where a cast body 12 is closed only by a bottom base 
member 16. 
The body 12 and base 16 respectively define integral bosses 26 and 28 which 
project inwardly from respective end walls 30 and 32. The bosses 26 and 28 
define internally threaded inlet and outlet openings 34 and 36 
respectively, which are adapted to receive suitable inlet and discharge 
piping for connection of the driptrap assembly into drip collection and 
discharge lines. Within the inlet opening of the inlet boss 26 is provided 
a diffuser 38 having an internal diffuser passage defined by a vertically 
oriented passage section 40 in communication with the inlet opening 34 and 
a lateral diffuser passage section 42 having laterally oriented openings 
that direct inlet fluid toward the internal wall surface 44 of the body 
housing section 12. The diffuser 38 may be connected to the boss 26 by 
threading, press fitting or by any other suitable means. A lock nut and 
washer assembly 54 is provided to secure a valve stem 56 in threaded 
assembly with the float 50 as shown in FIG. 1 and also shown in detail in 
FIG. 2. 
As shown in detail in FIG. 2 the upwardly projecting boss 28 defines a 
vertically oriented discharge passage 60 having an upper portion thereof 
internally threaded as shown at 62 for receiving an externally threaded 
seat bushing 64. The seat bushing defines a centrally located, vertically 
oriented passage 66 and also defines a tapered or conical upwardly 
directed seat recess or surface 68 against which is adapted to seat the 
tapered or conical lower external portion 70 of a valve plug 72 which is 
secured within a plug receptacle 74 of the valve stem 56 by means of a 
spring pin 76 which extends through registering apertures defined in the 
lower extremity of the valve stem. The valve plug 72 is loosely received 
within the receptacle 74 and thus is allowed some degree of lateral 
movement within the receptacle and pivotal movement with respect to the 
mounting pin 76 so as to permit the valve plug to have substantially 
omnidirectional movement for seeking optimum seating relation with respect 
to the tapered seat surface 68. Further, the conical tapers of the 
surfaces 68 and 70 may be different so as to permit circular line contact 
seating of the seat plug 72 relative to the seat surface 68. This feature 
enhances the sealing capability of the valve plug and seat at a wide range 
of sealing pressure conditions. 
The driptrap mechanism is provided with a valve guide housing 78 having an 
internal vertically oriented passage 80 within which is received a valve 
guide bushing 82 composed of a low friction material such as 
polytetrafluoroethylene such as is sold by E. I. Dupont under the 
registered trademark "Teflon". The valve stem 56 includes a large diameter 
section 84 which extends in efficient close fitting guided relation 
through a vertically oriented guide passage 85 of the Teflon bushing 82. 
The low friction character of the guide bushing 82 also enhances the 
responsiveness of float movement to liquid level changes. For the purpose 
of limiting upward movement of the float 50, the valve stem 56 is provided 
with a stop 86 in the form of a split snap ring which is received within a 
circular external groove defined by the valve stem. The stop 86 is 
oriented to contact the downwardly directed internal shoulder 88 of the 
stem guide housing 78 when the float and valve stem have moved upwardly to 
the desired maximum extent thereof. 
For assembly of the stem guide housing 78 to the upwardly projecting boss 
28, the boss defines a reduced diameter annular upper portion 90 which 
defines a circular external retainer groove 92. A set screw 94 or other 
suitable retainer extends through a threaded opening of the lower 
extremity of the guide housing as shown and is received in restraining 
relation within the groove 92. Obviously more than a single set screw may 
be utilized for securing the guide housing to the internal boss if 
desired. 
Externally, the stem guide housing 78 defines a reduced diameter section 96 
enabling a generally cylindrical filter screen to be secured externally 
thereof by upper and lower filter clamps 100 and 102. The stem guide 
housing 78 also defines a pair of opposed fluid entry ports 104 and 106 
which are positioned intermediate a centrally oriented annular recess 108 
and which permit the filter 98 to have annular standoff intermediate its 
extremities from the external wall surface of the recess 108. In the event 
a dirty fluid is being handled by the driptrap mechanism and tends to 
build up on the filter immediately opposite the entry ports 104 and 106, 
the fluid can enter the recess 108 at any portion about the periphery of 
the filter and thus flow to the inlet ports. This will minimize the 
frequency of periodic maintenance of the filter when the driptrap 
mechanism is being utilized in relatively dirty fluid handling conditions. 
OPERATION 
When the valve plug 72 is positioned by the valve stem 56 and float 50 as 
shown in FIG. 2, any fluid within the chamber 58 of the driptrap mechanism 
will be permitted to flow through the filter screen 98 and through the 
inlet ports 104 and 106 to the valve seat opening 68. The collected fluid 
will then exit through passage 66 of the seat bushing 64 and through the 
appropriate discharge line that is coupled with the internally threaded 
receptacle 36. As the fluid level within the chamber 58 descends, the 
float 50 also descends, thereby moving the valve plug 72 toward its seated 
relation with the tapered seat surface 68. At a point where significant 
liquid level exists in the chamber 58 to position the liquid gas interface 
well above the valve seat 68 to thus prevent any gas from exiting through 
the valve mechanism, the valve plug 72 will move into seated, line sealing 
contact relation with respect to the tapered seat surface 68. As mentioned 
above, the valve plug 72 has sufficient degree of lateral and pivotal 
movement relative to the valve stem that it will seek optimum seating 
relationship with respect to the tapered valve seat 68. The circular line 
contact seating relation of the valve plug relative to the valve seat, and 
the fact that the valve plug has substantially omnidirectional movement 
relative to its valve stem, ensures that the tapered sealing surface of 
the valve plug can establish optimum seating relation with the valve seat 
so as to enable the valve mechanism to establish optimum sealing even 
under a wide range of pressure conditions, including relatively high 
pressure. 
After the valve plug has become seated against the tapered valve seat 68, 
the liquid level will begin to rise within the float valve chamber 58. As 
the liquid level rises, its upwardly directed force on the float 50 
increases. When such force on float 50 exceeds the seating force of the 
valve plug against the valve seat, the valve plug will suddenly be 
unseated from the valve seat, and the float will quickly move upwardly to 
the position shown in FIG. 2 thus fully opening the driptrap valve 
mechanism for efficient discharge flow therethrough. The presence of the 
vertically oriented valve stem 56, together with the presence of the low 
friction Teflon bushing 82 provides the float with efficient 
responsiveness to liquid level. The automatic driptrap mechanism of this 
invention is therefore capable of providing improved performance in 
comparison with existing float assisted driptrap devices and is capable of 
achieving bubble tight sealing and achieving efficient operation even when 
the valve mechanism is subjected to relatively high working pressure. 
Since certain changes or modifications may be made in the disclosed 
embodiment without departing from the inventive concepts involved, it is 
the aim of the appended claims to cover all such changes and modifications 
falling within the true spirit and scope of the present invention.