US2622886A - Steam trap - Google Patents

Description

J. F. M KEE STEAM TRAP Dec. 23, 1952 3 Sheets-Sheet z Filed Feb. 1, 1950 Dec. 23, 1952 McKEE 2,622,886

} STEAM TRAP Filed Feb. /l, 1950 3 Sheets-Sheetj 4/ 62 .4 3 6 7 3 I 7 2 m {a 2 an-i INVENTOR ATTO R N EYS Patented Dec. 23, 19 2 STEAM TBA? John F. McKee, Ardmore, Pa., assignor to Yarnall- Waring Company, Philadelphia, Pa., a corporation of Pennsylvania Application February 1, 1950, Serial No. 141,827

11 Claims.

The present invention relates to condensate traps of the character particularly suited for steam traps but useful in removing the liquid phase from any mixture of a substance in liquid and vapor phase.

The purpose of the invention is to facilitate rapid removal of condensate from a system at a high leakage rate as the condensate is formed.

A further purpose is to maintain the valve closed by the vapor phase down to very low pressures.

A further purpose is to permit more positive control of the leakage rate from a steam trap while at the same time rendering the control leakage rate subject to adjustment.

A further purpose is to guide the valves as they move in a steam trap.

A further purpose is to secure a related rate of port opening of the inlet and outlet valves as the trap opens which will maintain continuous positioning control of the valves with respect to the thermal state of the fluid.

A further purpose is to pivot a valve operating lever on a fulcrum, and desirably to maintain the lever in contact with the fulcrum by a spring.

A further purpose is to increase the opening force by providing an impulse disc on the inlet valve in the path of the stream.

Further purposes appear in the specification and in the claims.

In the drawings I have chosen to illustrate a few only of the numerous embodiments in which my invention may appear, selecting the forms shown from the standpoints of convenience in illustration, satisfactory operation and clear demonstration of the principles involved.

Figure 1 is a longitudinal section through the trap of the present invention, the section being taken on the line l-l of Figure 3 and showing the trap in approximately full open position.

Figure 2 is a longitudinal section corresponding to Figure 1 and showing the trap in full closed position.

Figure 3 is a plan view of the trap of Figure 2 with the bonnet removed.

Figure 4 is an enlarged fragmentary section of Figure 3 on the line 44.

Figure 5 is a plan view of the body.

Figure 6 is a fragment corresponding to Figure 2 showing a variation.

Figure '7 is a fragmentary section corresponding to a portion of Figure 2, showing a variation.

Figure 8 is a fragmentary section corresponding to a portion of Figure 2 showing a further variation.

Figure 9 is a section on the line 9-9 of Figure 8.

Figure 10 is a fragmentary elevation of a variant form of pivot.

Figure 11 is a top plan of Figure 10.

Figure 12 is a section of Figure 11 on the line l2--l2.

In the drawings like numerals refer to like parts.

Describing in illustration but not in limitation I and referring to the drawings:

My U. s. Patent 2,328,986, granted September '7, 1943 for Steam Trap illustrates in Figure 1 a trap having inlet and outlet valves mounted together and pivoted as the trap operates. The present invention is a further development of a trap of this character which is particularly intended for systems having moderate or high condensate leakage rates:

In my patent above referred to, reliance is placed upon the inherent operating characteristics of the trap to prevent complete closure of the inlet valve. In accordance with the present invention the pivoted lever on which the valves operate encounters a stop in closed position and the inlet and outlet valves are positioned so that neither is closed when the lever encounters the stop. Both the inlet and outlet valves are desirably adjustably mounted on the lever, and the adjustment is such that both valves are open when the trap approaches nearest to closing.

The inlet valve is desirably of such a developed form as to maintain a predetermined rate of port opening of the inlet to the outlet port opening which will provide the continuous valve response to the thermal properties of the fluid. Although the ideal form is bulbous as shown in Figure '7, a cone shaped inlet valve with accurately controlled angle has been found to result in acceptable control performance and is preferred for its simplicity and lower manufacturing cost.

In its preferred form, the outlet valve is a flat disc but this may be similar in form to the inlet valve provided the forms are such that the ratio of opening of the two valves maintains control relations.

The inlet valve is located farther from the fulcrum than the outlet valve, the cone partially filling the inlet port so that the ratio of inlet port opening to outlet port opening remains at same ratios (such as 2 to l) as the valves open and close.

The lever is guided at the end remote from the fulcrum so that it always travels through the same course in opening and closing.

In order to simplify the pivoting of the lever and reduce friction a knife edge is provided and the lever is held on the knife edge by a spring.

An alternate form of pivot is provided.

The trap comprises a body 29, a valve plate 25 a bonnet 22, a lever 23, an inlet valve 24 and an outlet valve 25.

The body has an inlet connection 25 adapted to receive a suitably threaded pipe, an inlet chamber 21 and an inlet port 28. On the opposite side of a partition wall the body also has an outlet port 3|, an outlet chamber 32 and an outlet connection 33 adapted to be threaded to a suitable pipe. The body has threaded bolt holes 34 at intervals for interconnection with the valve plate and bonnet.

The valve plate 2| is sealed to the body by a gasket 35 suitably of metal such as copper which engages around each valve port and separates the valve ports from one another. The valve plate 2| has an inlet valve seat 36 side by side with respect to an outlet valve seat 37. The two valve seats surround valve seat openings 38 and 40 respectively in line with inlet port 23 and outlet port 3| respectively.

The inlet valve seat 36 is provided with a conical shoulder parallel to the inlet valve side wall as later explained. The outlet valve seat is annularly conically outwardly dished at 4| to produce a clearly defined but slightly rounded edge of the valve seat for adjustment purposes and minimize deposit of dirt on the seat. The rounding of the edge aids in smooth flow of fluids.

The bonnet 22 is sealed to the valve plate by a gasket 42, suitably a metallic gasket such as copper. The bonnet is internally recessed at 43 to provide a control chamber for operation of the valves.

The lever 23 has at one end a fulcrum recess 44 which engages over a knife edge fulcrum 45 secured to the valve plate 2|. The fulcrum has lugs 46 extending on either side of the lever, and provided with openings 41 on the axis of the knife edge which receive the ends of a fulcrum locking spring 43 which has loops 5!) at each end and an intermediate hold-down portion 5! which engages in a slot 52 at the top of the lever (see particularly Figure 4). The spring tends to hold the lever against the knife edge but does not interfere with the swinging of the lever as the spring is pivoted on the axis of the lever and therefore does not act on a lever arm tending to swing the lever.

Although a spring of the type of that shown in Figures 1, 2, 3 and 4 may be used, I show in Figures 8 and 9 an alternate type of spring 48 which engages in the openings 41 in the fulcrum lugs and has a heart-shaped central downwardly directed bend 5| which engages in the slot 52 in the valve lever 23.

At the outer end the lever has stop-engaging abutments 53 at the side toward the valve plate which in lower position engage a stop surface 54 on the valve plate. The abutments 53 are separated by a guiding slot 55 which rides a guide pin 56 supported on the valve plate and extending parallel to the valve axis. This pin and slot relationship serves to guide the outer end of the lever. It will be understood that the selection as to whether the pin is on one member and the slot on the other member or vice versa is a matter of choice.

The lever supports in line with the inlet valve seat a conical plug type inlet valve 24 which remains inside the valve seat to some extent in both open and closed (as nearly as the valve does close) position, the open position being limited by the impingement of an abutment 5'! on the outer end of the lever against a stop 53 on the inside of the bonnet.

The inlet valve 24 is mounted on a threaded shank 60 which is adjustably threaded through the lever 23, manipulated by a screwdriver slot 61 and locked by a locknut 62.

The outlet valve 25 is a disc remaining at all times in the control chamber 43 and supported adjustably from the lever 23 by a threaded shank 53 adjustably threaded through the lever, adjusted by a screw driver slot (54 at the upper end and locked by a nut 65. It will be evident that the two valves are operating on different moment arms, the inlet valve being on the longer moment arm more remote from the fulcrum and the outlet valve being on the shorter moment arm, being near the fulcrum. The plug character of the inlet valve assures that the inlet valve will maintain approximately the same ratio of port opening to the outlet valve as the two valves open, providing the proper curvature or taper is employed on the inlet valve. For moment arms of inch for the outlet valve and 2% inch for the inlet valve, it has been found that the correct conical valve taper to maintain approximately the same ratio between the inlet and outlet valve openings should be from 16 to 22 degrees on the tapered conical surface 66 with respect to the axis, preferably 18 to 20 degrees. With variation in the moment arms the angle will vary in proportion. The maintenance of this angle prevents the chamber pressure from increasing excessively and thus minimizes throttling effects which would interfere with proper trap operation.

In Figure 7 the cone surface (38 is bulbous or convex and gives a more accurately constant relation between the inlet and outlet ports as the valve opens. The bulbous surface should ex tend about half way between the hemisphere having the diameter of the inlet port and the .iords from the sides to the bottom of the valve for the particular moment arms shown, and should be proportionately changed for other moment arms.

The preferable relationship between inlet valve opening area and outlet valve opening area, is approximately 2 to 1. This varies somewhat with different degrees of valve opening to compensate for the variations in pressure on the control surfaces with changing flow conditions for different degrees of valve lift.

The characteristics of the flow through the throttled valve orifices and the ratio of movement of the valves permits effective operation of the trap from the upper pressure limits down to very low pressures without change in adjustment.

In the prior art, devices of this character when adjusted for proper operation at the upper limit of the pressure range have commonly failed to maintain a closed valve condition on vapor at inlet pressures below 15 pounds per Square inch gage. With the cone and disc valves of the present invention, it is possible to keep the valve closed (as far as it will close) practically down to atmospheric pressures on vapor and to obtain good operation at high pressure for the same setting.

The bonnet is held in place by suitable bolts 51 passing through the bonnet and through holes 68 in the valve plate, into the threaded bolt holes 34. The bonnet is readily removable to permit adjustment of the valve.

In operation, the valves are screwed up close to the lever, and the lever is placed over the knife edge with the fulcrum notch engaging the knife edge. The spring is then snapped into the holes 45 at the end of the fulcrum to hold the lever in position on the fulcrum. Suitable adjusting gages are placed between each valve and each valve seat, preferably in the form of adjustment shims, and the adjustments are screwed down until they touch the shims and indicate that adequate spacing is provided between each valve and its valve seat in closed position in each case. When the valves are in this position, the lever abutment 53 will engage stop 54 in the position of Figure 2 with the shims placed between each valve and its valve seat. The lever is then raised and the shims removed. The lock nuts 62 and 65 are then tightened. The lever is then in position to move guided by the guide 56. The bonnet is then tightened in place, with the gasket interposed between the valve plate and. the bonnet.

In the preferred adjustment the valve when closed will maintain a ratio of 2 to 1 between the inlet and the outlet valve opening. Due to the slope of the cone, which with the moment arms as described will be at an angle of 16 to 22 degrees and preferably 18 to 22 degrees to the cone axis, the opening of the inlet valve should remain approximately twice the opening of the outlet valve as the valves open. This relationship prevents the chamber pressure from building up too fast and prevents diiliculty due to throttling.

The trap when connected to a condensate line of a steam system, is operated by the change in pressure between the inlet and outlet orifices in series as effected by the change in phase or the change of state of the flow medium, either prior to reaching the orifices or during passage through the orifices or as back pressure after leaving the orifices, such changes being effected by heat content, pressure or temperature of the flow medium, by difference in phase or state of the flow medium and by variant back pressure. The intermediate pressure in the control chamber inside the bonnet controls the discharge.

The conditions determining flow of condensate through the control chamber to discharge, as distinguished from mere leakage through the constantly open inlet and outlet valves in the position of Figure 2, are that pressure upon the inlet valve from the inlet side plus back pressure on the outlet side of the outlet valve tend to lift the valve lever, and when the valves open these overcome control chamber pressure from the control chamber side of the inlet valve plus control chamber pressure upon the outlet valve. As soon as the forces tending to open exceed the forces tending to close, the inlet valve is opened and opens the outlet valve so that flow of condensate occurs through the control chamber and this flow is continued until increasing temperature and vapor pressure of the condensate causes the force acting upon the valve lever from within the control chamber to overcome the effect of the inlet pressure and of the back pressure and force the valve lever toward closed position. A ood deal of the time the valve remains in a fully open position or a position nearly closed, but the valves never fully close, the nearest approach to closing being that shown in Figure 2. While the valves have been shown as round they can of course be of any conceivable cross sectional shape. a

The shape of the outlet valve seat and the conical recess around it assure a clearly defined slightly rounded edge for adjustment at the outlet, prevent trouble from accumulation of dirt at the outlet and provide favorable conditions for hydraulic flow through the outlet. The de sign of this port in conjunction with the form of the inlet port and the maintenance of the ratio of opening between inlet and outlet ports all contribute to effective functioning of the trap down to very low inlet pressure without need to change the adjustment.

In some cases the opening forces acting on the valves are not adequate to provide full valve lift up to the maximum capacity of the ports. In such instances it is desirable to provide an impulse disc HI at the upper end of the cone of the conical valve as shown in Figure 6. The impulse disc defiects the inlet stream and oifers an additional opening force beyond that due to the pressure differential. As shown, the impulse disc is located in the path of the inlet stream beyond the inlet valve seat on the control chamber side, and simply consists of a flange or washer positioned near the top of the valve. The form of Figure 6 operates like that of Figures 1 to 5 except that the impulse disc increases the opening force.

In some cases it is preferable to use a pin pivot rather than a knife edge as shown in Figures 10, l1 and 12, the valve lever 23' has a hinge opening ll which receives a hinge pin 12 held in clamp jaws T3 of a pivot support 14 having lugs 15 which straddle the lever 23. The jaws are tightened to grip the ends of the pin by clamp screws 16, desirably threaded through into the valve plate. The pivot support is secured to the top of the valve plate as by welding.

In view of my invention and disclosure, variations and modifications to meet individual whim or particular need will doubtless become evident to others skilled in the art, to obtain all or part of the benefits of my invention without copying the structure shown, and I, therefore, claim all such insofar as they fall within the reasonable spirit and scope of my claims.

Having thus described my invention what I claim as new and desire to secure by Letters Patent is:

-1. In a steam trap, walls forming a control chamber, inlet and outlet valve seats arranged side by side in the wall leading into the control chamber, a fulcrum in the control chamber at one side of thevalve seats, a lever pivoted on an established axis on the fulcrum in the control chamber and extending across the valve seats, a stop in the control chamber engaging the lever adjacent the end remote from the fulcrum, and valves on the lever independent of the stop cooperating with the valve seats and only partially closed when the lever engages the stop.

2. In a steam trap, walls forming a control chamber, inlet and outlet valve seats arranged side by side in the wall leading into the control chamber, a fulcrum in the control chamber at one side of the valve seats, a lever pivoted on an established axis on the fulcrum in the control chamber and extending across the valve seats, a stop in the control chamber engaging the lever adjacent the end remote from the fulcrum, and valves adjustably mounted on the lever independent of the stop cooperating with the respective valve seats, and only partially closed when the lever engages the stop.

3. In a steam trap, walls forming a control chamber, inlet and outlet valve seats arranged side by side in the wall leading into the control chamber, a fulcrum in the control chamber at one side of the valve seats, a lever pivotally mounted in an established axis on the fulcrum, in the control chamber, extending across the valve seats, a cooperating pin and slot guide for the lever at the end remote from the fulcrum, valves on the lever cooperating with the respective valve seats and only partially closed when the lever is in closed position and a stop independent of the valves engaging the lever and preventing the valves from fully closing.

4. In a steam trap, walls forming a control chamber, a fulcrum in the control chamber, inlet and. outlet valve seats side by side on one side of the fulcrum, the outlet valve seat adjoining the fulcrum, a lever pivoted on the fulcrum on an established axis and extending across the valve seats, a stop engaging the end of the lever remote from the fulcrum, a disc valve in the chamber adjustably mounted on the lever cooperating with the outlet valve seat and a converging plug valve independent of the stop adjustably mounted on the lever cooperating with the inlet valve seat and in the position approaching closing extending through the inlet valve seat, and inlet and outlet valves being only partially closed when the lever engages the stop.

5. In a steam trap, walls forming a control chamber, inlet and outlet valve seats arranged side by side in the wall leading into the chamber, a fulcrum adjoining the valve seat at the side remote from the inlet valve seat, a lever pivoted on the fulcrum on an established axis and extending over the inlet and outlet valve seats, a 1

spring urging the lever against the fulcrum, a stop limiting closing motion of the lever and inlet and outlet valves independent of the stop cooperatingwith the respective seats and adjusta'bly mounted on the lever.

6. A steam trap according to claim 5, in which the fulcrum comprises a pivot support, clamps on either side of the pivot support, and a pivot pin extending across the pivot support and held in the clamps, the lever being pivoted on the pivot pin.

'7. In a steam trap, walls forming a control chamber, inlet and outlet valve seats arranged side by side in the wall leading into the chamber, a valve lever extending across the seats, and fulcrumed at one end of the control chamber, an inlet plug valve at the end remote from the fulcrum and mounted on the lever, and in all positions extending through the inlet valve seat, and an outlet disc valve on the lever cooperat- 8 ing with the outlet valve seat, the inlet plug valve having a cross section decreasing in the direction away from the lever and the ratio of the opening of the inlet valve to the opening of the outlet valve remaining approximately the same in the various positions of the valves.

'8. A steam trap according to claim 7, in which the contour of the sides of the inlet plug valve is bulbous.

9. In a steam trap, walls forming a control chamber, inlet and outlet valve seats side by side at one side of the control chamber, the outlet valve seat having a conical recess surrounding said valve seat in the control chamber, a lever fulcrumed at the side of the outlet valve seat remote from the inlet valve seat in the control chamber, a plug valve on the lever cooperating with the inlet valve seat and a disc valve on the lever cooperating with the outlet valve seat.

10. In a steam trap, walls forming a control chamber, inlet and outlet valve seats on the same side of the control chamber, a lever fulcrumed in the control chamber and extending across the valve seats, an outlet valve on the lever cooperating with the outlet valve seat, an inlet plug valve on the lever cooperating with the inlet valve seat and an impulse disc around the edge of the inlet plug valve adjoining the lever.

11. In a steam trap, walls forming a control chamber, inlet and outlet valve seats on the same side of the control chamber, a fulcrum in the control chamber on the side of the outlet valve seat remote from the inlet valve seat, a lever in the control chamber extending across the valve seat and pivoted on the fulcrum, an outlet disc valve on the lever cooperating with the outlet valve seat and an inlet plug valve on the lever cooperating with the inlet valve seat and extending through the inlet valve seat in all operative positions of the valve, the cone taper of the inlet plug Valve with respect to its axis being between 16 and 22 degrees for an outlet valve lever air of inch and an inlet valve lever arm of 2%, inches, and being proportionately tapered for other lever arms to maintain substantially the same ratio between the inlet valve opening and the outlet valve opening for any position of the valves.

JOHN F. McKEE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 620,766 Goransson Mar. '7, 1899 753,999 Mosher Mar. 8, 1904 2,038,013 Temple Apr. 21, 1936 2,328,986 McKee Sept. 7, 1943

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