US2386874A

US2386874A - Venting means

Info

Publication number: US2386874A
Application number: US543792A
Authority: US
Inventors: Irving O Miner
Original assignee: BUILDERS IRON FOUNDRY
Current assignee: BUILDERS IRON FOUNDRY
Priority date: 1940-07-10
Filing date: 1944-07-07
Publication date: 1945-10-16
Anticipated expiration: 1962-10-16

Description

Oct. 16, 1945. MINER 2,386,874-

VENTING MEANS Original Filed July 10, 1940 INVENTOR //V//V6 0. M/IVEE Patented Oct. 16, 1945 VEN TIN G MEANS Irving 0. Miner, East Providence, R. I., assignor to Builders Iron Foundry, Providence, R. I., a. corporation of Rhode Island Original application July 10, 1940, Serial No.

344,640, now Patent No. 2,357,341, dated September 5, 1944. Divided and this application July 7, 1944, Serial No. 543,792

2 Claims.

This invention relates to improvements in venting means. More especially it has to do with the venting of a chamber under a piston in a vertically disposed cylinder wherein liquid is to be maintained.

This application is a division of my original application, Serial No. 344,640, filed July 19, 1940, which became Letters Patent No. 2,357,341 on September 5, 1944.

There is shown in the appended drawing a direct-acting liquid-flow controller wherein the effective flow area is changed in accordance with the variations in the pressure causing flow to the end that the rate of flow is maintained substantially constant. The controller comprises as a pressure responsive element a cylinder with a piston therein movable on a vertical axis. This piston is subjected to liquid pressure on both its upper and lower sides, and it is highly important to insure accurate and sensitive response of the piston that nothing but liquid be in the chambers on opposite sides of the piston.

It is therefore an object of this invention to provide novel venting means for the chamber under the piston to the end that it may initially be freed of all gas and will thereafter be subject only to liquid pressure.

The best mode in which I have contemplated applying the principles of my invention is shown in the accompanying drawing but this is to be taken as merely illustrative because it is intended that the patent shall cover by suitable expression in the appended claims whatever features of patentable novelty exist in the apparatus disclosed.

In the accompanying drawing:

Fig. 1 is an elevation of a controller with its associated cylinder and piston shown in medial section and disclosing my novel venting means; and

Fig. 2 is an enlarged view of certain of the details shown in Fig.

Referring to the drawing the controller I comprises a body section l2 and a discharge section M. The inlet It to the body section is connected to a source of supply (not shown) and the outlet I8 from the discharge section is connected to a discharge line (also not shown) in which it is desired that the rate of flow shall be maintained substantially constant. Between the inlet and the outlet the controller embraces a Venturi shaped passage or othe means for efiecting a difierential of pressure in the line of flow. The rate of flow through the controller and consequently in the discharge line is regulated by varying the effective flow area of the flow passage beyond the pressure differential means. The details of the particular controller herein shown for illustrative purpose will be found shown in my aforesaid Letters Patent. Sufiice it to say, that the elfective flow area is changed by means associated with a horizontal shaft 20 which extends outside the body IZand has secured thereto a grooved pulley 22. Around this pulley is a cable 24 which forms a connection between a balance beam 26 at the top of the controller and a tubular piston rod 28 extending within a cylinder 38 at the bottom of the controller.

Thisv cylinder has a base member 30a and a cover member 30b bolted thereto. Between these two members of the cylinder is clamped the upper edge of a diaphragm 32, made of rubber or other suitable pliable material, the lower edge of which is secured to the upper edge of an upstanding skirt 34a of a piston 34. When the piston is in its uppermost position with the top edge of the skirt resting against the cover member (as indicated in dotted outline in Fig. 1) the diaphragm lies downward along the outer face of the skirt to close by its bottom edge and then across the space between the skirt and the cylinder wall, whence it extends along the inner surface of the cylinder to its clamped upper edge. As the piston moves downward the diaphragm progressively transfers from the side of the skirt to the wall of the cylinder until the piston reaches its lowermost position as seen in full lines in Fig. 1. Thus the chamber 36 above the piston is maintained separate from the chamber 38 below the piston at all times, and both chambers should be filled with liquid taken from the flow passage through the controller.

The upper chamber 36, above the piston, is connected by a pipe 31 to the inlet end l6 of the body. where the flow area is large or where the pressure is relatively high. The lower chamber 38, under the piston, is connected by a pipe 40 to the controller at a point where the flow area is small or the pressure is relatively low. Thus the liquid in the lower chamber is always below that of the upper chamber Whenever flow is taking place. To overcome this differential of pressure, the

weights

42 and 44 on the balance beam 26 may be so adjusted that the piston will be held in some intermediate position so long as the desired rate of flow is maintained. If this changes, then the resulting change in the aforesaid differential of pressure will cause the piston to move upward or downward to alter the means which change the effective flow area, thereby restoring the desired rate of flow.

It is important that both

chambers

36 and 38 on opposite sides of the piston be filled with liquid and not contain any gas as the presence of the latter affects the sensitiveness of "the pressure responsive means and may also cause inaccurate operation of this means. The upper chamber 36 may be easily vented by the usual and simple vent cock 46 screwed into the cover 30b. It is not so simple a matter, however, to insure venting of the lower chamber 38, and. so myimprovements are directed to that end. V

The piston 34 has a plate portion 34b that is in clined from its outer edge, near the bottom of the skirt, to a hub 34c at the center of the plate. Below this hub (see Fig. 2), in the lower side of the plate is a recess 3401 having separated outstanding bearing lugs 34c providing bearing surfaces for a nut 48 which is screwed onto the lower end of the piston rod 28. The latter is tubular, extends upward through a stufling box 50in the cover of the cylinder, and is'secured' to a connection block 52 to which is also attached the cable 24. This block 52 is bored to provide a passageway from the'hollow 28a of the tubular piston 28 to a relief cook 54 screwed into the block;

When the liquid is introduced to the lower chamber 38 through the pipe'40 the valve 58 in pipe '31 is closedand the upper cook 46 is open to insure that the piston will rise to its highest point. Then the cook 54 is opened, and all the air or gas in the chamber 38 Wi11,'by virtue of the inclination of the plate portion 341), the recess 34d, and ports 28?) located in the piston rod near the'top of the recess, pass into the hollow of the piston rod and escape by way of'the cock 54;

When liquid starts to come out the cock 54 is 7 closed and thus it is certain that only liquid is present in the lower chamber 38.' Liquid is next introduced to the upper'cha'mber 38 by opening valve 58 and this liquid will force all the air or gas in this chamber out through the cock 46, after which the latter is closed. Thus both chambers above and below the piston are freed of all gas or air.

Although the cylinder and piston herein shown employ a diaphragm between them, this is not an essential arrangement and my improved venting means would be just as applicable if the piston had the usual running fit with-the wall of the cylinder. The structural features of my improvements are the inclined face on the bottom of the piston, the central recess, the ports into a tubular piston rod, and the cock connected with the tubular passage of the rod outside the confines of the cylinder.

I claim:

1. Means for venting the space below a piston movable in a vertically disposed cylinder, comprising the said piston, a surface on the bottom of the piston inclined toward its axis, a recess in the said surface at said axis, separated bearing lugs depending from said recessed surface, a tubular piston rod projecting through the piston and secured thereto by a nut threaded on the rod and seating on said lugs, the said rod extending upwardthrough the cylinder having a passage leading from said recess to outside the cylinder, and means in the piston rod outside the cylinder for effecting the opening or closing of said passage.

2. Means for venting the spacebelow a piston movable in a vertically disposed cylinder comprising a piston having a bottom surface inclined toward the axis of the piston and terminating in a recess at said axis, separated bearing lugs depending from said recessed surface, a tubular piston rod connected to said piston by a nut threaded on the rod and seating on said lugs, said rod extending through the piston having ports in the wall of the rod opposite said lugs for connecting the space of the recess with a passage in the piston rod that extends to outside the cylinder, and means on the piston outside the cylinder for effecting the opening or closing of said passage.

IRVING O. MINER.