US2279571A - Control device for hydraulic lines - Google Patents

Description

Filed Feb. 2s, 1946 lNVENT-OR BY affon fl. /f/wg ATTORNEY Patented Apr. 14, 1942 CONTROL DEVICE FOR HYDRAULIC LINES Garold A. Kane, Minneapolis, Minn., assigner to` Northern Pump Company, Minneapolis, Minn., a corporation of Minnesota Application February 23, 1940, serial No. 320,392

14 Claims.

This invention relates to a device for controlling the ow of liquid between two lines or conduits containing liquid under pressure. Liquid is often supplied by one line under pressure to some form of apparatus actuated by said liquid or the liquid is placed under pressure in a line by some form of apparatus such as a pump. In all of such cases there is, of course, a line having a liquid therein at lower pressure to which the liquid is supplied or into which it is exhausted or discharged. It is frequently desirable to limit the pressure at which the liquid is supplied and to open means leading to the exhaust or dis- 1.

charge line when the pressure reaches a certain Point.

-It is an object of this invention to provide a simple and efficient device for controlling the flow of liquid between two lines in accordance with the pressure developed.

It is a further object of the invention to provide a simple andefficient device for controlling the ow of liquid from one line or conduit containing liquidunder pressure to aline or conduit containing liquid under lesser pressure, which device is operated by the liquid in accordance .with the pressure developed and one in which there is a negligible leakage before the main operation thereof.

It is another object of the invention to provid a device such as set forth in the preceding paragraph including a control passage having ports -l of considerable size opening thereinto, which ports are controlled by a control valve or pilot valve to cause operation of the device, said ports of considerable size insuring that there will be no clogging of the device by dirt or otherl foreign material.

It i's also an object of the invention to provide such a device as above set forth having means for varying the pressure at which it will operate.

It is still another object of the invention to provide a device `for controlling the flow of liquid from one line containing liquid under pressure to another line containing liquid under p ressure comprising a duplex device including a member having a relief passage with valves at either end thereof similarly related to the lines of high and low pressure respectively with a' control valve and passages disposed symmetrically vto said valves with adjustable means for determining the pressure at which the device will operate so t that it can be usedfor limiting the pressure on either line, said means being differentially set for the desired operating pressures.

It is further an object-of the invention to provide a device controlling the flow of liquid from one line containing liquid under `pressure to another -line containing liquid under lesser pressure comprising a member having a relief passage, a valve normally closing said passage adapted to be operated by 'the pressure of the liquid and a control valve'to which is applied the full pressure of said first mentioned line, said control valve being operated upon a predetermined pres-y sure to cause opening Aof said first mentioned valve. l

These and other objects and advantages of the invention will be fully set forth in the following description made in connection with the accompanying drawing in which like reference characters refer to similar parts throughout the several views and in which:

Fig. 1 is a vertical longitudinal section through the device taken on different planes.

vReferring to the drawing, a member'designated generally as I0 is shown, thesame having therein a passage IIla which will be referred'to as a relief passage. Said passage Ilia has valve seats Ib and Illc formed at the ends thereof and valve seat VIlibis arranged to be engaged by a valve II having a portion formed on its vend of frustoconical form adapted to closely engage seat I lib.l

SeatIIlc is engaged by a similar valve I2. Valve II has associated therewith a plunger I Ia. While plunger IIa could be connectedi'with valve II in various ways, in the embodiment of the invention illustrated it is shown as an integral part of said valve. Plunger IIa ts in and moves in a cylindrical bore or chamber Ilid formed in member I0. Valve I2 has a similar plunger I2ty associated therewith which fits in and slides in a cylindrical bore or chamber Ille. Plunger I Ia hasa cylindrical projection IIb at the side opposite valve II,

which projection is surrounded by one end of a compression coiled spring I3, the other end of which surrounds a projection Ilia on the end of a' closing member or gland I4 having cylindrical portions seated' in counterbores in the end of member I 0. Member I4 will preferably be held in place by a plurality of circumferentially spaced bolts I5 extending through the same adjacent.

. projection I8aA on a closing member or gland I8 having cylindrical portions seated in counterbores inone end ofA member I0, which member to hold said valves to their seats. A control passage IIIf is formed in member I0 preferably above passages Ind and Ille and while this pas-4 sage might be of various forms, in the embodiment of the invention illustrated it is shown as cylindrical. Passage If communicates at its ends with other bores or passages Illy and IIlh shown as of slightly larger diameter than passage IUf, thus forming shoulders and plunger disks 20 and 2| are disposed and fit respectively in passages Ig and |0h and normally engage the shoulders at the ends thereof adjacent passage I 0f. Plunge disks 20 and 2| are engaged respectively by compression coiled springs 22 and 23, the other ends of which respectively engage plunger disks 24 and 25 also fitting in and slidable in passages Ig and Ih respectively. Passages IIIg and I 8h are threaded at their outer ends and have screwed or threaded thereinto the ends of closing members or glands 26 and 21 respectively. Members 26 and 21 have shouldered portions of different diameters thereon, the ones of smallest diameters being disposed in counterbores in member Il) and having their ends engaging gaskets 28 at the bottoms of said counterbores. 'I'he shouldered portions of largest diameter engage gaskets 29 contacting the outer ends of member I0 and having portions extending at right angles thereto, one of which overlies the upper portions of members 26 and 21 respectively and the lower portions of which are seated in small recesses formed in the ends of member I0. Members 26 and 21 have reduced and exteriorly threaded outer portions on which are threaded closed cylindrical caps 30, the ends oi which engage gaskets 3| disposed between the pressure.

.the ports of passages I072, IIlk:1 and Illm to equalige the pressure on valve portions 34e, 34h and 34a. Conduit 35 will connect with the line or conduit 36 carrying the liquid with the higher Another conduit 31 is connected to member I0 and communicates with chamber Ille at the side offplunger I2a on which valve I2 is same and members 26 and 21 respectively. Members 30 preferably will have part of their periphery of angular formation so as to conveniently receive a wrench. Members 26 and 21 are centrally bored and threaded to receive threaded and headed screws 32 having reduced and pointed inner ends seated in small conical recesses in the plunger disks 24 and 25 respectively. JambA i nuts 33 are disposed on screws 32 and engage the Outer ends respectively of members 26 and 21. It will be noted as shown on the drawing that the ends of screws 32 are disposed within caps 30. A valve member designated generally as 34 i is disposed in control passage |0f, which valve may be called a pilot valve or control valve. Valve 34 comprises a Vcentral reduced rodlike portion having ends which normally as illustrated engage disks 28 and 2|. Said valve also has spaced portions or lands 34a, 34h and 34e. Land 34a controls, a port formed by a passage .lui extending from passage |0f to relief passage Illa. Another passage Illi extends from chamber Illd toward passage I 0f and has spaced passages I0y`1 and I 09'2 forming ports opening into control passage I0f. Another passage I0k extends from chamber Ille toward passage I0f and has spaced passages |I|lc1 and IIJIcl forming ports opening into control passage IIlf. Another passage IIIm has a port opening into passage I0f and extends therefrom through member III to chamber |0d at one side of plunger IIa which is the side opposite valve II. A similar passage IIin has'a port opening into .passage I0f and extends through disposed. Conduit 31 connects with another conduit or line 38 which will contain the liquid under the lesser pressure which is usually the exhaust or discharge conduit. For more convenient reference the chamber in bore Illd at the side of plunger IIa on which valve II is disposed will be referred to as chamber IIJcl1 while the chamber at the opposite side o f said plunger will be referred to as chamber |0122. The chamber at one side of plunger I2a will be referred to as IIIe1 while the chamber at the opposite side which contains spring I1 will be referred to as chamber I Dez.

The operation of the device is as follows:

Let it be assumed that liquid is supplied for any purpose in conduit 36 at considerable pressure. This liquid after passing through some apparatus or being used for some purpose is discharged into conduit 38 at a lower pressure. It is desired to limit the pressure in conduit 36 or to provide a certain differential between the two lines 36 and 38. The spring 23 will be set so that it will yield and plunger 2| will be moved upon the attainment of a predetermined pressure. This pressure, of course, can be'varied as desired by operation of the screw 32 which will compress spring 22 to give the desired pressure. With the parts in the normal position shown the high pressure from line 36 will be transmitted through pipe 35 to chamber |0111. This pressure will be transmitted from chamber IIldl to passage Illi and passages |07'1 and |07'2 to control chamber If at both sides of valve portion 34o.

The pressure will thus be transmitted through passage |0m from the chamber at the right of portion 34e to chamber |0d2. This high pressure therefore acts upon the large area at the outer side of plunger IIa and said plungerl is held in position to keep valve II closed with its end against seat IIJb. It will likewise be seen that the lower pressure from line 38 will be transmitted through conduit 31 to chamber Illel. rIfhis pressure will be transmitted through passage lk, its branches I Ille1 and 'Illlc2 and their prts to control passage `I0f at both sides of valve portion 34h. This pressure will also be transmitted from the left hand side of portion 34h through passage IIJn to chamber Ille. There is thus the same pressure at .both sides of plunger I 2a and this pressure acting against the, large outer side of said plunger will hold valve I2 in closed position with its end against seat |0c. Valve I2' is also held closed by spring I3. Springs I3 and I1 are of fairly light construction. When the predetermined pressure is reached at which it is desired to have the device operate, the pressure upon the left hand ends of portion 34e of valve 34 will cause said valve to move to the right and compress spring 23.by movement of plunger disk 2|. This causes valve portion 34e to move so that it will close the port of passage IM. When this port is closed the high pressure supplied between Avalve portions 34o and 34a is cut oil. As valve Ila to the left, thus opening valve Ii. This will permit the liquid from chamber AIlld1 to ow into relief passage a and this'liquid being at much higher pressure than the liquid in chamber Miel, valve I2 will be opened against the pressureof light spring I1 and the liquid can flow directly to the low pressure line 38. The device is used with pressures which are quite high and is often i used where the' liquid pumped is oil. It has been a problem of prior devices to prevent leakage when the pressure became high and approached the relief point. With the present construction the valve portions 34e and 34a are so arranged with ports from passages I 07'2 and Illi that the portion 36a is just opening passage |02' as passage |07? is closed by portion 36e. No leakage can thus occur until just at the point when the device operates. might possibly occur is so. small as to be negligible. In practice it has been found that valve il is held constantly and quietly at the necessary fixed distance from seat ib to maintain the desired pressure.. In some prior devices there was a tendency for this Valve to pound or vibrate. Itis pointed out that even if some liquid should leak past valve ii it will pass into .reliefpassage lila. As the leakage continues the pressure will build up in passage i 0a and when it gets to a point much above the pressure in chamber l0e1 and I 0e2 'it will move valve l2 and merely pass out into the lowv pressure line. It will be noted that the device is symmetrical and that valve portion 34a is normally centrally disposed over the port of passage i0. Portions 36h and 34o are symmetrical with relation to the ports adjacent the same. The device can thus be used to control the pressure Whether pipe 38 is the discharge or relief line or whether pipe 36 is the discharge or relief line. The device is thus a duplex device. 'Ihe springs 23 and 22 can be set so as to be compressed at different pressures. For instance. spring 23 could be set so that the device will operate to permit passage of liquid to low pressure line 38 at 1000 pounds and spring 22 could be set so as to yield upon a pressure of 400 pounds so that liquid would be relieved into line 3S if line 38 were made the high pressure line.

Attention is alsocalled to the fact that there are no small passages through which the liquid must pass in the operation of the device. The

This interval. in which any leakage ports opening into control passage i0f are all of large size and there is no, chance for dirt or foreign matter to accumulate and clog these passages, which action has occurred in devices having small passages or needle valve structures. It will also be seen that the device can be readily vented to remove all chance of-any air accumulation or any adverse action by the accumulation of air. Since the device is, as stated, symmetrical and the parts at one side are identical with the parts at the other, it is believed that it will not be necessary to describe the operation should the relief line or the discharge or exhaust line be in conduit 36.

One important feature of the device is that the full pressure from the high pressure line 36 is applied to the valve 34. In devices of the prior art the liquid has had to pass through a small opening and this throttles down the pressure. In such a case the -full pressure of the high pressure line is not applied to the valve causing` operation of the device. The present construction acts with'greater precision andthe device operates when the desired pressure is reached. The device will also operate to hold the pressure very close to the desired orpredetermined pressure.-

It is also pointed out 'that when valve portion 34o closes theportof passage |011 the pressure from the high pressure line is cut of! from passage ltd.l The same action would occur, of course, if the valve were operating the otherway when portion 3Ib would close the port of passage lok1 and cut on the pressure from chamber we. Such laction insures a positive opening of the valves Hand l2 respectively.

From the above description it will be seen that I have provided a very simple and eiiicient control device for liquids under pressure and one l which will function accurately and eiiiciently to relieve the liquid at a certain pressure. All parts are controlled by the pressure oi' the liquid and the device acts with great precision. As stated there is' no appreciable period of leakage before the device operates and there are no small passages to become clogged with dirt or other foreign material and interfere with the operation. The device is exceedingly simple and compact and can be easily and inexpensively produced. The device requires little or no attention` for maintenance. The same has been amply demonstrated in actual practice .and found to be very successful and emcient.

It will, of course, be understood that various changes may vbe made in the form, details, arrangement and proportions of the parts, without departing from the scope of applicants invention, which generally stated, consists in a device capable of carrying out the objects above set forth, in the parts and combinations of parts disclosed and defined in the appended claims.

What is claimed is:

` l. A device for controlling the flow of liquid from one line containing liquid under pressure to another line containing liquid under lower pressure comprising a chamber having openings at opposite ends, valves closing said openings;

plungers for operating said valves, a control passage, a relief port communicating with said control passage and leading to said chamber, pairs of ports leading respectively from said control passage at opposite sides oi said iirst mentioned port, the ports-- of each pair having passages leading to opposite sides of said plungers Yrespectively, a control valve in said control passage having a portion normally closing said iirst mentioned port and having portions spaced from said first mentioned portion forming chambers in said control passage with which said pairs of ports respectively communicate, ports at the other ends of said last mentioned portions respectively having passages connected to said first and second mentioned lines and yielding means at each end of said control valve holding the same in set position, said iirst mentioned portion of said control valve being normally disposed centrally over said first mentioned port and said other valve portions and ports being disposed symmetrically with respect to said first mentioned port.

2. The structure set forth inl claim 1 and means for varying the pressure at which said means will yield whereby said means may be dif-4 i'erentially adjusted to control the pressure in either line used as the high pressure line.

3. A valve for relieving hydraulic pressure from one line containing liquid under pressure to another line containing liquid under lower pressure comprising a member having a relief passage therein, a valve closing said passage, a plunger associated with said valve, a chamber adjacent said passage at'one side of said plunger to which said rst mentioned line is connected, a second chamber at the opposite'side or" said plunger, a pilot valve having spaced portions thereon, a passage leading from said reliefvpassage normally closed by one of said portions, spaced ports at either side of the other portion connected to a passage leading to said first mentioned chamber, a passage leading to said second chamber having a port disposed between said portions and thus communicating with said last mentioned passage and an adjustable yielding means holding said pilot valve in set position whereby pressure will pass from said rst mentioned line to both sides of said plunger and will l' operate on one of said portions of said pilot valve to close said passage leading to said second chamber andopen said port leading Afrom said relief passage whereby said plunger will be operated to open said first mentioned valve.

Y 4. A device for controlling the iiow of liquid from one line. containing liquid under pressure to another line containing liquid under lower` pressure comprising a member having a relief passage therein, valves at opposite ends of said passage normally closing said passage, plungers associated with said valves respectively adapted to be acted upon by pressure at opposite sides thereof tending to open or close said Valves, means connecting said rst mentioned line to both sides of one of said plungers,means for connecting said other line to both sides of said other plunger, a control passage, a passage leading from said control passage to said relief passage and a control valve in said control passage 7. The structure set forth in claim 6 and pas-y sages disposed at the remote ends of said last mentioned portions of said control valve through 4pressure comprising a member having a relief passage therein, valves closing the ends of said relief passage, a pair of chambers adjacent each of said valves respectively adapted to receive liquid under pressure for opening or closing said valves, a control chamber, a passage leading from said control chamber to said relief passage, passages leading from said control chamber and disposed equal distances at either sideof said last mentioned passage and leading to one of each of said pairs of chambers respectively, passages spaced equally from said last mentioned passages respectively and leading from said control chamber to the other chamber of each of said pairs respectively, a control Valve tting in and movable in said control chamber having a central portion normally disposed centrally over said second mentioned passage and having portions spaced having a land normally disposed centrally over and closing said last mentioned passage and having lands spaced from said land for controlling said two mentioned means respectively.

5'. The structure set forth in claim 4, yielding means at each end of said control valve and means for varying the pressure at which said means will yield.

6. A device for relieving hydraulic pressure.

from one line containing liquid under pressure to another line containing liquid under lower pressure comprising a member having a relief passage therein, valves closing the ends of said relief passage, a pair of chambers adjacent each of said valves adapted to receive liquid under pressure for opening or closing said valves, a control chamber, a passage leading iromsaid control chamber to said relief passage, passages leading from said control chamber at each side of saici last mentioned passage to one of the chambers of each of said pairs respectively, passages leading from said control chamber spaced from said last mentioned passages respectively and leading to the other chambers of said pairs respectively and a control valve in said control chamber having a central portion controlling said second mentioned passage and having portions spaced therefrom for controlling said two last mentioned two v sets of passages, said control valve being conequal distances therefrom for controlling said last two mentioned sets of passages and means for applying the pressures of said lines respectively to said control valve at the remote endsof said last mentioned portions thereof and yielding means engaging the ends of said control valve, said passages from said control chamber being arranged symmetrically with respect to the center of said passage leading from said control passage to said'relief passage. i Y

l0. A device for relieving hydraulic pressure from one line containing liquid under pressure to another line containing liquid under lower pressure comprising a member having a relief passage therein, valves closing' opposite ends of said passage, a pair of chambers adjacent each of said valves adapted to receive liquid under pressure for opening or closing said valves, plungers in said chambers connected to said valves, a controly chamber, a passage leading from said control chamber to said relief passage, passages leading and a control valve in said control chamber havstructed and arranged to be operated upon the v liquid in said first mentioned line.

ing a central portion controlling said second mentioned passage and having portions spaced therefrom for controlling said two last mentioned sets of passages, said two last mentioned sets of pas sagesA being symmetrically disposed at either side of and with respect to said second mentioned passage and said portions of said control valve being 'disposed symmetrically with respect to said centro] portion, said control valve being construct-,ed and arranged to be operated upon the attainment of a'predetermined pressure of said liquid in said first mentioned line. l

11.A device for controlling the flow of liquid from one line containing liquid under pressure to another line containing liquid under lower pressure comprising a member having a relief passage therein, a valve adapted to Y close said passage, a bore-in said member, a plunger connected to said valve movable in said bore and forming chambers therein at .Opposite sides of said plunger, a passage leading from the cham- Abers at the side of said plunger adjacent said valve to said .iirst mentioned line, a control passage in said member, a control member movable therein having spaced lands, yielding means re sf'sting movement of said control member in one direction, a passage leading from said last men tioned chamber and having branches with ports at either side of one of said lands in the normal position of said control member, a passage leading from said other chamber and having a. port dis` posed between said lands in the normal position er pressure comprising a member having a relief of said control member and a passage leading to pressure comprising a member having a relief passage therein, a pair of valves controlling the admission .of liquid to said passage, plungers associated with said valves respectively having chambers at either side thereof and adapted to be moved by pressure of said liquid, passages connesting saidl lines respectively with one of the chambers of each ofsaid plungers, a control passage spaced from said chambers. a passage leading from said relief passage and having a port communicating with said control passage, a control member in said control passage having a central land disposed centrally over said port in the normal position of said control member, yielding means resisting movement of said control member in oppositer directions and passages leading from each of said chambers at opposite sides of said plungers respectively and having spaced ports communicating with said control passages at each side of said rst mentioned port, said control member having lands spaced from said first mentioned land for con'- trolling said last mentioned ports, said -last mentioned ports being disposed symmetrically with relation to said first mentioned port and at opposite sides thereof.

13. A device for controlling the flow of liquid from one line containing liquid under pressure to another line containing liquid under lowpassage arrangedto be connected with said secv ond mentioned line, a valve closing said relief passage, chambers adjacent said valve adapted to have liquid under pressure thereinfor clos-v ing or opening said valve, a control-passage, means for connecting said first mentioned line to both of said chambers including a passage from one of said chambers to said control passage, -a passage leadingl from said controlpassage to said relief passage, a control valve in said control passage movable upon a predetermined,

pressure of said liquid'for opening saidv last mentioned passage and closing said second mentioned passage to cause a differential pressure in said chambers for opening said valve, and a third valve closing said relief passage acted on by liquid from said second mentioned line and adapted to be opened when said iirst mentioned valve is opened.

14. A device for controlling the flow of liquid from one line containing liquid under pressure to another line containing liquid under lower pressure comprising a member having a relief passage therein adapted to be connected `to said second mentioned line, a valve closing said relief passage, a plunger associated with said valve adapted to be operated on by pressure at opposite sides to close or.open said valve, a control passage, ports having passages within said mem--` ber leading from said control passage to said relief passage and to opposite sides of said plunger respectively and a control valve in said control passage movable by liquid under pressure in -said rst mentioned line at a certain point and comprising spaced lands tting said control passage to open said port leading to said relief passage and to close a port through which pressure from said iirst mentioned line is applied to one side of said plunger to cause movement of said plunger to open said rst mentioned valve, said pressure being applied to one of said lands for moving said control valve, two of said lands of said control valve being arranged for closing and opening said ports respectively and so spaced that said port leading to said relief passage is opened just as said port leading to said one side of said plunger is closing whereby there is no appreciable period of leakage into said first mentioned port before said first mentioned valve opens to relieve the pressure.

GAROLD A. KANE.

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