US1651971A

US1651971A - Tank vent

Info

Publication number: US1651971A
Authority: US
Inventors: Paul S Shield
Original assignee: Individual
Current assignee: Individual
Priority date: 1924-03-07
Filing date: 1924-03-07
Publication date: 1927-12-06
Anticipated expiration: 1944-12-06

Description

P. S. SHIELD Dec. s, 1,927'. 1,651,971'A TANK VENT Filed March 7. 1924 3 w8. 11n/Emol?A Patented Dec. 6, 1927.

'UNiTED s-Txrns.v

1,651,971 PATENT' OFFICE.

PAUL S. SHIELD, OF CINCINNATI, OHIO, ASSIGrNOR T AUGUSTINE DAVIS, JR., OE;V Y COVINGTON, KENTUCKY.

TANK VENT.

Application led March 7, 1924. Serial No. 697,430.

` The invention relates to` vvalved tankvents for relief ,of positive and negative pressure in the tank. It isV necessary in a vent for use on gasoline containers, or eX- ample, that the vent have at least twofunctions, one to relieve internal pressure whenever it is developed, as for, instance fron'r the heating of the contents due to exposure tothe sun, the other to provide for the ad;

mission of air when the contents are being drawn off, and with regard tothe latter function, in particular', thc vent should have arsuiiicient capacity to prevent any retard ing of the flow of the liquid through the dis charge line, which it may be noted is an objection applying to most or' the tank wagon vents now on the market. This latter requirement involves not only Vthe provision of sulicient area in the air passages, but it also requiresthat the valves themselves be osuch character'as to reduce to a minimum the partial vacuum necessary to open the vacuum relief. The purpose of the present inventionis to provide a vent, which among other advantages, satisr'iesv these requirements and is of a simple construction.

In the accompanying.drawings forming apart hereof; r Y

F ig. 1 is a central vertical section through a vent embodying the invention, the valve' being shown seated in ulllines and raised, as i by internal pressure, in dotted lines; and Y f F ig. 2 is a horizontalcross-section onk the line 2-2of Fig. 1. e

The vent comprises a `body 1,'which may be Vcylindrical inl form, having a. screwthreaded stem- Ql at its lower end for connection with a tank. A central longitudinal passage 3 extends ythrough the stem 2, and within the body part, and widens above into a number of counterbores or

progressive enlargements

4, 5, and 6. The chamberY 4. is

ar valve` chamber containing aV vertically' movable kvalve member 7, whichnormally rests upon avalve seat 8. Air passages 9 extend from the valve chamber enlargement downwardlyA and outwardly through the wall of-the body, placingthe

region

4, 5 in free communication with the atmosphere.`

The construction of vthe vent is such that there may be any desiredV number of rthese passageshaving anample total keiective area comparable with'the area of thepassage 3.

- vent for vacuum relief.

through the valve member 7, the valve member-.being slidableupward'on the stem, the pistonremaining stationary, as indicated by the dotted lines of Fig. l. A collar 13 on the piston stem,l below the valve, forms a one-r way connection venabling the valvek to be lifted bythe piston. when the latter rises. The top of the chamber 6 is shown tightly closed by a screwcap 14.' The chamber` 6 will be termed a closed chamber, since it is cut oli from the pressure of the atmosphere outside the tank, but a passage is provided which `'maintains communication between this chamber and the air space in the etop` of thetank. In the drawing this passage is simply and'advantageously contrived by making the stem l2 hollow throughout its length, the upper end of the passage 15 thus provided opening into the chamber 6 above the piston and the lower. end opening into the passage 3. y

VThe voperation is as follows:

If positive pressure occurs Within the tank,

such pressure liftsthe valve 7 upward along theV stem 12, and the excess pressure escapes to the atmosphere vthrough the lateral passages 9.; Vhenv Vthe pressure has been relieved the valve is automatically seated again by gravity or otherwise. t may be noted that there is no tendency for the4 piston` 10 and` its stenrl?. to rise under positive pressure in the tank, because the pressure is communicated through the passage 15 to the chamtop area of the piston. In case of partial vacuum, thatis to sayfr reduced pressure within the tank, the valve is moved in the saine direction as under positive pressure. This is effected through the chamber 6, then acting as anegative pressure chamber, and the pis- -ber 6 and acts downwardly uponthe large ton 10, overcoming the pressure of the at'-` mosphere, whichthen tends to hold the valve to its sea t, the area of the piston 10y being so muchlarger than the area ofthe-valve member, however, that it requires only slight reductioninpressure in the tank toopen the 7, onceliftedby the piston 10., remains lifted The valve membery as long as the negative. pressure condition exists, owing to the 'act that the inrush of air to the tank past the lower end of the passage l5 maintains or augments the vacuum etliect in the chamber 6. It may be noted that the base or the piston chamber forms a close-littingr seit for the bottom ot the piston, so that even atter some slight wear on the sides ot the piston has taken place the `initial vacuum necessary to start the piston upward is developed against a tight joint.

lhen the` piston is raised in response to negative pressure, thereby opening the valve, the chamber (l remains closed or substantially closed to diiect communication with the atmosphere. This results :troni the lit of the piston in the c-yliiulrical wall ot the chamber 6, any slight leakage around the piston being inconseqneiitial, and 'trom the tact that the connection between the passage 15 and the chamber (l above the piston remains unbroken. The suction o't the air rushing;r into the takn past the open lower end ot' the passage l5. which is extended downward a substantial `distance below the valve, serves to maintain or prolong the vacuum ctlect in the chamber (i to insure wide and sustained opening of the valve permitting: tree entrance of air in order that drawinor olli ot liquid from the tank shall not be retarded, insuring also that the valve will not close prematurely `bcifore normal pressure in the tank has been sull'iciently restored, and in general insuring that? the valve will act promptly and elliciently at all times and under all conditions callingl for negative pressure relief.

This concludes a `description ol the best 'form ol"` the invention now known to me. I wish it to be understood, however, that numei-ous changes in forni, proportions, ar-` rangements, details, and by way ot additions or omissions or substitution et equivalents. may be made without departing from essentials.

lVliat I claim as new is:

`l. A" tank-vent containing` a valve me1n ber adapted to vicld to positive tank prersure to permit the escape of excess pressure ronrthe tank, a chamber, and means respon sive to reduced pressure in said chamber to move said valve member in the same direction as in the case ot excess pressure, in or der to admit external pressure to the tank.

2. A tank-vent containinga valve member adapted to yield to positive tank pressure to permit the escape ot excess pressure troni the tank, a chamber, a member movable in iespense to reduced pressure in said chamber, and a shouldered stein itorniing an operative connectionbetween said member andisaid` valve member to move said valve member in thesame direction as in the case of excess pressure, in order to admit external pressure to the tank, said stem and one ot" said menibers being;1 tree :tor relative movement when the valve member yields to excess pressure.

C-l. A tank-vent containing a valve member adapted to yield to positive tank pressure to permit the escape ot excess pressure from the tank, a cliaiiiber, a member movable in response to reduced pressure in said chani bei', and a shouldered stem toi-mingl an operative connection betweeii said member and said valve member to move said valve membei' in the saine diicction as in the case o'lE excess pressure, in order to admit `external pressure to the tank, said stem being hollow` and atlori'ling` communicatiim between said chamber and the tank.

A tank-vent comprisingi a body having 'a tank connection passage, lateral vent pas "is, a valve seat between thetank connecn passage and the lateral passages, a valve member .normally res-tine against said seat and adapted to be moved therefrom by ex cess pressure in the tank, a chan'ilier beyond `the valve member in communication with the tank, a member adapted to respond to reduced pressure in said chamber. and a shouldered rod between said member and said uilve member to more said valve away from said scat when a reduced pressure condition occurs in said. chamber, the valveniember being movable relatively to said other incmbei' under excess pressure in the tank.

5. A vent having' a valve seat, a valve member normally closed against said seat and tending to be held closed by the external pressure thereon whenthe pressure in the space to be vented is lowered, a. chambei' havinimT means ol communication with the said space, and means associated with such chamber and operating to move said valve member away 4rom said seat when the pressure in said chamber is lowered.

(i. A. vent having a valve scat, a` valve member normally closed against said seat and tending to be held closed by the exter nal pressure thereon when the pressure in the space to be vented islowcrcd, a chamber havinriI means oll communication with the said space, and means associated with such chamber and operatingl to move said valve member away from saidseat when the pres-` sure in said chamber is lowered, the relation between the passagrefor the admission ot air to said space and thecommunication way between said chamber and saidspace beine' such that the inrush ot air operates to maintain a vacuum etlileet in said chamber temporarily.` y y i 7. A vent having,Y a seat, a valve member normally closed against said seat and'adapt-- cdto be moved away `from said seatby ex cess pressure in the space to be vented to permit such pressure to escape, andineans tor employiingr reduction in pressure in `such space also to unseat said valve member, the

Tll

llU

movement of the valve in both cases being in the same direction. c

8. A vent having a valve for relieving both positive and negative pressures in a space to be vented, said valve member opening away from and seating toward such space so as to yield directly to positive internal pressureV in said space, and means responsive to reduction in pressure in such space-and of superior power to the external pressure acting `on said valve member, so as to unseat saidl valve member when a condition or reduced pressure occurs in said space. f

A vent having a valve member for relieving both excess and minus pressure vin the vspace to be vented, and means whereby said .valve member moved in the Vsame direction to open the vent by Virtueoif either .atmosphere canraisc said member, and an operating)` connection between. said operating member and said valve member :tor littl ing the latter.

ll. A tank vent containing a. valve seat, a valve member which closes downward againstsaid seat, a chamber above said valve member, an operating ^member associated with said chamber and adapted to be vraised when negative' pressure is-Y communicated romthe tank to said chamber,there being a commifmication from the outside atmosphere to the space beneath said operating member so that the pressure of the atmosphere can raise said member, and a hollow stein extending downward trom said operating member and radapted to litt said valve member, the

verticalv passage. through said stem com` municating at' the upper end with theinterior ot saidchamber, and the lower end of said passage communicating with the space between said valve member. p

l2. A `tank vent containing a valve seat,

aV valve member which closes downward against said seat, a chamber above said valve member, an operating member associated with said chamber and adapted to be raised when negative pressure Vis communicated trom the tank to said chamber, there being acommunication from the voutside atmosphere to the space beneath said operatingl member so that the pressure of the' atmosphere can raise said member, and a hollow stein extendingdownward from said operating member and adapted to lift. said valve member, the vertical passage through said stem communicating at the upper end with the interior of said chamber, said passage having a tubular extension at the lower end projecting a substantial distance downward below saidV valve member in order `that iiirush of air past said extensionwill operate to maintain a vacuum effect in said chamber temporarily.

18. A tank vent containing a valve seat, a valve member which closes downward .against said seat, means forming a chamber above said'valve member whereby negative pressure communicated from the interior of the tank to said` chamber causes said valve member to be lifted by atmospheric pressure, and means formingk a vertical passage through said valve member with a tubular extension projecting downward below said valve member, to maintain a vacuum effect in said chamber when said valve is lifted in response to negative pressure in the tank.

14. A tank vent containing ka valve seat, a valve member which closes downward against said seat, means forming a chamber above said valve member whereby negative pressure communicated from the interior of lthetank to said chamber causes said valve member tobe`litted by atmospheric pressure, and means forming al communication passage between said chamber and the interior of' the tank, said passage being extended downward below said valve member anid opening into the space to be vented in such manner that inrush of air past the lower kopening of said passage will operate to maintain a vacuum effect -in .said chamber tem-k porarily, said chamber remaining substantially closed'to directcommunication with Ythe atmosphere'when said valve member is lifted. PAUL S. SHIELD.