Vent

Oct 8, 1935.

C. H. EHLERS

VENT

2,016,278

Filed April 12, 1934

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Patented Oct. 8, 1935

2,016,278

UNITED STATES PATENT OFFICE

2,016,278

VENT

Carl H. Ehlers, Penfield, Pa., assignor to The Atlantic Refining Company, Philadelphia, Pa., a corporation of Pennsylvania

Application April 12, 1934, Serial No. 720,301

Claims. (Cl. 220—44)

This invention relates to vent devices or safety valves for liquid receptacles and more particularly adapted for vehicle tanks employed in the transportation of liquid fuels or the like.

In order to facilitate filling and emptying receptacles of the type above referred to, there should be a vent for discharging or admitting air to relieve the pressure or vacuum which would otherwise develop. This vent should also be operative to discharge air or vapor or to admit air to compensate for any change of pressure in the receptacle due either to normal temperature changes under ordinary operating conditions or to abnormal temperature changes due, for example, to exterior fire and quenching of the fire by a water stream. The vent should further be operative normally to prevent escape of liquid in the case of partial or complete overturning of the vehicle on which the receptacle is mounted but to permit escape of liquid in the event that the vehicle catches fire resulting in the subjection of the liquid to excessive temperature with consequent pressure increase in the receptacle due to evaporation of the liquid.

An object of this invention is a simple and efficient vent device meeting the above enumerated requirements and which is of compact construction, is reliable in operation and in which the various parts are easy of access for inspection or replacement.

Other objects, novel features and advantages of this invention will become apparent from the following specification and accompanying drawing, wherein:

Fig. 1 is an axial section through a vent device embodying the invention, with the movable parts in the position normally occupied by them; and

Figs. 2 to 5 inclusive are views similar to Fig. 1, showing the parts in positions assumed under different conditions of usage.

The casing of the vent device consists of a body portion 10 provided with threads 11 by which it may be attached to a tank and with threads 12 which coact with threads on the cap 13 to attach the latter to the body 10, thus forming the complete casing. The cap 13 is provided with ports 14 and with an inwardly projecting flange 15.

The body portion 10 has a central cylindrical bore terminating at its lower end in an inwardly projecting flange 16 and is provided with a plurality of axially extending ribs 17 which guide tubular valve member 10 mounted in the body 10 to slide axially thereof, this member being of larger diameter than the interior diameter of the flange 16 so that the latter acts as a valve seat for the former. The interior diameter of the flange 15 is less than the diameter of the member 18 and also acts as a valve seat for the member 18. The member 18 is provided at its ends with inwardly extending flanges 19 and 20. A web 21 is normally 5 held against the flange 19 by means of a spring 22 interposed between the web and the flange 20. The member 18 is provided with inwardly extending ribs 23 which act as guides for the web 21.

The apertures in the web 21 are normally closed 10 by a plate 24 provided with a shank 25 extending through a central aperture in the web. A spring 26 interposed between the web and a nut 27 on the end of the shank 25 normally tends to hold the plate 24 against the web 21. 15

During drainage of the tank to which the vent device is attached, the parts assume the position shown in Fig. 2 to permit air to enter and relieve vacuum which would otherwise develop. The plate 24 is pulled down away from the web 21, 20 the spring 26 being compressed and air flows inwardly through the port 14 and downwardly through the member 18 and through the apertures in the web into the tank. Should vacuum develop in the tank by reason of cooling of its 25 contents, the vacuum will be relieved by the entrance of air in the manner just described.

Fig. 3 shows the position assumed by the parts during filling of the tank to which the vent device is attached to permit air to escape and thus 30 relieve the pressure which would otherwise develop in the tank. The member 18 is lifted against gravity, thus permitting air to flow through the central aperture in the body and through the space between the member ί 8 and the 35 inner surface of the casing 10 into the cap and then outwardly through the ports 14. Should pressure develop in the tank by reason of evaporation, the pressure will be relieved by escape of gas in the manner just described. 40

In the event of a surge of liquid in the receptacle due to stopping or starting of the vehicle by which the receptacle is carried, escape of liquid is prevented by the member 18 which is of sufficient weight normally to remain seated under 45 such conditions and the strength of the spring 22 is sufficient to keep the web seated. The member 18 may be lifted away from its seat (6 by a very heavy or abnormal surge, but will be so lifted only a very small distance and only momentarily. Re- 50 sistance of the member 18 against outward flow of liquid is so great as to permit only very little liquid to flow into the body 10 under an abnormal surge and none of such liquid would escape by way of the ports 14 but recede back into the receptacle. 85

2,016,278

Fig. 4 shows the position assumed by the various parts upon overturning of the tank to which the vent device is connected. The pressure of the liquid in the tank, together with gravity, move the member 18 against the flange 15, the spring 22 being of sufficient strength to hold the web 21 in contact with the flange f9 against the pressure exerted by the liquid. Liquid is thus prevented from flowing into the cap 13 and escaping through the ports 14. However, should excessive pressure tend to develop in the tank or receptacle by reason of abnormal evaporation due to exterior fire or any other cause, such pressure will be relieved by movement of the web against the action of the spring 22 into the position shown in Fig. 5. In this position, fluid will flow through the bottom opening in the member 18 around the periphery of the web 21 and then into the cap 13 from which it will escape through the ports 14. The web 21 may be similarly actuated with the vent device in upright position should excess pressure develop in the tank by reason of fire and the member 18 be lifted into contact with the flange 15 by reason of such excess pressure.

A single or multiple screen 28 is provided in the cap between the flange 15 and the top of the cap. This screen will effectively prevent passage of flame through the vent from the exterior of the tank into the interior thereof.

It is of course apparent that various modifications may be made in the structure above described, without in any way departing from the spirit of the invention as defined in the appended claims.