US2759489A

US2759489A - Adjustable intrusion tube for use with whistling signalling device

Info

Publication number: US2759489A
Authority: US
Inventors: George M Schutter
Original assignee: Scully Signal Co
Current assignee: Scully Signal Co
Priority date: 1953-02-06
Filing date: 1953-02-06
Publication date: 1956-08-21
Anticipated expiration: 1973-08-21

Description

Aug. 21, 1956 ADJUSTABLE fNTRUSION TUBE FOR USE WITH WHISTLING SIGNALLING DEVICE G M. SCHUTTER 2,759,489

Filed Feb. 6, 1953 Q2111 1:; .i;;; J-.u I 3 6 42 A E 6 i ii E F .6. g

132291222302 Gena-{9e MSW,

United States Patent ADJUSTABLE INTRUSION TUBE FOR USE WITH WHISTLING SIGNALLING DEVICE George M. S'chutter, West Newton, Mass., assignor to Seully Signal Company, Cambridge, Mass., a corporation of Massachusetts Application February 6, 1953, Serial No. 335,464

4 Claims. (Cl. 137-558) This invention relates to audible signalling devices of the type used in connection with the filling of tanks to indicate that filling is proceeding properly and to give a, signal when the liquid level in the tank has risen to a predetermined desired level.

In particular, the invention relates to an improved intrusion tube which is associated with the signalling device and which depends into the tank. A signalling device with which this invention is especially useful is shown in the patent to Mathey, Serial No. 2,135,522, granted November 8, 1938, for Liquid Level Indicator. The disclosure herein shows a signalling device of the same type as that shown in the aforesaid Mathey patent and having attached thereto an improved type of adjustable intrusion tube.

One of the objects of the present invention is to facilitate the installation of the signalling device in a tank. The length of the intrusion tube is determinative of the time when the whistling sound will be cut off or altered to advise the operator that a certain liquid level has been reached.

It is customary to use an intrusion tube long enough to give a signal to the operator when the tank has a remaining capacity of, say, fifteen gallons. If this signal is to be given in a conventional 275 gallon tank installed in vertical position, the intrusion tube must necessarily be longer than the tube that would be used when the tank is installed in horizontal position. Similarly, if the signal is to be given at other remaining capacities, then, of course, the length of the intrusion tube would have to be correspondingly altered.

Therefore, because of the varying lengths of intrusion tubes required for diiferent installations, it has been customary for the manufacturer of these signals to furnish the signalling unit equipped with an intrusion tube long enough to function properly under the maximum conditions that will be met, While an intrusion tube of this maximum length may be acceptable for some installations, it will not be acceptable for many others. Accordingly, it is necessary for the installer to consider the length of intrusion tube required at each installation and cut the intrusion tube with a hack saw or otherwise to the length required to meet the particular conditions.

In addition to the time consuming requirement of physically cutting the intrusion tube, it oftens happens that the installer incorrectly estimates the length of the intrusion tube required with the result that he cuts the tube too long or too short. If cut too long, the unit must be removed, the tube cut again to the proper length, and then reinstalled. If cut too short, it is necessary to install another complete unit, cutting the tube in the second case to the proper length as the too short intrusion tube of the first unit obviously can not be lengthened to meet the requirements.

With these conditions in mind which have persisted for many years without correction, although the need has been present, I have constructed an intrusion tube in which the length may be varied at will without in any ice 2. way afiecting, the operating characteristics of the device. That is to say, the sound characteristic of the whistle produced as the. displaced gas flows through the intrusion tube and whistle to the vent pipe will not be aifected, and similarly after the rising liquid has trapped the lower end of the intrusion tube gas may continue to escape thereafter through the fixed by-pass in the upper part of the intrusion tube without interference regardless of the adjusted length of the tube. In other WOrdS,, the intrusion tube of the present invention while adjustable in length will function the same as the heretofore supplied one piece intrusion tube specifically cut to the length required.

A further object of the invention is the provision of a whistle unit that will be of constant weight regardless, of they length of the intrusion tube. A constant weight unit will provide better Whistling characteristics as the relief pressure. remains constant.

These and other objects of the invention will become more apparent as the description proceeds with the aid of the accompanying drawings, in which:

Fig. 1 shows the signalling unit inserted in normal position in a tank with the adjustable intrusion tube extended its full length.

Fig. 2 is the same as Fig, 1 except that the intrusion tube has been shortened somewhat.

Fig. 3 is the same as Figs. 1 and 2 except that the intrusion tube has been reduced to minimum length.

Fig. 4 is a section on the line 44 of Fig. 1.

Fig. 5 is a section on the line 5-5 of Fig. 2.

Fig. 6 is a view of the intrusion tube looking from the right of Fig. 2.

The casing and whistle shown herein is old and no claim in made to this part of the disclosure. The invention resides in the construction of the intrusion tube and its relationship to the other parts of the signalling device, and of which further explanation will now be made.

As shown in the drawings, the signalling unit consists of a casing 2 threaded at its upper end internally at 4 for connection with a conventional vent pipe. The casing is threaded at its lower end at, 6 by means of which it is placed in engagement with the threads 8 in the top of the tank 10.

The casing has a circular seat 12 on which rests a ball shaped valve 14 usually made of type metal and which has set therein a button type whistle 16. Stops 18 and 20 act to limit the upward movement of valve 14 so that the valve cannot block the lower end of the vent pipe (not shown) which is screwed to the upper end of casing 2.

The valve and whistle have depending therefrom an intrusion tube 22 which is in series with and axially aligned with the

ports

24 and 26 of the whistle. The intrusion tube consists of two parts, an upper tubular portion 28 and. a. lower adjustable tubular portion 30. In the upper portion a short distance below the lower end of the casing is a fixed permanently open by-pass 32 which, regardless of the position of the lower adjustable. portion, is always open for the passage of gas after the lower end of the. intrusiontube has been trapped by rising liquid. In the several figures the liquid level is indicated at 34 at a point where it had risen just above the lower end of the intrusion tube.

The construction of the upper and

lower portions

28 and 30 of the instrusion tube is as follows: Near the bottom of portion 28 a small area 36 has been punched outwardly to act as a stop to the downward movement of the lower portion 30. The lower portion comprises a tube ordinarily made of sheet metal with its vertical edges overlapped as at 38 and maintaining close frictional and slidable engagement with the exterior of upper portion 28.

This tube has a vertical tunnel 40 extending most of its length and the space in the tunnel is denoted at 41. The tunnel is of such dimensions that the stop 36 fits closely within, permitting portion 30 to be moved up and down but preventing any rotation with respect to portion 28. The upper end of tunnel 40 terminates in an inwardly turned finger 4-2 having on either side V-

shaped notches

44 and 46. The bases of these notches as shown in Fig. 4 are spaced as at 48 and 50 from the exterior of portion 28 and provide free and open passages from the exterior of the tube to the tunnel interior 41. The finger 42 acts as means for limiting the descent of portion 39 with respect to portion 28 by engagement with stop 36 as shown in Fig. 1. Stop 36 may also act as means for limiting upward movement of portion 30 by engagement with the bottom end of tunnel lit as shown in Fig. 3. However, due to the length of portion 28, it will be noted that the upward movement of portion 30 is also limited by its engagement with the under side of valve 14.

The openings provided by the bulged areas 48 and 59 permit the free flow of air into the interior 41 of tunnel 4t? regardless of the vertical position of portion 30. Thus, gas will always be able to flow through by-pass 32 after the trapping of the lower end of the tube, directly when the upper end of portion 38 is below the by-pass and via tunnel 41 when the upper end of portion 30 is above bypass 32.

The fixed open by-pass 32 is an important feature because it is essential that there always be a port to permit continued venting of gas after the bottom end of the intrusion tube has been trapped. When the bottom end has been trapped by the rising liquid, the whistle ceases to sound, giving an indication to the operator that the liquid level has risen to the desired point. However, if the inflow of liquid to the tank is not immediately out ofi, then the level will continue to rise but the gas in the top of the tank instead of being compressed until valve 14 lifts from seat 12 will be permitted to continue its escape to the vent pipe through by-pass 32. By-pass 32 whose location in portion 28 is critical is so positioned that gas passing therethrough after the intrusion tube has been trapped will be sutficiently distorted on its way to the

Whistle openings

24 and 26 so that little or no sound will be produced. Thus, venting will continue after the trapping of the lower end of the intrusion tube, so long as the by-pass 32 is not interfered with.

The weight of the Whistle unit obviously will remain constant regardless of the length of the intrusion tube. This constitutes a distinct advantage over the prior constructions in which the weight varied with the length of the one piece intrusion tube. Constant weight of the unit causes the valve 14 to open at constant tank pressure and gives uniform whistling characteristics regardless of tube length.

In order to facilitate the movement of portion 30 with respect to portion 28, finger gripping elements 52 are provided at the lower end of portion 30. Elements 52 may be readily formed by a suitable die used on the metal of portion 30 before it is formed into its tubular shape.

It is my intention to cover all changes and modifications of the example of the invention herein chosen for purposes of the disclosure which do not constitute departures from the spirit and scope of the invention.

I claim:

1. An adjustable instrusion tube for use with a liquid level indicating device of the type described, said tube comprising two tubular telescoped portions open at both ends and slidable one within the other, the upper of said portions having an opening through the wall thereof and a stop extending outwardly below said opening, the lower of said portions including a longitudinal tunnel in which said stop is positioned to limit downward movement of said lower portion with respect to said upper portion and to guide said tunnel to a position over said opening when the upper end of said lower portion has been moved upwardly to a position above said opening, and a passage to the exterior of said lower portion at the upper end of said tunnel whereby when said lower portion has been moved with respect to said upper portion so that said tunnel covers said opening, gas may flow into said tunnel and thence through said opening.

2. An article of manufacture for use With an audible signalling device of the type described, comprising a whistle, a valve supporting said Whistle and a variable length intrusion tube in series with said whistle, said intru sion tube comprising a pair of telescoped tubular elements open at both ends, the upper of said elements having its upper end fixed in relation to said whistle and having an opening through the wall thereof and the lower of said elements being slidable longitudinally with respect to said fixed element and in substantially sealed engagement therewith, said lower element having means for permitting gas to flow to said opening when the upper end of said lower element has been moved to a position above said opening.

3. An. adjustable intrusion tube for use with a liquid level indicating device of the type described, said tube comprising two tubular telescoped portions open at both ends and slidable one within the other, said portions being in substantially sealed engagement with each other, the upper of said portions having an opening through the wall thereof, and the lower of said portions including an interior passage through which gas may flow from the exterior of said lower portion through said opening when the opening is covered by said lower portion.

4. An adjustable intrusion tube for use with a liquid level indicating device of the type described, said tube comprising two tubular telescoped portions open at both ends and slidable one within the other, said portions being in substantially sealed engagement with each other, the upper of said portions having an opening through the wall theerof and the lower of said portions having a raised longitudinal tunnel with an opening from said tunnel communicating with the exterior of said lower portion and means for maintaining said tunnel positioned over said opening of said upper portion whenever said portions are telescoped to the extent that the lower of said portions has covered said opening.

References Cited in the tile of this patent UNITED STATES PATENTS 915,867 Lee Mar. 23, 1909 2,135,522 Mathey Nov. 8, 1938 2,239,921 Majewski Apr. 29, 1941 2,468,667 Holbrook Apr. 26, 1949 2,531,950 Scully Nov. 28, 1950 2,638,222 Roach May 12, 1953