US2360894A - Liquid level control system - Google Patents

Description

0a. 24, 1944. c, D. RYAN LIQUID LEVEL CONTROL SYSTEM Filed Oct. 29, 1940 5 Sheets-Sheet 1 Oct. 24, 1944. c. D. RYAN 1 2,360,894

LIQUID LEVEL CONTROL SYSTEM Filed 001:. 29, 1940 I5 Sheets-Sheet 2 villi/ 11111111111111 Oct. 24, 1944. YAN 2,360,894

LIQUID LEVEL CONTROL SYSTEM Filed Oct. 29, 1940 3 Sheets-Sheet 5 25 21 Y 25 Fig. 8. Z4

xi i M '1 50 s :1 P 29 i L 1X:

107 j I r I F 'r- .L 1 I l h x COMMODORE 0. 0mm

Patented Oct. 24, 1944 LIQUID LEVEL CONTROL SYSTEM Commodore D. Ryan, IrosAngeles, Califi, assignor to Commercial-Controls Corporation, a corporation of Delaware Application October 29, 1940', Serial No. 363,258

13 Claims.

This invention relates to water supply systems for envelope-sealing machines, and the like; and has as a general object to simplify the construetion and operation, andreduce the cost of-such devices.

It is common practice in envelope-sealing machines to provide amoiste'ningblade adapted to contact the gummed-surfaces of envelopes to be sealed, andto feed water thereto through a thin slit in the blade. Such devices require a water supply system that will deliver'water to the-blade at a relatively exacthydrostatic head sothat the water will flow through the slit in the blade in responsetocapillary attractionof a gummed envelope fiapmoving-therepast, but will not force water through the slit when no envelopes are" being moved therepast.

It has been common practice heretofore to" regulate the hydrostatichead ofthe waterin the moistening blades by connecting the blade toan open reservoir and to supply water to the" reservoir from an inverted bottle. The neck' of the bottle normally dips into the reservoir but as the water is-usedand the level drops below a' predetermined value-it permits air to enter the bottle and displace additional water from the-bottle into the reservoir.

Raising or loweringot the hydrostatic head at the moistening blade was accomplished.- by connecting the reservoir to the moistening blade" with a flexible rubber tub'e, and'raising-or'lowering the reservoir andthebottle as aunit. Thiswas objectionable because the bottle and the reservoirwere fairly heavyand a relatively sturdy and complicated m'echanism was requiredto adjustably support them for movement vertically. Furthermore, the flexible rubber tubewas undesirable since it was subject to injury anddeterioration in use.

A specific object of the present invention is to eliminate the necessity of adjustabl-y supporting-- the entire water reservoir and bottle and pro-- vide a simplerand mechanically more desirable way of accurately adjusting the hydrostatic head of the water in the moistening blade.

In envelope-sealingmachines of the general type referred to employing a moisteni-ng blade having aslit therein, it is'important that thegummed flaps of the envelope-approach andleave the blade at relatively exact angles; Afeature of thepresent invention' is a particularly simple and effective envelope-flap guiding struc'-' ture for con-trolling the path of the envelope flap -past the moist'ening blade.

Still another object'of the invention is to pro vide asimplified controlling mechanismfor starting and stopping an envelope-sealingmachine and regulating the water flow to the moisteningblade of the machine;

The manner in which the; foregoing objects and features are obtained will now be explained" by describing a particular embodiment-ofthe invention in detail, with reference to the draw-' ings- In the drawings: I r V Fig. 1 is a vertical section through an envelopesealing machine incorporating a water su ply system-in accordance withthe invention;

Fig. 2 is-a detail verticalsection, taken'substantia-lly in the p1ane-IIIIof Fig; '1, but showing the valve in adifiei'ent position;

Fig. Bis a detail section, similarto Fig. 2'; but' showing the valve'in stillanother position;

Fig. 4 is a skeleton view, partly sectiomtaliensubstantially along the line IV-JV of Fig. 1,

showing the mechanism in' inactive posi tidn;

Fig. 5- is a viewsi-mil'ar to 4,-b-ut showing the mechanism inprimi-ng position; Fig. 6 is a detail, horizontal section, taken substantially in the plane VI-VIof Fi-g. 4;

Fig. 7 is'a detail-vertical section, taken sub stantially in the planefVIP-VII of Fig. 1; v

Fig. 8 is a-detail, horizontal section, taken sub stantially in the plane VIII-VIII ofFig. 1

Fig. 9 isa detail'vertical section, taken in the plane IXI-X of Fig.8; and i Fig. 10 is a-detail, vertical se'ction, taken in the plane X-X of Fig. 8';

Referring first to Fig, 1, there is disclosed. a portion of an envelope-sealing machine incorpo'q rating a feed table- I- along which the bodiesof' envelopes are adapted to slide. This table: I has an exposed edge" 2"wl'iich'separates the flaps or the envelopes'from' their bodies, the gummedsur faces of the envelopes moving past a m-oistenirigi blade 3; which, as shown to best advantage. Fig. 9, has a central passage 4 filledwith'wa'ter' and a narrow slit 5in' itsundersurfacethrough which the water exudesontotheigummedsurfaces of the envelopefl'aps as tney'aremoved therebelow; The"generalconstructionas so far described, is old, thep-re'seri't' invention residing 'in details of adjustmentan'd tne'method or 'supplying water to the passage iii thebla'de 3 and I2; which are in fixearaanoni to eacho'thr and support the flap-Iii r'ii'ng' mechanism; The moisten'i'ng blade 3 ,a i iy sup ported on the frame elements 'fdr'jlateral "slidi'rig' movement (with reference to Fig 1) intoand out of opera:

The machine includes namelemments HT, Il'" tive position. Thus it is secured to a supporting member I4 having a handle I5 thereon. When the blade 3 and the member I4 are moved to the left (with reference to Fig. 1) as far as they will go, they are releasably locked in this position by a latch I6 which is pivotally supported on the frame and carries at its outer end a large roller I 1 which engages in a recess I8 in the handle I5. As clearly shown in Fig. 1, the latch I6 is curved and it is formed of resilient material so that it can yield sufficiently to permit the roller I1 to be moved along the handle I 5 into the recess I8.

The central passage 4 in the blade 3 communicates with a passage I9 in the supporting member I4, and when the supporting member is in operating position in the machine, as shownin Fig. 1, passage I9 communicates with a passage 20 in a hollow bracket 2I, which is removably supported on the frame member II. A watertight connection between the member I4 and the hollow bracket 2| is insured by interposing a resilient gasket 22 between the members I4 and 2 I respectively.

The manner in which the bracket 2! is detachably mounted on the frame member I I is shown in Fig. 8. Thus there is formed integrally with the bracket 2I a cross member 24 which is secured by nuts 25 to the ends of a pair of studs 26-26, the studs being screwed into the frame member I I. By simply removing the nuts 25 the bracket may be removed from the machine.

Referring now to Fig. 9, which shows the body 21 of an envelope positioned above the table I and the flap 28 of the envelope positioned below the moistening blade 3, it will be observed that the flap 28 is supported on each side of the moistening blade by a pair of rods. 29-29, and these rods are so positioned that their upper surfaces are slightly above the level of the lowermost part of the moistening blade 3 so that the envelope flap 28 is pressed against the moistening blade as it passes thereunder. The purpose of these rods 29-29 is to provide a readily adjustable structure for supporting the envelope flaps in the proper position relative to the slit 5 in the moistening blade 3, to accurately control the amount of water to be deposited upon the gummed surface of the flap passing across the slit 5 of the sealing blade.

In accordance with the present invention, a simple and accurate adjustment of the rods 29 is provided for by eccentrically mounting these rods on the bracket 2|. Thus as shown in Fig. 8, each rod 29 has a reduced end section 30 which is eccentrically disposed with respect to the axis of the rod 29, and is fitted in a mounting hole 3| in an upward extension 32 of the bracket 2I. By rotating each rod 29 about its eccentric extension 30, it may be'adjusted into a desired position of elevation and then locked in that position by tightening a nut 33 threaded on the free end of the-extension 30.

The adjustment of the rods 2929, as shown in Fig. 9, is set for normal operation on average envelopes, but should a greater amount of water be desired on the gummed surface of the flap, the left rod 29 may be adjusted so that the flap leaves the moistening blade at a flatter angle. If less water is required, the left rod 29 may be adjusted in the opposite direction.

The right rod 29 is adjustable for accurately regulating the tension of the envelope flap as it passes across the moistening blade slit 5.

In practice the rods 29 can be quickly adjusted for normal operation by removing the bracket 2| from the machine and setting the rods to predetermined positions by means of gauges.

The axes of the extensions 30 are parallel to the axes of the rods 29, although offset therefrom, so that regardless of the positions of adjustment of the rods 29, they always lie at the same angle relative to the moistening blade 3.

Referring to Fig. 9, each envelope is moved from left to right along the table I; with the body of the envelope 21 on the table I and the flap 28 of the envelope below the table. As each envelope is initially started along the table I, its

flap extends substantially vertically downward,

and means must be provided for bending the flap upwardly into the approximately horizontal position shown in Fig. 9. Of course after the flap reaches and passes above the rods 29, the latter hold the flap up against the moistening blade 3. To initially bend the envelopes upwardly, and enter them over the first rod 29, a deflecting vane I0! is provided.

As shown in Figs. 8 and 9, this vane IOI is inclined upwardly toward the upper surface of the right rod 29 and has a concave curved leading edge I02 against which the edges of the downwardly extending envelope flaps hear so that as the envelopes advance from left to right, the flaps are folded upwardly, and directed over the right rod 29, then under the moistening blade 5 and over the left rod 29. As the envelopes are fed along the table I, they are guided in the horizontal plane, by contact of the flap edge of the envelope against a vertical guide plate I 04 (Figs. 1 and 8). The vane IOI may be conveniently mounted on this guide plate I04 by providing the vane with a downwardly bent flange I05 which lies flat against the guide plate I 04 and is secured thereto as by screws I06.

The rear, or trailing, edge I01 of the vane I 0| extends the full length of the rods 29 to facilitate the guiding of selectively wide envelope flaps to the moistening blade 5.

As previously indicated, the bracket 2| is hollow and serves to conduct water to the moistening blade. This water is supplied from an inverted bottle 35 (Fig. 1) which bottle is supported on the left end of the bracket 2I. Thus the bracket 2I has at its left end an upstanding portion 36 having a vertical passage 31, which passage is open at the top and slidably receives the lower end of a valve housing 38 secured to the neck of the bottle 35, as at, 3811. This valve housing 38 defines at its upper end (as shown in Fig. 1) a valve seat 39 adapted to be closed by a valve 40 on the upper end of a valve stem 4|, which is slidably supported in apertures 42 and 43 in the valve housing 38. The valve 40 is provided solely for the purpose of permitting re moval and replacement of the water bottle 35, in inverted position as shown, without leaking. Thus whenever the bottle is in operative position, as shown in Fig. l, the lower end of the valve stem 4| rests on a projection 44 in the bracket 2I which lifts the valve 40 clear of its seat 39, The valve housing 38 has apertures 45 therein, permitting free flow of water or air through the valve housings when the valve housing is in open position. The apertures 45 also permit filling of the bottle with water.

In operation the flow of water from the bottle 35 into the hollow bracket 2| is controlled by the extent to which air is admitted to the bottle to displace the water therein. 'Air is admitted into the bottle through the rotatable sleeve 41 of a control valve. .Thus this sleeve 41 is rotatably fitted in an open top vertical hole in the bracket member 2|, offset from the neck of the bottle 35. This hole communicates at one side through a horizontal passage49 with the passage 31 in the upstanding portion of the bracket leading into the bottle 35. The valve sleeve 41 is open at the top and has secured thereto a crankarm 50 through which it can be rotated through approximately 80". a

The sleeve 4'! has a port 5| therein which is moved into and out of registration with the passage 49 in response to oscillation of the sleeve t! by the crankarm 56. Fig. 3 that the port 5| has asloping upper edge 52 which merges at its upper end into a slot or notch53.

When the valve sleeve 41 is in one extreme position of oscillation, as shown in Fig. l, the port 5| is completely out of registration with the passage 49 so that there is no path for the entry of air into the bottle 35 through the valve. Hence although air already in the hollow bracket 2| would flow upwardly in the bottle 35' and displace a limited amount of water down into the hollow bracket, the highest level of water in the hollow bracket would be substantially as indicated at 54, which is below the level of the lowest part of the slit in'the moistening blade, the latter level being indicated at 55. Therefore, with the valve adjusted to the position shown in Fig. 1, water will not be delivered from the bottle 35 through the hollow bracket 2| and discharged from the moistening blade.

When it is desired to start operations, the Valve crank 5|] is rotated through substantially 80 by a mechanism to be described later, which brings the slotted portion 53 of the port 5| into registration with the passage 49, thereby providing a free path for the entry of air down through the valve sleeve'and through the slot 53 and passage 49 into the bottle 35. Air enters the bottle and displaces water therefrom until the water level in the hollow bracket reaches the upper end of the slot 53, as shown in Fig. 3. As is clearly apparent from Fig. l, the water level under these conditions is above the level of the moistening blade 3, the level of the latter being indicated by the line 51 in Figs. 2 and 3. This primes the system by quickly driving out all air from the hollow bracket and the moistening blade, some water being also discharged and collected in a catch basin 58 from which it may be carried through a suitable trough 59 to a drip pan.

In operation, the valve sleeve is left in the priming position last described and shown in Fig. 3 only for a moment. Thereafter, the sleeve is rocked back into a position such as that shown in Fig. 2, in which only a portion of the port 5| underlying the sloping edge 52 is registered with the passage 49. This prevents further entry of air into the bottle 35 until the water level in the passage 49 drops to the highest portion of the edge, 52, registering with the passage 49. As the water is used up during the operation of the machine, additional air will enter as necessary to maintain the water level at the upper edge 52 of the port.

The sloping upper edge 52 of the port 5| permits a fine adjustment of the water level in the moistening blade. It will be observed from Fig, 2 that with the valve adjusted as shown therein, for normal running, the uppermost portion of the open port is very slightly above the level 51 of the moistening blade slit, so that a slight head of water is provided at the slit. With the optimum It will be observed from 5. by a screw 66,, to the frame member 3 adjustment of'thewater level, the hydrostatic headat the moistening blade'slit is sufficient to feed water freely through the slit 5 in response to the capillary attraction of a gummed flapthereagainst, but is insufiicient to cause water. to leak through the slit when no envelope flapsarein contact therewith. Under certain conditions,

as when sealing envelopes having very large and the angle of this edge may be varied to provide as great a range of water level as may be necessary under the conditions of operation for which the machine is intended.

At the completion of a run of the machine, the valve sleeve 47. isagain rotated into shut-off posi--v tion, as shown in Fig. 1, thereby preventing leak-. age of water through the moistening. blade.

The valve 41 is rotated through a suitable-- .mechanism by a control handle 66, which handle also controls. the starting and. stopping of the;-

power mechanism. of the machine- Thus the handle 66 is mounted on the right end of a shaft 6.| which is journaled in bearings ,62and 63 in the frame members l2. and II, re spectively. Therev is mounted. on the rear end of the shaft 6| a crankarm. 64 whichis connected bya pin and slot connection to the lower end of a lever 65 (Fig. 4) fulcrumed. near its center At its upper end, the lever 65. is pivotally connectedv by a screw 61 to one end of a link 68, the other end; of which is slidable along a horizontal guide bar 12 which is supported on the frame member Thus the link 68 may be formed. of sheet metal and have a wing 69 (Fig. 6) extending forwardlyover the guide 12 and then down, to. form a.

lip 16 (Fig. 1) bearing against the front face'of the guide 12. The link 68. has another, bifurcated. wing extending rearwardly from the wing .69 and defining a slot. '13 which receives. anupwardly: extending crank 14 on the crankarm 50.

It will be apparent from the foregoing description that in response to oscillation of the handle.

60, the crankarm 56 and, the valve sleeve. will be oscillated.

As has been previously indicated, the handle 60.

also preferably controls a switch for starting and:

stopping the motor that powers thev sealing machine. Referring to Fig. 1, such a switch is indi.

cated at 80, and. is of the toggle type, having. a.

bifurcated handle 8| adapted to be intercepted by a crankpin 82 on a hub member 83 pinned to the shaft 6|. When the handle 6|] is in oil posie tion (in the position shown in Fig. 7.), the switch; handle 8| is in clockwise position. To start the machine, the operator rocks the handle 60 clockwise through approximately During the initial portion of this movement, the pin 82 rocks. the switch handle 8| counterclockwise to start,

the motor of the machine, after which the pin. 82 leaves the slot in the bifurcated handle 8|. When the machine is to be shut down, the handle 60 is rocked counterclockwise back into its original position, and during the final portion of this, motion the pin 82 again engages the bifurcated handle 8| and rocks the handle into ofi" posi-- tion.

In the two extreme positions of the handle 60.

'a pointer 66c thereon abuts against stop pins 601) and 600, respectively,

,It was previously stated, in connection with the description of the valve, that when the machine is started, the valve 41 is rotated through its full range of movement to carry the slot 53 (Fig. 1) into registration with the passage 49, and then the valve is retracted to bring the valve port into running position, as shown in Fig. 2. In order to prevent the valve from being left in starting position, which would waste water, a spring mechanism is provided to automatically rock the shaft Bl away from starting position whenever the handle 60 is released. Thus referring toFig. 1, there is mounted on the hub 83 a disc 85 cooperating with a spring detent ball 86 which is supported on a bracket 81 secured to the frame of the machine, the bracket 81 also supporting the electric switch 80. Referring to Figs. 4 and 5, the disc 85 has three detent notches 88, 89 and 90, and a straight rise 91. When the handle 60 is in "ofi position, as shown in Fig. 4, the ball detent 86 is in the notch 88. The operator first rocks the handle 60 clockwise until rotation is stopped .by abutment of the pointer 60a against the stop pin 60b, in which position the rise 9| on disc 85 depresses the ball detent 86. shown in Fig. 5, andthe ball detent 86 is constantly exerting a force tending to reverse the handle 60. If the operator-then releases the handle, the detent will reverse the disc 85 and the shaft 61 sufiiciently to carry the slot 53 (Fig. 1) of the valve sleeve 55 clear of the passage 49, but with the highest portion of the sloping edge 52 in registration with the passage 49, thereby providing the maximum working flow of water.

' If a smaller flow is desired, the operator rocks the handle 60 back to bring either the notch 90 or the notch 89 into engagement with the hall detent 86. In ordinary practice, three positions of adjustment involving the notches 89, 90 and the straight rise 9| provide a sufiicient latitude of adjustment. Obviously, however, if desired, a larger amount of smaller detent notches could be provided, to give a finer adjust t.

.Summarizing the operation of the machine, clockwise movement of the handle 60 from the ofi position shown in Fig. 4 into priming positionshown in Fig. 5, actuates the switch 8| to start the motor of the machine and floods-the moistening blade to eliminate all air therefrom and insure immediate operation thereof. Thereafter release of the handle 60 permits it to automatically be retracted by the straight cam surface SI and the ball detent 86 into working posi-. tion of maximum flow. Further manual retraction of the handle to bring one of the notches 90 or 89 into engagement with the ball detent 86 reduces the fiow of water to the moistening blades. During the adjusting movements of the handle Bil to regulate the flow of water, the pin 82 is beyond the point of contact with the biiurcated switch handle 8! and doe not affect the switch. When the machine is to be shut down, the handle is simply rocked back into starting position, as shown in Fig. 4, which returns the switch handle 81 to oil position, as shown in Fig, '7, and completely closes the valve sleeve 41.

Although for the purpose of. explaining the invention a specific embodiment thereof has been describedin substantial detail, it is to be understood that various changes may be made in the particular construction shown without departing from the invention, which is to be. limited only to the extent set forth in the appended claims.

The parts are then in the position I claim:

1. In an envelope-sealing control member and means for rotating it between first and second extreme positions, said sealing machine including envelope flap-mois- "tening means and means for supplying water within its range of movement.

thereto, means for varying the hydrostatic head of the water supplied, between extreme values in response to rotation of said control member, and means for controlling the movement of said control member, comprising a cam element and a spring detent element, one of said elements being ecured to said control member for rotation therewith and the other element being anchored in stationary position, said cam element having a rising cam surface for compressing said spring detent in response to movement of said control member into its full on position, whereby the detent partially retracts the control member when the latter is released from manual control, said means for varying the hydrostatic head of said water supply increasing said head to an excessive value to prime said moistening system While, and only while, said control member is in said extremeposition.

2. Apparatus as described in claim 1, in which said cam member has a plurality of detent recesses therein for yieldably engaging said detent and yieldably retaining said control member in one of a plurality of predetermined positions 3. In apparatus of the character described, in combination, means for supplying liquid at a variable hydrostatic head including a fixed conduit, a container positioned above a portion of said conduit and connected thereto whereby liquid can flow from said container into the conduit in response to admission of atmospheric air to said container, valve means including an open top chamber having a port in the side thereof communicating with said conduit at a point below said container, and means for varying the height of the upper edge of said port, whereby air enters said container through said valve means to displace liquid from said container into said conduit until the liquid level in the conduit rises to the level of the upper edge of said port.

4. In apparatus for controlling the flow of liquid to a moistening device having an orifice, in combination, a liquid container, means forming a conduit connected to said container and said device for conducting liquid from said container to said device, means for restricting the flow of liquid from said container to maintain the liquid level in said moistening device below the orifice therein when said device is out of use, and means for selectively adjusting said restricting means to raise said liquid level to any one of a plurality of positions above said orifice.

5. In apparatus for controlling the flow of liquid to a moistening device having an orifice, in combination, aliquid container, means form; ing a conduit connected to said container and said device for conducting liquid from said container to saiddevice, means for restricting the how of liquid from said container to maintain the liquid level in said moistening device below the orifice therein when said device is out ofuse, and means for selectively adjusting said restricting 'means to raise said liquid level to any one of a machine, a rotatable container a predetermined amount of air and thereby selectively adjust the liquid level with relation to said orifice.

6. In apparatus for controlling the flow of liquid to a moistening device adapted to be installed in a power-operated envelope sealing machine or the like having a manually operable starting lever, wherein the envelopes are fed automatically to the moistening device, said moistening device having an orifice, the combination of, a liquid container, a conduit connected to said container and to said moistening device for leading liquid from the former to the latter, and means responsive to operation of said starting lever to operate said machine for varying the hydrostatic head of the liquid in relation to the level of said orifice, said means including a valve associated with said conduit and operable to connect said conduit with the atmosphere to meter air into said container.

'7. In apparatus for controlling the flow of liquid to a moistening device adapted to be installed in a power-operated envelope sealing machine or the like, wherein the envelopes are fed automatically to the moistening device, said moistening device having a downwardly facing orifice, the combination of, a conduit having its outlet end connected to said moistening device, a liquid container mounted on and supported by the inlet end of said conduit, and a valve in said conduit operable to meter atmospheric air into said container to vary the hydrostatic head of liquid in said moistening device relative to said orifice.

8. In apparatus for controlling the flow of liquid to a moistening device adapted to be installed in a power-operated envelope sealing machine or the like having a manually operable starting lever, wherein the envelopes are fed automatically to the moistening device, said moistening device having a downwardly facing orifice, the combination of, a conduit having its outlet end connected to said moistening device, a liquid container mounted on and supported by the inlet end of said conduit, a valve in said conduit operable to meter atmospheric air into said container to vary the hydrostatic head of liquid in said moistening device relative to said orifice, and means connected to said valve and responsive to operation of said starting lever to initiate operation of said machine to connect said conduit with the atmosphere for raising the hydrostatic head of liquid in said moistening device relative to said orifice.

9. As an article of manufacture, a liquid conduit for conducting liquid from a container to a moistening device, said conduit comprising an elongated rigid pipe the outlet end of which is adapted to be connected to said moistening device, means forming a liquid inlet chamber at the other end of said pipe adapted to be connected to said container, means forming an air inlet chamber on said pipe, means in said air inlet chamber for cutting off communication between said pipe and the atmosphere, said liquid and air inlet chambers being disposed adjacent one another, means forming a port between said chambers, and a rotary valve operatively mounted in one of said chambers for varying the vertical dimension of said port.

10. In apparatus of the character described, in combination, a support, a moistening device detachably mounted on said support, a rigid liquid conduit rigidly mounted on said support, means forming a separable liquid-tight connection between said device and the outlet end of said conduit, a liquid container detachably mounted on and supported by the inlet end of said conduit, and valve means on said conduit for metering air into said container for variably controlling the hydrostatic head of the liquid in said moistening device,

11. In apparatus of the character described, in combination, means for supplying liquid at a variable hydrostatic head including a fixed conduit, a container positioned above a portion of said conduit and connected thereto whereby liquid can fl-ow from said container into the conduit in response to admission of atmospheric air to said container, valve means including an open top chamber having a port in the side thereof communicating with said conduit at a point below said container, means for varying the height of the upper edge of said port, whereby air enters said container through said valve means to displace liquid from said container into said conduit until the liquid level in the conduit rises to the level of the upper edge of said port, said height varying means including a cylindrical sleeve fitted in said chamber and having a port adapted to be variably registered with the port in said cylinder, and means for rotating said valve sleeve.

12. Apparatus as described in claim 11 in which at least one of said two ports has a sloping upper edge, whereby the height of the passage defined by the two said ports when the valve is in partially open position is determined by the height of that portion of said sloping edge of the one port which is in registration with the other port.

13. In apparatus of the character described, in combination, a support, a moistening device detachably mounted on said support, a rigid liquid conduit rigidly mounted on said support, means forming a separable liquid-tight connection between said device and the outlet end of said conduit, a liquid container detachably mounted on and supported by the inlet end of said conduit, and valve means supported by said conduit and disposed between said moistening device and said liquid container and forming communication between the atmosphere and said liquid container for controlling the hydrostatic head of the liquid in said moistening device.

COMMODORE D. RYAN.

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