Abstract: A ventilation or aeration device comprising an air vent for warm and/or fresh air. When used in a vehicle the device may serve as a window defogger by blowing warm air as well as a ventilator. In normal operation the vent may be manually manipulated as desired. When used as a defogger, opening of the warm air passage automatically directs the vent towards the window to be defogged or defrosted.

Abstract: The invention relates to a slotted outlet for the delivery of air into an interior space, with a plate which can be inserted into the wall of the interior space (inside room) in order to close an air intake passage and which contains at least one outlet slot and at least one air guidance lamina which is arranged on the inside of the plate.

Abstract: The invention relates to a mash and wort tub of rectangular cross-section, having heater bottom inclined upwardly from its edges in a roof-shaped manner.

Abstract: A cooking apparatus, for simultaneously cooking a number of products, each a filling between two slices of bread buttered on their outer faces and toasted, has two oppositely arranged but otherwise similar cooking units mounted in frames, the lower one fixed, the upper one hinged to the lower. Each unit is a metal casting with a face plate and a series of hot plates, each with a rim extending from the face plate and with a peripheral cutting bead, and a concavity within the rim. The cooking units are simultaneously heated by electric heating elements on their reverse faces, and when the upper one is brought down onto the lower one, in the hot plates of which the products to be cooked are placed, the cutting beads of corresponding hot plates of upper and lower units coact to cut through the bread slices to trim excess, and to seal the edges of the slices together.

Abstract: A rolling-compressing apparatus for forming loose fibrous material into continuous dense cylindrical core which is cut into individual rolls of desired length. The core forming channel is confined by a plurality of circumferentially arranged compression rollers.The improved suspension and drive mechanism of the compression rollers, subject to this invention allows the necessary angular movement of the compression rollers relative to the drive shafts of the main power drive train and utilizes effective means for the transfer of the driving torque.

Abstract: A compactor arrangement is proposed for compacting waste in skips; that is to say, open-topped, truck-borne containers such as are used by builders and municipal authorities. The compactor arrangement includes a compactor having a pressure platen which can move generally upwardly and downwardly out of and into a skip, means for receiving and locating a plurality of skips, and means for effecting relative movement between the compactor and the receiving and locating means, whereby in use the pressure platen of the compactor can be caused to make successive compacting strokes on different skips in turn.

Abstract: A marking device for round objects such as tennis balls which has a vertical stand, an object holder slidably secured to the bottom of the stand and movable through 180.degree. to present a flat or a curved surface to the object, an inverted "L" shaped bracket vertically and slidably mounted on the stand, a type holder resiliently carried on the bracket, character type pivotally and removably secured on the holder, and a handle means to move the type holder toward an object on the object holder.

Abstract: There is disclosed a compact print head utilizing printing bands, coaxial drive wheels, a single selector for the drive wheels and support structure by which two or more lines of data can be printed on a record or other suitable surface.

Abstract: 4. In a projectile comprising a casing having a first electrically conducg part, a second electrically conducting part and an electrically insulating part interposed between said first and second conducting part, a proximity detector comprising:(a) a bridge circuit;(b) said bridge circuit having a first terminal connected to said first electrically conducting part of said projectile casing; and(c) said bridge circuit having a second terminal adjacent to said first terminal and connected to said second electrically conducting part of said projectile casing.

Abstract: Both an operating link and a locking hook member are secured on a shaft rotatably mounted on a hopper door. The hook member cooperates with a locking lug fixed relative to the hopper for securing the door closed. The operating link is both pivoted and pushed or pulled by a crank actuated by retainable handles for operating the hook member and opening and closing the door.

Abstract: Systems for anchoring a load or container on a flatbed and particularly adapted to be used with existing containers without alteration thereto and which systems are simple and readily and safely anchor a container on a flatbed. Such load anchoring system comprises a beam secured on the flatbed, a slideway formed in the beam, an anchoring member slidable in the slideway and having a prong engageable endwise into an aperture in the corner post of a container, and a lever pivoted relative to the prong to register with the anchoring member in the path of displacement thereof to block the prong against retraction from the aperture in the corner post.

Abstract: The invention relates to a highway safety device and in particular to a device which is constructed and arranged to be removably mounted on the window glass of an automobile such that it extends laterally from the automobile so that it may be readily seen by passing motorists. Briefly, the present device comprises a mounting base and a pole extended from the base. A light is mounted on the end of the pole and a fluorescent flag mounted beneath the light whereby passing motorists may easily see that the motorist is in distress and come to his aid.

Abstract: Apparatus in which melting ice is used to activate a dye formation in producing a color indication of thawing.

Abstract: An indicator pointer is arranged between a dial board and a viewing window so as to swingably move over the face of the dial board in response to rotation of a spindle of a movement of the indicator gauge. Illuminating means such as a light emitting diode (LED) is disposed in the pointer to illuminate a relatively large portion of the pointer. Opaque paint is coated on the front surface of the pointer to conceal the illuminating means.

Abstract: In apparatus for applying fluid adhesive to strips to be wound helically to form a tube, the strips are led over a tank in step-wise configuration with successive strips laterally and vertically offset relative to one another but overlapping so that an upper strip partially overlaps the next lower strip. Liquid adhesive pumped from the tank is delivered onto the uppermost strip which then passes through scrapers which scrape surplus adhesive off the strips so that at least part of the surplus flows off a lateral edge of the uppermost strip onto the next lower strip. If there are more than two strips, the process is repeated so that surplus adhesive is flowed at least in part from each strip to the next lower strip. Any surplus not retained by the strips flows back to the tank.

Abstract: A heat exchanger is interposed between the exhaust duct of a water boiler and the chimney or flue, and a water conduit, connected to the water return line of the heating system, is disposed within the heat exchanger in heat exchange relationship with the exhaust gases. In this manner, up to 85% of the thermal energy within the exhaust gases is recovered and imparted to the water for pre-heating the same prior to the transmission of the pre-heated water into the boiler for additional heating, or alternatively, directly into the water heating system. A filter assembly is preferably interposed between the heat exchanger and the chimney or flue so as to filter the cooled gases prior to the emission of the same into the atmosphere. As a result, solid particles, and a substantial portion of sulfur dioxide, is removed from the exhaust gases so as to reduce pollution conditions.

Abstract: Apparatus for limiting the rotational speed of an internal combustion engine by monitoring the time interval between ignition impulses produced when a breaker switch in the primary circuit of the ignition coil opens. A pair of sequentially operable timers are started for each ignition pulse with the second time interval enabling a delay means coupled between the source of pulses and a control gate of a controlled switch connected across the breaker switch through an impedance. When a following pulse occurs during the second time interval, indicating a limiting rotational speed, the slightly delayed pulse triggers the controlled switch and the ignition pulse is shunted through the impedance with the resulting secondary voltage in the ignition coil being insufficient to cause a spark, thereby limiting the speed of the engine.

Abstract: An electric motor with output reduction gearing such as is provided for windshield wipers, is operated in response to a vehicle speed control system and is coupled through an electromagnetically operated clutch to a worm gear drive providing further reduction gearing that controls the accelerator pedal of a vehicle engine through a cable drum and a cable connection. When the electromagnetic clutch is released the compression spring of the accelerator pedal restores the latter and the drum and worm gear connected thereto to the engine-idling position. A resistance strip on the driven clutch member is sensed by a wiper contact to indicate or check on the position of the accelerator control and components moveable therewith.

Abstract: In a feedback control system for maintaining the air/fuel ratio of a combustible mixture fed to an internal combustion engine at a preset ratio based on the output of an exhaust sensor, a control signal producing circuit having a proportional amplifier and/or an integrator is constructed so as to vary the proportionality constant or the time constant for the integration in dependence on the temperature and flow velocity of the exhaust gas, with a purpose of avoiding an error in the control attributable to a variation in the output characteristic of the exhaust sensor with variations in the condition of the exhaust gas by superficially shifting the aim of the control from the preset ratio to a provisional ratio.

Abstract: An air-fuel ratio regulator for internal combustion engine, used mainly in the intake system of an automotive engine, comprising an air passage leading from the intake passage or the atmosphere upstream of the throttle valve in the carburetor to the intake passage downstream of the throttle valve, a control valve for opening and closing the air passage, and differential-pressure responsive means for actuating the control valve. The differential-pressure responsive means, consisting of a pair of vacuum chambers on either side of a diaphragm, opens the control valve during the high-speed operation or in rapid deceleration where the intake manifold vacuum generated downstream of the throttle valve increases rapidly, in order to prevent the intake air-fuel mixture from becoming rich, and to maintain the air-fuel ratio appropriately.

Abstract: A vacuum signal is produced, which is representative of a function of the flow rate of engine taken air and which is employed for directly or indirectly operating a diaphragm unit of an exhaust gas recirculation control valve, by admitting atmospheric air into a vacuum from a vacuum source by employing a solenoid valve in such a manner that the solenoid valve varies the amount of admitted atmospheric air in accordance with the flow rate of engine taken air.

Abstract: A screen and a stationary screw propeller are arranged in round chambers between the carburetor and intake manifold of an internal combustion engine of an automobile, for example, to substantially increase the efficiency and gasoline mileage thereof.

Abstract: The present invention discloses an ignition system for internal combustion engines. The ignition system is particularly applicable to such engines including a magneto.The ignition system includes a semi-conductor ignition circuit in which a first transistor has its collector-emitter conduction path connected in series with the primary winding of an ignition coil assembly. A resistor is connected between base and collector of the first transistor to permit it to conduct. A control circuit connected between the base of the first transistor and the primary winding, turns the first trnasistor off when it is desired to interrupt the primary winding current.The ignition system also includes a magneto ignition coil assembly which has a low inductance primary winding having a relatively low number of turns. The coil assemblies of the present invention are generally unsuitable for use with conventional mechanical breaker points.

Abstract: A rotary valve system for an internal combustion engine is disclosed. Through the provision of an axially movable valve rotor, the system is capable of variable valve opening duration and timing. Ports in the rotor or in the rotor housing, or both, have edges inclined with respect to the axis of the rotor, so that relative axial movement of the rotor and housing ports effects a change in the timing of valve opening and closing. Valve opening duration is also varied. An actuator system which controls the axial translation of the rotor during operation of the engine considers factors affecting engine performance such as engine speed, road speed and engine loading in determining the optimum valve timing and duration setting.

Abstract: An apparatus for opening a delivery valve in a gas reservoir chamber of a compressed gas operated gun comprises a compressed gas chamber in a cylinder and a gas reservoir chamber adjacent thereto. The gas reservoir chamber is normally closed at the side of the compressed gas chamber by a suction check valve and at the side opposite to the compressed gas chamber by a rod-like delivery valve which also closes a leading hole leading to a barrel bore. The delivery valve is slidably arranged within a through-hole which opens into the gas reservoir chamber at the side opposite to the suction check valve, and is urged by a spring so as to normally close the leading hole, and the rear end of the delivery valve is engaged by a latch lever of a trigger.

Abstract: A radiant heater for burning firewood and the like to heat a living space such as a mobile home or house including an enclosure with a combustion compartment for the burning of the firewood placed in the combustion compartment, a flue pipe positioned outside the living space, an exhaust pipe extending through a wall of the living space and connecting the combustion compartment with the flue pipe, an outside air inlet having an opening to the outside wall surrounding the portion of the exhaust pipe extending through the wall to permit the exterior air coming through the inlet to cool the exhaust pipe and prevent overheating of the wall adjacent the exhaust pipe, an air passageway connecting the air inlet compartment with the combustion chamber, a thermostatically controlled damper in the passageway to control the rate of flow of air to the combustion compartment to achieve a desired heat output thereby providing a thermostatically controlled wood burning radiant heater which utilizes only outside air and autom

Abstract: The present device provides an air duct means disposed between the top end of the heat exchanger of a furnace and the entry port into the flue pipe of the furnace. An electrical blower means is coupled to said duct means to draw hot air therethrough which would otherwise go out to the atmosphere through the flue. The hot air drawn by the blower is redirected to heat, or assist in heating, the building to which the furnace is directing heat, or heat some other facility. An electrical control circuit is connected to the blower means and controls the blower means such that if the furnace is burning fuel, the blower cannot be turned on. The blower can only be turned on after a predetermined time has elapsed from the time that the fuel burning has terminated, so that combustion gases which otherwise would pass through the flue and which might contain harmful ingredients therein, will not be redirected to be used as a source of heat.

Abstract: A fireplace heat system to maximize heat transfer from a fireplace to the surrounding environment of the immediate area outside the fireplace to reduce the heat loss of the fire rising up the fireplace flue and chimney. Maximum heat transfer of the fire in the fireplace is obtained by utilization of thermodynamically short pipes, production of turbulence in the pipes, and pipe length to diameter ratio of less than fifty. The fireplace heat system consists of equal lengths of standard black iron malleable pipe forming U-shaped structures having legs on one side connected together to form U-shaped apparatus. The legs on the connected side of the U-shaped apparatus are positioned above and parallel to the fireplace floor. A forced air blower forces air through an air input manifold which connects the legs of the U-shaped structures. Air is forced through the pipes of the U-shaped apparatus and exits at the top of the opposing set of legs into the surrounding environment of the immediate area of the fireplace.

Abstract: A door latch mechanism, mountable in an oven for engagement with an oven door, includes a base, a latch plate carried on the base by a pair of flanged guide rollers carried on the base and cooperating with a pair of guide slots in the latch plate, and a yieldable over-center urging means pivotally engaged with the latch plate and reciprocably received by a support on the base, the latch plate being carried by the base for movement between an extended position and a retracted position corresponding to open and closed positions, respectively, of the oven door. The mechanism, in one embodiment, further includes a lock for securing the latch plate in its retracted position and a thermally responsive interlock for retaining the lock in a locked position when the oven is operative.

Abstract: The disclosure herein describes a door for covering the oven cavity of a pyrolytic range, which comprises four spaced panels that define therebetween three air cooling passageways providing an insulating effect; inlet and outlet openings are located in the top and bottom edges of the door to allow air to circulate in the passageways to reduce heat loss through the window sections of the door so that the temperature on the front panel of the door, during the high temperature self-cleaning cycle of the oven, does not exceed the allowable limit. The invention is also concerned with providing a continuous gasket on the front wall of the oven portion of the range to trap air on the sides of the oven and to direct it upwards through orifices leading to underneath the top cooking surface of the oven from where it exits.

Abstract: An elongate roofing panel for assembly on a support structure with a plurality of like panels to form a roof covering. The panel has a first elongate edge adapted to be fixed to the support structure; and a second elongate edge opposite to the first elongate edge, adapted to engage the first elongate edge of an adjacent panel to restrain the second edge against movement normal to the plane of the panel. The elongate edges are formed as respective first and second beam elements projecting on opposite sides of the panel for supporting the panel on the support structure, and the panel is formed with ribs spanning transversely between the beam elements for transmitting thereto the load of the panel. Ideally the panel also serves as a solar heating panel, the ribs defining transverse ducts in which a fluid is heated as it is conveyed across the panel from an entry to an exit duct, these latter extending longitudinally from one end of the panel to the other.

Abstract: A pad for use in combination with a bone marrow biopsy needle which is adapted to be slipped over the proximal end of the needle to provide an enlarged surface for distributing the pressure across the palm of the user. The pad includes a generally disc-shaped palm engaging surface along with a needle enveloping sleeve for releasable attachment to the biopsy needle. A bore is formed through the wall of the sleeve to provide communication between the interior of the sleeve and the atmosphere, thereby avoiding transfer of air between the pad element and the lumen of the needle when the pad element is mounted on the needle.

Abstract: A heartbeat rate monitor has a light source, powered by a rechargeable battery, for transilluminating skin tissue. A semiconductor detector which produces an output signal in dependence on light originating from the light source and reflected from the skin tissue, and hence on changes in arterial blood flow, is additionally used, on exposure to ambient light, to produce a current for recharging the battery.

Abstract: The present invention concerns closed circuit breathing apparatus comprising a mask having inhalation and exhalation ducts in communication with a regenerator for regenerating exhaled air. A source of air under pressure is connected to the closed circuit so as to feed unused air into the circuit in such a manner as to draw regenerated air to the mask and to maintain a slight over pressure.

Abstract: A device which provides an aversive stimulus to a child who bed wets while asleep includes a urine detection pad of absorbent material having wire screen electrodes on both sides thereof, and an electrical circuit including an aversive alarm which is triggered when the detecting pad is moistened by a small amount of urine. A preferred embodiment of the device shuts off the alarm within a short time period if the total amount of urine deposited on the detecting pad is below a given quantity. If more than the allowable quantity of urine is deposited, the alarm continues to expose the child to the aversive stimulus. The device may also feature an adjustable threshold in its circuit to permit variation of the total quantity of urine required to continually energize the alarm, as well as selectable sensitivity of the circuit to the initial deposition of urine so that dampness caused by perspiration or humidity will not trigger the alarm.

Abstract: A continuous mechanical ventilator system includes a ventilator known in the art, with a pneumatic circuit connectable to the patient and operating in the normal manner. A bag and bag valve are interposed within the pneumatic connection such that when the value is closed, the patient is on full assisted breathing from the ventilator. When the bag valve is opened, gas from the ventilator passes into the bag from which it may be drawn freely by the patient in an unassisted manner. Electronic controls provide means for varying the proportion of breaths to be assisted by the ventilator to the breaths from the bag which, of course, are unassisted. The exhalation valve normally provided, is normally operatively connected to the ventilator in the usual way, when the device is in the assisted mode. However, during the unassisted mode, the exhalation valve is isolated from the rest of the circuit so that no pressure pulses be fed to the exhalation valve during this time.

Abstract: The cardiac pacer disclosed herein responds to a premature heartbeat by first digitally measuring the time interval between a pair of successive sensed heartbeats and establishing an escape interval for stimulation which is shorter than the measured heartbeat interval. Pacing at this shorter escape interval enables the pacer to capture and control the heartbeat rate. By repeatedly incrementing the digital value representing the escape value on successive stimulated heartbeats, the heart is then caused to slow down until a preselected desired rate is established. Preferably, the sensing and timing between heartbeats continues during the slowdown process so that, if, at any time, a natural heartbeat occurs earlier than the stimulation pulse at the then extant escape interval, the escape interval is reset to a shorter time so that capture will be re-established.

Abstract: An improved tobacco-smoke filter or filter material contains granules of porous activated carbon to which has been applied a nitroxide of the group consisting of the nitroxide 4-oxo-2,2,6,6-tetramethylpiperidino-oxy, the nitroxide 1-nitronyl-3-oxyl-4,4,5,5-tetramethyl-2-phenyldihydroimidazole and mixtures thereof. The carbon may be loaded with 0.5 to 25%, suitably 1.0 to 15%, by weight of the nitroxide. Advantageously such a filter has provision for filter ventilation. For instance, in a triple filter with a center section containing the treated carbon, the said center section and/or the section upstream thereof is ventilated.

Abstract: A process for improving, enhancing or modifying the organoleptic properties of tobacco products which comprises adding thereto a compound possessing the following formula: ##STR1## wherein R represents a straight or branched-chain alkyl, alkenyl or cyclic aliphatic or aromatic hydrocarbon group having less than 8 carbon atoms.

Abstract: Equipment designed to automatically process a photoengraving cylinder through a variety of processes including plating on a metal roll, surface polishing, corrosion, development, printing and the like. In order to make more efficient such processes, this invention is directed to an equipment improvement which can automatically determine the condition of a cylinder during any process steps common to any of such processes, and further move a roller to be processed (hereinafter called a photoengraving cylinder) successively during the whole sequence of steps of work.

Abstract: An apparatus for cleaning cargo or tanker holds of ships is provided having a central support axle extending from the hold floor to the ship deck and on which is a trolley assembly having adjustable spray nozzles which trolley can travel vertically, as well as, rotationally about the support axle.

Abstract: An air release valve, used in a system containing liquid with gas above it, has a float chamber connected to the system and containing a float which normally closes a primary orifice leading through a vertically movable spring-loaded piston to an upper chamber. When the piston is raised by gas pressure in the float chamber to open the primary orifice, a seal pad, spring-mounted above the piston, closes a secondary orifice from the top chamber to atmosphere until the increased pressure in the top chamber moves the piston down to open the secondary orifice. When liquid entering the float chamber causes the float to rise, closing the primary orifice and lifting the piston, the seal pad closes the secondary orifice, trapped gas lowers the liquid and float, and the primary orifice opens.

Abstract: A hose receiving member constructed as a unitary plastic article is specifically adapted to connect an anti-kink corrugated plastic hose to an appliance such as an automatic washer in either a standpipe installation or a laundry tub installation when used with a metal or plastic hose guide member. The plastic hose guide member connects to an outlet pipe of the member near an upper end thereof adjacent an end of the corrugated hose. This guide member has a curvilinear upper surface which curves from a vertical orientation adjacent the end of the hose connection fitting through an arc of at least 180.degree. in a plane including an axis of the outlet pipe. A planar rib maintains the surface in its desired shape. Two retaining ties on the guide member grasp the hose, clamping it to the curvilinear surface, one tie being used to bend the hose approximately 90.degree. and both used for a bend of approximately 180.degree..

Abstract: A device, such as a damper or valve, for use in closing a conduit against the flow of liquid has a chamber surrounding and opening into the conduit. A blade at one side of the conduit is movable through the chamber from a first position within a bonnet into a conduit-blocking position. Means carried by the chamber side walls surround the conduit and are between the conduit and the blade when in its first position and are operable then to coact to seal the chamber against leakage into it and to seal the blade when in its second position. At least one seal is of a type brought by fluid under pressure from a position out of the path of the blade into its sealing positions and is carried by the side wall enabling the seal to engage the blade face exposed to the fluid flow. Means are provided to deliver fluid pressure to the pressure operated seal when the blade is in either position and to relieve the pressure therein when the blade is to be moved.

Abstract: A center pivot irrigation system comprises a plurality of mobile towers spaced apart and aligned in a row with an irrigation pipe extending between and supported atop the towers. The row of aligned towers pivots about a mobile pivot tower located at a water supply. The mobile pivot tower comprises a vertically disposed frame mounted on a pair of wheels. The frame and one wheel are mounted to pivot about the other wheel, and anchoring structure restrains the other wheel from moving during pivoting of the frame and one wheel.

Abstract: A hot and cold water mixer comprising: a mixer body defining a hot water inlet conduit and a cold water inlet conduit opening towards a mixing chamber communicating with a water delivery orifice; the mixing chamber has therein a mixing unit operably driven, by a control handle or knob, between a closed position, a hot water or cold water open position, and a mixing position. The mixing unit comprises a stationary disc of ceramic material having first and second apertures communicating with said hot and cold water inlet conduits, and a movable block of ceramic material having a flat face sealingly sliding against a flat face of said disc; said block has a cavity opening to said flat face and respectively to the side surface to define a water passage from said inlet conduits to the mixing chamber, the width of the block cavity being larger than the distance or spacing between the apertures in said ceramic disc in order to communicate with either or partially with both the apertures in said disc.

Abstract: The present invention is directed to a pulse dampener device especially effective for the efficient damping of high frequency pulses of relatively small amplitude. The invention is characterized by the provision of a low inertia diaphragm assembly disposed in intimately spaced relation to a conduit through which flows the fluid to be damped, said conduit including a rigid partition or baffle member providing for deflection of a substantial portion of the fluid flowing through the conduit to react against the diaphragm in a direction substantially perpendicular to the plane thereof and providing a tortuous path for the fluid from one side of the partition to the other before continuance of its flow.

Abstract: A test plug for sealing an internal passageway of a vessel preparatory to pressure testing the vessel with a fluid. The test plug is particularly designed for use with vessels that are installed below ground level, and is of the type that can be actuated from ground level to provide the desired sealing function. When the plug is intended to seal an internally threaded passageway of the vessel, it includes an externally threaded seal plate that is rotated into threaded engagement with the internal threads by an upstanding stem that is secured to the seal plate for operation from ground level. The seal plate carries an annular compressible gasket adjacent its lower surface, and a squeeze plate is positioned beneath the gasket for movement in an upward direction to compress the gasket against the lower surface of the seal plate. The gasket compression causes lateral expansion of the gasket into sealing engagement with the internal wall of the vessel passageway.

Abstract: This invention relates to an artificial sausage casing and a process for making the casing. In making a regenerated cellulose casing an oxazoline wax is incorporated into viscose in a proportion from about 1-20% by weight of the cellulose content in the viscose, the oxazoline impregnated viscose extruded into a tubular casing, coagulated, and the cellulose regenerated. The casing has excellent handle, flexibility, and peelability from sausages processed therein.

Abstract: The present specification describes and claims an arrangement for filling a vessel which is to be put under high pressure, with freely flowing solids from a storage vessel which is under normal pressure. The arrangement comprises a supply line extending between the storage vessel and the pressure vessel with a pressure sealing valve which can be tightly closed to counter the working pressure in the pressure vessel, and a shut-off valve suitable for sealing the storage vessel, arranged one behind the other in the supply line. The part of the supply line within the pressure vessel has at least one aperture in its wall and extends within a tube which also has an aperture or apertures, the tube and the supply line being so arranged that relative rotational movement there between opens and closes the aperture in the supply line. Thus, when the pressure vessel is full, the solids block off the supply line which is also full.