US2151514A - Method of and apparatus for conveying material containing at least one expansible constituent - Google Patents

Description

March 21, 1939.

W. HElNE METHOD OF AND APPARATUS FOR CONVEYING MATERIAL CONTAINING AT LEAST ONE EXPANSIBLE CONSTITUENT Filed March 9, 1935 3 Sheets-Sheet 1 M2 4 101 g II I 7 y 2 f & w x 11 a 1 I 51/ E T r p/lshm Shake ([6 [HI entana awe IV!!! Heme/7 151,514 METHOD OF AND APPARATUS FOR CONVEYING MATERIAL CONTAINING w. HEINEN Z,

' 5 Sheets-Shet 2 AT LEAST ONE EXPANSIBLE CONSTITUENT Filed March 9, 1955 March 21, 1939.

W- HEINEN March 21, I939.

METHOD OF AND APPARATUS FOR CONVEYING MATERIAL CONTAINING AT LEAST ONE EXPANSIBLE CONSTITUENT Filed March 9, 1935 5 Sheets-Sheet 3 wmiwamvw C Patented M r.21,1939 e r n 1 2,151,514

METHOD OI AND APPARATUS FOR CONVEY- ING MATERIAL CONTAINING AT LEAST ONE EXPANSIBLE CONSTITUENT Will Heinen, Berlin, Germany, assignor to Kali- ".Forschungs-Anstalt G. in. b. H., Berlin, Germany A Application March 9, 1935, Serial No. 10,178

In Germany March 1'1, 1934 8 Claims. (Cl. 214-35) My invention relates to the conveying of ma- It is an object of my invention to provide an terial which'contains at least one expansible conimproved method for the conveyance of materials, stituent, i. e. a gas or vapor, and at least one which cannot be pumped without difliculty, besubstance of different physical constitution, i. e. tween two compartments placed under difierent asolid ora liquid. Q Q pressures. This method comprises equalization of .5

The problem of conveying such materials, 1. e. the pressures in an intermediate chamber bemixtures of a gas or vapor and a liquid or solid, tween the compartments of higher and lower or of several expansible and non-expansible conpressure before the charging or discharging stituents, presents certain dimculties, because thereof, by steady compression or expansion. The

10 such mixtures cannot be conveyed by pumping in steps of charging, discharging, expansion and 10 the usual way, because their expansible consticompression make up together a continuous and tuent, or constituents, which may be included in periodic closed cycle. solid or liquid matter, is liberated and expands, The continuous charging or discharging may be when the pressure on the material is reduced, or performedas a two-cycle or four-cycle operation may be a vapor, which developed from a liquid by means of a suitable piston or the like operating 15 under the same conditions. in a cylinder connected to the intermediate cham- The methods '.which have already been sugher, the piston and the valves for controlling the gested, partly for discharging reservoirs in which inlet and outlet openings of the intermediate a material is held under pressure, and partly for chamber being prefera y Operated in an 9411110- charging reservoirs in which 'a certain pressure matic manner in accordance with the autoinati- 20 exists are mostly unsatisfactory or can only be cally occurring development and expansion of used'for special purposes. gases in the material conveyed.

In the majority of these methods the pressure It is within the scope of my invention to utilize in a plant, which is operated under a predeterthe energy of expansion of the material entering mined pressure, is gradually made equal to the the intermediate chamber for the control of the 25 pressure in the chamber into which the mateinlet and outlet valves, or for the compression rial is charged or from whichit is discharged. step, so that o y l t le en y u be uppl ed In other methods the material which, by way of from without, or for any other purpose.

. example, fshall be charged" from the atmosphere Obviously the various possibilities of operation into a reservoir under pressure, is first'admitted are determined by the operating conditions of 30 to an intermediate tank, the connection of this each individual case and by the properties of the tank to the atmosphere is then interrupted, the materials to be conveyed. In all modifications, pressure from the reservoir is admitted to the w the method Set Out a ov s used n tank and the material is now forced into the principle.

reservoir. In still other methods the material Chemical and other processes may be combined 35 to be conveyed is conducted through several comwith the conveying operation, as will be departments in series, while the pressure is inscribed farther below. creased or reduced stepwise, the compartments e w method y be used for conveying a belng disconnected entirely or partly by means ma e a o e kind described from p 40 of elastic material which is entirely or almost ment under higher pressure to a compartment 40 entirely relieved of pressure by counterpressure. under lower, for instance atmospheric, Pressure.

Apparatus are also known in which the mate- Conversely. Conveying t aterial from rial is extruded by an extrusion plunger and e compartment under lower pressure, to t e forced into a compartment, the extruded body partm t u d higher P ssure.

5 of material acting towards separating the com- In t e fi case e material is admitted partments under different pressures in the manthrough an inlet valve to one end of an interner of a packing. mediate chamber between the two compartments.

Almost all these methods involve the drawback Th s chamber s connected t a'eylihder n which --that the process of discharging or charging the a p sto reeiproeates. and an Outlet v lve is arreservoir under pressure'is a discontinuous or ranged at its other The tWO Valves are D 5 intermittent one. The inevitable escape of gases erably operated automatically from a crankshaft and vapors from the reservoir under pressure, by which the piston is reciprocated. At the bewhich must of necessity be opened for a longer or ginning of a cycle the inlet valve is open and shorter period, causes loss of the escaping subthe outlet valve closed. The piston now starts stance and risk to the operators. for its upstroke from its lower dead-centre posi- 66 tion and admits material into the cylinder, until the inlet valve is closed. The expansible constituent in the material-which, as mentioned above, may be a gas or vapor admixed to, or liberated from, the material, now expands in the intermediate chamber to the lower pressure or to a pressure slightly above this pressure. At the upper dead centre position the outlet valve is opened, while the inlet valve remains closed, and the greater part or the material in the intermediate chamber is discharged into the other compartment during the downstroke of the piston, until the outlet valve closes whereupon the pressure in the intermediate chamber and in the cylinder is changed again to the pressure prevailing in the first compartment,the apparatus being now ready for another cycle.

In the second case the operation of conveying the material from the compartment under higher pressure into the compartment under lower pressure is performed in a similar manner, howeven-the functions of the two valves being now exchanged.

The new method may be applied to the conveying of mixtures of solid and liquid or gaseous constituents and similarly to the conveying of solid substances, which contain or liberate a gas or vapor, and to the conveying of substances which do not liberate a gas or vapor, such as so-called semi-liquids, i. e., granular material, dust, etc., or mixtures of solid and liquid substances, such as mixtures of cold salt liquors. when conveying such substances, a certain quantity of air or gas is enclosed during the compression period and this air or gas expands during the expansion period.

In the drawings ailixed to this specification and forming part thereof various apparatus adapted for the performance of the new method are illustrated diagrammatically by way of example.

In the drawings Fig. 1 is a sectional elevation showing an apparatus for conveying material from a compartment under higher pressure to a. compartment under lower pressure,

Fig. 2 is a diagram showing the two-cycle, and

Fig. 3 is a diagram showing the four-cycle operation of this apparatus.

Fig. 4 is a sectional elevation of an apparatus which is similar to the one illustrated in Fig. 1 but has an enlarged intermediate chamber.

Fig. 5 shows the apparatus illustrated in Fig. 4 equipped with a metering device,

Fig. 6 shows an apparatus with three conveying devices arranged in series on a single intermediate chamber, Y

Fig. '7 shows an apparatus similar to the one illustrated in Fig. 4, but equipped with pipes for directly connecting its intermediate chamber to the first and second compartment and for admitting certain media to the intermediate chamber.

Fig. 8 is a diagram showing the operation of the apparatus in Fig. 1 if the first compartment is under the lower, the second compartment under the higher pressure.

In the following specification and in the claims the term material is meant to include the material proper, for instance a solid substance, and the expansible constituent, i. e. a gas, air or vapor, which is admixed to, or liberated from, or enclosed with, the non-gaseous substance or substances.

Referring to the drawings and first to Fig. 1, the process may be performed in a compartment I placed for instance under a pressure of 20 kgs/cms. The material in this first compartment may be assumed to be a boiling salt solution in course of crystallization. The mixture of crystals and adhering liquor which collects in the lower restricted end oi the compartment I, shall be conveyed into a compartment 3 which is placed under a pressure lower than the pressure in compartment I. In the present instance the pressure in the compartment 3 may be supposed to be equal to atmospheric. 2 is a duct which connects the lower restricted end oi. the compartment l to one end 01 an intermediate chamber il whose other end is connected to the compartment 3. The intermediate chamber ll supports the conveying device which, in the present instance, is a discharging device, and comprises a cylinder 4, in which a piston 5 is mounted to reciprocate, and slide valves 8 and l at opposite ends of chamber ll. 6 is the inlet and 'l is the outlet valve. The piston and the valves may be operated by any suitable means, such as a crank 8 on a shaft 88, a connecting rod 89, a cross head 90, and a piston rod Si in a stufiing box 92 at the upper end of cylinder 4, for the piston, and eccentrics or cams 9 and HI, respectively, for the valves Band I, eccentric rods 99 and Hill, and stui'flng boxes Hand ill! at the upper end of the respective valve casings. Obviously the mechanism for operating the piston and the valves may be modified, for instance by providing separate means for operating the valves, and by connecting the piston 5 to some other devices.

The operation of the apparatus illustrated in Fig. 1 will now be described with reference to Fig. 2 in which pressures are plotted against piston stroke, the vertical movement of the piston 5 from itslower dead centre position 5 to its upper dead centre position 5 being shown horizontal for the sake of convenience. The "clearance is the volume at the lower end of the cylinder I and between the valves 6 and l in the intermediate chamber H which is not swept by the piston 5.

In the lower dead centre position 5 of the piston the inlet valve 6 is open and the outlet valve 1 is closed, as shown in Fig. 1. The piston now moves upwardly toward its upper dead centre position 5 and the material irom compartment I is admitted through inlet valve 5, until the valve 8 closes at c. At this moment the pressure existing underneath piston 5 is equal, or substantially equal to the pressure in reservoir i but, as the piston moves on, vapor develops from the hot liquor adhering to the crystals and expands, until the outlet valve 1 opens at d, shortly before the piston attains its upper dead-centre position 5 The pressure now drops rapidly and becomes equal to the pressure in compartment 3, when the piston has reached its upper dead centre position at e. The piston 5 now returns for its downstroke and expels the material in the cylinder, while the outlet valve 1 is open. At f the outlet valve I is closed and the residue in the cylinder is compressed, until the inlet valve 6 begins to open at a. ,Itis open altogether at b, when the next cycle begins. The compression ratio is determined by the moment, at which the outlet valve 1 is closed, and by the residual volume which is present at this moment in the cylinder and in the clearance. The time which elapses from the moment the inlet valve 6 begins to open, at 0, until it is full open, at b, is determined by the compression pressure at a, by the: properties of the material to be discharged. by the pressure in reservoir I, and by othe factors. Similarly the period, during which the inlet valve remains open (line 11-0) is determined by such factors.

It is tobe understood that the diagram in Fig, 2 illustrates the phases of admission, expansion, exhaust, and compression only in a general way, and that the diagram will be modified, if this is required by particular conditions. For instance the inlet valve 6 may close earlier or later than shown in Fig. 2, in conformity with the greater or lesser percentage of liquid or gas in the material, its higher or lower temperature, etc. Nor is the final compression pressure at a determined exclusively by the desire of obtaining the steadiest pressure gradient practicable from f to b, as in some cases the final compression pressure must be low as against the pressure in compartment I, in order to ensure a favorable inflow into the cylinder 4 at the beginning of the short opening period of inlet valve 6. Similar considerations determine the position of point d, where the outlet valve 1 opens, for the pressure at cl and the moment at which the outlet valve 1 begins to open, must be such as to effect a favorable discharge from cylinder 4. Other factors will also be considered.

The cycle which has been described is of the two-cycle type and comprises one upstroke 5 -45 and one downstroke 5 5 of pistons, two strokes in all. A cycle which comprises two upstrokes and two downstrokes, or four strokes in all, willnow be described with reference to Fig. 3. During the first stroke admission and expansion occur, and the outlet valve I opens as described with reference to Fig. 2, but the outlet valve remains open throughout the second stroke and the material is discharged from e to h. At the beginning of the third stroke the outlet valve I is still open and air, gas, or vapor is drawn into cylinder 4 from chamber compartment 3 (line hg) and partly discharged during the fourth stroke, until the outlet valve I closes at f, whereupon compression occurs along line f-a, and the inlet valve begins to open at a, as described with refererence to Fig. 2.

Any excess of energy which may become available during the admission and expansion periods, may be utilized for operatingthe shaft 88, or the gears of valves 6 and 1, if such are not operated from shaft 88.

It may be favorable to provide a larger clearance volume at the lower end of cylinder 4 than is presented by the plates intermediate chamber I I. proportioned to the piston-swept volume of the cylinder at any desired ratio, may be utilized for regulating the final compression pressure for a given piston-swept volume, or'for effecting a certain degree of preliminary expansion of the material fiowing past inlet valve 6.

The large clearance for the purpose specified is presented by the enlarged intermediate chamber I I in Fig. 4. The outlet valve I, which is here shown as a horizontal valve in a vertical pipe II connecting the chamber I I to the compartment 3, is operated from an eccentric rod I through a camway I03 and a pin I04 on the valve rod I05, or by any other suitable means.

The final compression pressure is obviously determined by the volume of the enlarged chamber II, and is thus regulated once for all by suitably selecting the volume of the enlarger chamber II, as described. If it is desired to effect the afore-. said preliminary expansion of the material, a

This large clearance volume, which may bev certain pressure gradient is produced between the compartment I and the chamber II so that the material flowing past the inlet valve 6 is expanded preliminarily in the chamber II, before its pressure is reduced to that existing in the compartment 3 by the upward stroke of piston 5, as described.

The enlarged chamber II also facilitates the separation of the solid and gaseous or vaporous constituents of the material, the solid constituents collecting for the major part on the outlet valve I at the bottom of chamber I I, while the other constituents penetrate into the piston-swept portion of the cylinder 4. Preferably a screen I2 is provided, where the cylinder 4 is connected to the compartment II. 1

The enlarged intermediate chamber II may also prove useful in cases where it is desired to cool the solid or gaseous contents by means of a flowing liquid, or to perform a chemical process by aid of, such liquid, before the material is delivered to compartment 3, as will be described with reference to Fig. '7.

It may be desirable to meter the material, before it enters the delivering apparatus. An apparatus equipped with a metering device is illustrated in Fig. 5. It is otherwise similar to the one illustrated in Fig. 4. The metering device comprises a vessel I3 which is connected to the conduit 2 at one end, and to a conduit 22 at the other end, which conduit is in turn connected to the compartment I; a metering slide valve I4 in the conduit 22, and an eccentric II4 on the shaft 88, with a rod II5 in a stuffing box I40, for operating the metering valve I4. When the metering valve I4 is open and the delivery valve Ii is closed, as here shown, the metered quantity of material is admitted to vessel I3, whereupon the metering valve I4 is closed and the inlet valve 6 is opened to admit the metered quantity to chamber I I for further treatment, as described. In this apparatus the screen I2 is dispensed with and the lower end of piston 5 enters the chamber II in the lower dead-centre position of the piston.

.There may be provided in a similar manner a second metering device (not shown in the drawings), On the other side of the delivering apparatus, between the chamber I I and the compartment 3, if desirable to meter the material treated in the chamber II before entering the chamber 3.

If it is desired or necessary to equalizethe pressures in the metering vessel I3 and the reservoir I, after the vessel has been emptied, a pipe I6 is arranged for connecting the vessel I3 to the reservoir Land a valve I5 is arranged in the pipe for making and breaking the connection between I3 and I. The .valve I5 is operated by an eccentric IIB on shaft 08 and a rod III in a stufiing box H50, and opens when the vessel I3 has been emptied.

It may happen that the pressure gradient be- ,tween the compartments I and 3 is so great that it cannot be overcome in a single cylinder 4. In this case, as illustrated in Fig. 6, several devices are arranged in series, on the chamber II, as shown for three individual apparatus I, II, III in Fig. 6. Each apparatus is equipped with a cylinder 4', 4" and 4", and a piston 5, 5 and 5", respectively. The pistons are operated from shaft 80 by cranks 8', 8" and 8", respectively.

A single outlet valve is arranged at the end of r If large quantities of material shall be conveyed from the compartment I to the compartment 3. and if this must be effected rapidly, several apparatus may be provided, one beside the other, for simultaneous operation. A particularly high eiilciency is obtained by connecting the individual apparatus to a single driving mechanism, as in this manner the power demand of the individual apparatus may be reduced.

The enlarged intermediate chamber II may be connected, to the second compartment 3, to the first compartment I and to pipes for supplying to the chamber certain reagents, as will now be described with reference to Fig. 7. Here I1 is the pipe which connects the chamber II to the compartment 3, by-passing the outlet valve 1 in pipe I1, and 20 is a control valve for this pipe. The valve 20 is operated from an eccentric 20I on shaft 88 by a rod 202 which moves in a stufiing box 200 at the upper end of the valve casing. A cock I90 or other suitable means in a pipe I9 may be provided for connecting the pipe I! to the ambient air independently of valve 20. I8 is the pipe which connects the chamber II to the compartment I, and this pipe is equipped with a valve I5 which is operated like the corresponding valve in pipe I6 (Fig. 5).

Any number of pipes such as 22, 23, each equipped with a cook or the like 220 and 230, may be provided for supplying liquids or the like to the chamber II, with the object of effecting reactions and/or cooling, as mentioned above, but also for condensing vapors or gases, for instance during the expansion period. Air, gases or the like may also be admitted during or after the delivery period to scavenge the apparatus, or to assist in the discharge of the material.

An example for the operation of valves I5 and 20 will now be described. If the final compression pressure at a (Fig. 2), is appreciably lower than the pressure in compartment I, it may occur that the solid and other substances separate out from the material when the inlet valve opens, and this quite particularly if It opens slowly, whereby the inlet valve may become clogged. This is prevented by admitting pressure from compartment I through valve I5, before the inlet valve 6 opens, so that any desired pressure may be produced in the chamber II, and the inlet valve 6 may then be opened abruptly without detrimental consequences.

Valve 20 permits eflecting an outflow of material at any point of the expansion line c--d, independently of the outlet valve I.

Cock I90 is opened, when it is desired to separate the gaseous constituents of the material from the solid ones, after the material has been dropped into the compartment 3 through the outlet valve I. The gaseous constituents now escape from cock I90 and may be collected in order to recover the heat stored therein, if any, or for any other purpose. The separation is particularly important, if it is desired to rapidly dry the solid constituents.

My invention may also be adapted for the conveying of material from a compartment under lower pressure to one under higher pressure. Referring again to Fig. 1, the second compartment 3 is now supposed to be under higher and the first compartment I under lower pressure, the material being again conveyed from I to 3. Supposing that a semi-liquid material, for instance a granular substance, a powder or the like, shall be delivered from compartment I to the compartment 3 whose upper portion is usually filled with a gas, vapor or the like, in the lower deadcentre position 5 of the piston 5 which corresponds to point a of the diagram in Fig. 8, the valves 8 and I are closed. The piston now performs its upstroke and the material expands until the valve '0 is opened at b where the pressure in cylinder 4 has dropped to the lower pressure in compartment I. The valve 1 remains closed. While the piston moves from b to c, i. e. into its upper dead-centre position, material is drawn into the cylinder 4 from compartment I through valve 6. At 0 the piston is in its upper deadcentre position 5 The (outlet) valve 6 is closed and the (inlet) valve I remains closed. As the piston performs part of its downstroke, the charge in the cylinder 4 is now compressed to the pressure in compartment 3 and the (inlet) valve 1 opens at d, when this pressure has been attained. (Outlet) valve 6 remains closed and the material is now delivered to compartment 3 through (inlet) valve 1 under the pressure in compartment 3. At a the piston is again in its lower dead-centre position and a fresh cycle begins. The expansion curve w-b and its end at b are determined, among other factors, by the ratio of the initial volume of the charge and its final volume at b. By suitably selecting this ratio and by tapping the charge during the expansion period, the period bc, during which material is drawn in, can be varied. Similarly the beginning of the admission to the compartment 3, at

, d, may be varied, for instance by admitting gas from compartment 3. Preferably pipes such as IT and I8 (Fig. 7) are used for this purpose.

The last-described method may also be performed with the obvious modifications in four strokes, as shown in diagram Fig. 3.

I wish it to be understood that I do not desire to be limited to the exact details of construction shown and described for obvious modifications willoccur to a person skilled in the art.

I claim:

1. An apparatus for conveying solid or liquid material, to which a gas or vapor is admixed, comprising in combination, two compartments, two chambers between and separated from said compartments, said compartments being arranged on different levels, the bottoms of said chambers sloping in the direction from the upper to the lower compartment, means for continuously and alternately establishing and severing communication between said two chambers and between a compartment and one of said chambers, and separate means for changing the pressure in each chamber.

2. The process of conveying mixtures of solid and liquid material to which a gas or vapor is admixed and more especially crystal masses with adhering liquid, from a compartment under a pressure A to a compartment under a pressure B arranged at a lower level, which comprises the operation, in-a'continuous cycle, of the steps, one

ment under pressure B, interrupting the communication between said chamber and the compartments under pressure B, producing in said chamber a pressure other than B and approaching the pressure A by acting upon the gases and vapors contained in said chamber, establishing communication between said chamber and the compartment under pressure A and admitting another batch of material from the compartment under pressure A into said chamber.

3. In the method of claim 2 the step of varying the succession of pressures in, such manner that the diagram representing the variations of pressure in the intermediate chamber is a closed line resembling the steam diagram of a two-cycle operating steam engine.

rial from said chamber to slide into the compart- 4. In the method of claim 2 the step of varying the succession of pressures in such manner that the diagram representing the variations of pressure in the intermediate chamber is a closed line resembling the steam diagram of a four-cycle operating steam engine.

5. An apparatus for conveying solid or liquid material to which a gas or vapor is admixed, comprising in combination, two compartments, a chamber between said compartments, means for continuously and alternately establishing and interrupting communication between one or the other compartment and said chamber, metering means between one of said compartments and said chamber, and means for changing the pressure in said chamber and in said metering means.

6. An apparatus for conveying solid. or liquid material to which a gas or vapor is admixed, comprising in combination, two .compartments, a chamber between said compartments, means for continuously and alternately establishing and interrupting communication between one or the other compartment and said chamber, a conduit arranged for temporary communication with said chamber, means for changing the pressure in said chamber and means for changing the pressure in said conduit.

7. An apparatus for conveying solid or liquid material to which a gas or vapor is admixed, comprising in combination, two compartments, one situated at a higher level thanthe other, a chamber forming a passage between said compartments, positively controlled means in said passage for continuously and alternately establishing and interrupting communication between said passage and one or the other compartment, and means above said passage for changing the volume or said chamber.

8. An apparatus for conveying solid or liquid material to which a gas or vapor is admixed, comprising in combination, two compartments, one situated at a higher level than the other, a number of similar chambers forming a passage between said compartments, means in said passage for continuously and alternately establish-,

ing and interrupting communication between said passage and one or the other compartment and between any two of the said chambers, and means above said passage for changing the pressure in said chambers.

WILL HEINEN.

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