US1598301A - Evaporator plant - Google Patents

Description

Aug. 31, 1926. 1,598,301

J. MUGLER v EVAPORATOR PLANT I Filed Feb. 8, 1926 2 Sheets-Sheet 1 1 NVEN TOR.

444 ATTORNEY.

Aug. 31, 1.926.

J. MUGLER EVAPORATOR PLANT Filed Feb. 8. 1926 2 Sheets-Sheet 2 INVENTOR. BY /7 Patented Aug. 31, 1926.

UNITED STATES JULIUS MUGLER, 0F BERLIN, GERMANY.

EVAPORATOR PLANT.

Application filed. February 8, 1926, Serial No. 86,746, and. in Germany January 80, 1925.

My invention relates to evaporators and more especially to multiple-stage evaporators, wherein the evaporating'steam or vapor and thematerial under evaporation passes from one unit to another. Such evaporators are, for instance, used in sugar factories, where the clarified sugar juice is'concentrated by gradual evaporation in socalled sugar pans to a sirup of a certain density.

The last or ultimate evaporator in the series is usually connected to a condenser in which a vacuum is maintained.

In modern evaporator plants which work with high steam pressure, the condenser is omitted, the steam in that case being conducted to other steam consumers, after it has done its work in the evaporators. In such evaporator plants, because of variations in the steam consumption, the pressure in the last evaporator will either rise above or drop below the desired point with the result that the final density of the material under evaporation varies, and when the pressure rises too high in the last evaporator, steam must be blown off.

The object of the present invention is to prevent the ill effects of varying steam pressure in such plants by the use of automatically operating regulators so as to thereby insure a product of uniform density. 'In accordance with this invention, there is provided in addition to the regular evaporators an additional unit, which may operate either as another evaporator or merely as a part through which the material under treatment may pass there being provided overflow pipes or by-pass connections for the vapors between the various units which overflow pipes are equipped with automatic regulators so that steam of higher pressure of one unit may be supplied to the next succeedin units, a further regulator being provided etween the additional unit and other steam consuming devices. In this way the efficiency of the plant can be kept constant irrespective of any variations in the steam consumption, so that at all times a uniform product is obtained. However, where the amount 01" the material to be evaporated and the density are not always the same, further .means are required to keep the evaporation constant so as to prevent various de rees in the density of the final product. 0 this end, I provide in the steam or vapor pipes special lve, which autom t c lly r gulates the steam or vapor by means of an automatic density regulator controlled by the density of the evaporated material.

In the annexed drawing, in which I have diagrammatically shown, by way of illustration, my invention as applied to a sugar plant, Fig. 1 shows the arrangement of the evaporator units and the location of the automatic regulators, Fig. 2 shows an. ar rangement for use when an amount and the density of the material under' treatment vary, Fig. 3 is a detail view of the automatic regulator used in connection with the evaporator units.

According to Fig. 1, the plant comprises the well-known evaporator units 1, 2 and 3, adapted to receive the material to be treated, which in the selected example is clarified sugar juice. Fresh steam is supplied to the heating chamber 0 of the evaporator 1. The hot vapors arising from the sugar juice in evaporator 1 pass through the pipe 5 into the heating chamber C of the evaporator 2, while the hot vapors arising from the juice in evaporator 2 pass through the pipe 6.int0 the heating chamber C of evaporator 3. Surplus steam or ivapors pass from the;

respectively to other steam or heat consuming apparatus (not shown). In addition to the evaporators 1, 2 and 3 there is provided a further unit 4, to the heating chamber-C? of which hot vapors may be supplied at certain times from evaporator 3 through pipe 7. The pi e 7 is provided with an automatic regu ator 17 and a similar regulator 16 is provided in the steam or vapor discharge pipe 8 of the unit 4.

The operation of this plant is as follows: The evaporated sugar juice is successively pumped through the pipes 12, 13, 14 from one evaporator to the next and finall into the additional unit 4, from which it 1s discharged through the pipe 15 connected to a pump (not shown). 7

If, because of too small a withdrawal of steam or vapors by consumers from the pipes 9, 10 and 11, the pressure in the eva orator 3 rises to above a predetermined point the automatic regulator 17 is caused by the rise of pressure to operate to admit steam or vapors to the heating chamber of the unit 4, which heretofore acted only as a passage for the evaporated sugar juice but now also begins to do work as an evaporator, so that evaporators through the pipes 9, 10 and 11 the total efliciency ofthe plant and thereby also the density of the final product are kept constant.

Should the pressure in the unit 4 also rise above a predetermined point, due to further lessened steam or vapor consumption through the pipes 9, 10 and 11, the automatic regulator 16, like the regulator 17 will be actuated by the excess pressure to let steam or vapors escape from the unit 4 either to a consumer, or a condenser. in case the temperature of the unit 4 is so low that the steam or vapor can not be utilized any further. The amount of steam or vapor in that case, however, will be only a fraction of the steam or vapor wasted in an evaporator plant of the usual construction, in which the additional unit for making use of the surplus vapors is lacking.

Similar automatic regulators 19 and 20 like those shown at 16 and 17 are provided in the by-pass connections 19 connecting the pipes 9, 10 and 11 in Fig. 1. These latter regulators are provided to permit surplus steam or va or of a unit of a higher stage to be supplied to the unit of a lower or succeeding stage, in case the steam or vapor consumption for other steam or vapor consuming devices should decrease while that of the next succeeding stage increases.

Assuming, for instance, that the steam consumption through the pipe 10 connected with the evaporator 2 decreases while at the same time, though not in the same degree, the consumption through the pipe 11 of evaporator 3 increases, the automatic regulator 20 and under certain conditions also the automatic regulator 19 will be caused by the higher pressure to operate to admit the surplus steam or vapor directly to the evaporator of the next lower stage, from which a greater amount of steam or vapor is drawn to supply other steam or vapor consuming devices. In this way, there will always be automatically produced a balance between the several evaporators so that even with varying steam or vapor consumptions the total etticiency of the plant will remain the same with the result that a final product of ever uniform density is obtained. As a matter of course. also the steam supply pipe to the first evaporator 1, is equipped with an automatic regulator 18 similar to those shown at 16, 17, 19 and 20.

A difl'erent arrangement is shown in Fig. 2, wherein are shown only three evaporator units 21, 22, 23 which are connected by the pipes 24 and 25 in such a way, that the hot vapors escaping from unit 21 are used to produce evaporation in unit 22, while the hot vapors from unit 22 heat the unit 23. In pipe 25 is provided a throttle 26 which is controlled by density regulator 28 provided in the'discharge pipe 27 for the evaporated material. Said density regulator is so designed that as the density. of the material decreases it causes the throttle 26 to open automatically, whereas, if the density increases. the throttle 26 closes so that in the first instance a greater amount of vapors passes into the unit 23, while in the other instance the vapor supply isthrottled. It is self-evident that a similar control can also be used in connection with the other evaporator units, or, if as in Fig. 1 an additional evaporator unit is used, in connection with the latter.

In Fig. 3 is shown in detail one type of automatic regulator which may be used in the arrangement according to Fig. 1.

Reference character 19 designates the connection between conduits 9 and 10. Flow of vapor or steam through this connection is controlled by a valve 50 operated by a servomotor 46 which is in turn operated by a pilot valve 33, 34, which is in turn operated by 'a relay R which relay is responsive to changes of pressure in conduit 19 ahead of valve 50. Changes of pressure in conduit 19 are transmitted through tube 51 and act upon a bellows 36 which is connected to a lever 52 through the intermediary of a pin 37. Lever 52 carries at one end a battling member 38 which is positioned over an opening 41 in a conduit 41 which connects with the pilot valve housing. Lever 52 is pivoted at 39 and is acted upon by a spring 40, the force of which is opposed to the pressure of conduit 19* transmitted to bellows diaphragm 36.

The pilot valve is supplied with fluid under pressure by means of conduit 43. This conduit supplies fluid both to the servomotor and to the relay. The supply to the relay takes place through a branch conduit 43 which contains a restriction 42. The fluid in flowing to the relay flows through a chamber 30 one side of which is formed by a diaphragm 31 which is connected to the pilot valve 33, 34. Fluid pressure acts in chamber 30 and is opposed by spring 54. The pilot valve 33, 34 affords connection with the servomotor 46 through conduit 45 with either supply conduit 44 which is connected to conduit 43 or a discharge conduit 55.

The operation of the regulator is as follows:

Assume that the pressure decreases in conduit 19. Lever 52 is then rocked to restrict outflow through opening 41. This causes a rise of pressure in chamber 30 which moves diaphragm 31 to the right and connects conduit 45 with discharge conduit 55. The pressure of fluid on the upper side of piston 47 is then released and due to the weight 49 which acts upon valve 50, piston 47 moves upwardly and valve 50 closes. The pressure is thus returned to normal.

Assume, on the other hand, that the 'pressure increases in conduit 19. This causes a rise of pressure force against bellows 36 4 which moves-lever 52 so that bafliing member 38 allows .a greater outflow of fluid through opening 41 and from conduit 41. Due to the restriction 42 this causes a drop of pressure in chamber 30 which results in a movement of diaphragm 31 to the left and movement of pilot valve 33., 34 to the left whereby conduit is connected with conduit 44 and pressure fluid is supplied to servomotor 45 causing a downward movement of piston 47 whichresults in an opening of valve 50-, thus returning the pressure to normal. It is thus seen that the valve 50 is so operated that the pressure in conduit 19 in front of the same and therefore the pressure in conduit 9 is maintained constant. Of course, other types of regulators may be used, and likewise, there may be modifications in the eneral arrangement of parts without any departure from the essence of the invention.

I claim: 1. In an evaporator plant, the combination with a plurality of evaporator units, of an additional unit, and automatically operated means enabling said additional unit to act either as an evaporator or merely as a discharge vessel for the evaporated product. .2. In an evaporator plant, the combination with a plurality of evaporator units, of an additional unit, a conduit for conducting vapor from the ultimate unit of the plurality to the additional unit, a valve to control flow through said conduit and mechanism responsive to pressure of steam in said ultimate unit for controlling said valve and operating to maintain constant the pressure in said ultimate unit.

3. In an evaporator plant,'in combination; a conduit system, an evaporator unit in said conduit system connected between a conduit of relatively high pressureand a conduit of relatively low pressure, a connec-' tion extending between said conduit of relatively high pressure and said conduit of relatively low pressure parallel to said evaporator, an automatic valve in said connection and pressure responsive mechanism for operating said valve to maintain a constant pressure in said conduit of relatively high pressure.

4. In an evaporator plant, iii-combination, a conduit system including a plurality of conduits adapted to carry steam of diiferent pressures and to supply steam to steam consumers, evaporator units coupled be tween said conduits, connections extending between said conduits and serving as bypass connections for said evaporator units, and valves in said connections operated by pressure of vapor in front of .said valves and acting to maintain the operating pres sure constant.

5.111 an evaporator, in combination, 4 a conduit system including a plurality of conduits adapted to carry steam of difi'erent pressures and to supply steam to steam consumers, evaporator units coupled between said conduits, connections extending between said conduits and serving as by-pass connections forsaid evaporator units, valves in said connections operated lay-pressure of vapor in front of said valves and acting to maintain the operating pressure constant, an additional evaporator unit, and automatically o erated regulating means enabling said additional unit to act either as an evaporator or merely as a discharge vessel for the evaporating product.

In testimony whereof I afiix my signature.

- {JULIUS MUGLER.

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