US2727630A - Centrifugal loading controls - Google Patents

Description

Dec. 20, 1955 J. HERTRICH CENTRIFUGAL LOADING CONTROLS 4 Sheets-Sheet 2 Filed Dec. 12, 1951 INVENTOR.

Josep/l lie/512k PM MW ATTORNEYS Dec. 20, 1955 J. HERTRICH 2,727,630

CENTRIFUGAL LOADING CONTROLS Filed Dec. 12, 1951 4 Sheets-Sheet 3 IN V EN TOR.

/00 [0390]! Her]?! (/1 United States Patent 2,721,630 CENTRIFUGAL LOADING coNTRoLs Joseph Hertrich, Hamilton, Ohio, assignor toThe Western States Machine Company, Hamilton, Ghio, a corpora fi of Utah Application DecemberlZ, 19.51,Sefial'N $261,258 351Claims. (61. 2111-68) This invention relates to new and improved loading control mechanisms useful especially for regulating the introduction .of charge materials into heavycyclical centrigal machines of the type .used in the manufacture and therefining of sugar. It is particularly valuable for either the automatic control or the completely automatic performance of centrifugal loading operations.

Inaccurate loading is a common and verycostly fault in sugar centrifugal work. The centrifugal baskets should be loaded to their full capacity in order to maintain high production, yet this often results in overloading and losses of charge material containing crystallized sugar into the channels provided for collecting impure syrup. Though less noticeably, losses and inefiicienc'ies result also from any considerable variations of the volume of charge material introduced into the basket in thesuccessive centrifugal cycles, for these variations affect the thickness of the basket charges and the effectiveness of the centrifugal purging, washing and drying actions applied to each charge.

The labor requirements for loading operations also present problems in existing practice. The work imposes strains upon centrifugal operators, and in order to maintain satisfactory results a high degree of skill and attentiveness as well as physical enduranceare needed.

It has been proposed heretofore to save labor by means of various automatic mechanisms which, in general, are adapted to initiate loading automatically, to hold a loading gate open at a set position as the basket becomes filled, and to close the gate either after a preset period of time or when the basket-charge has reached a certain final thickness. These known mechanisms are not able to keep basket charges uniform, especially in sugar centrifugal work. In that work the charge material undergoes changes of fluidity during the processing of -a givenbatch or run of massecuite or magma, by reason of temperature changes or continued crystallization or the settling of crystals from syrup, and no two batches or runs have quite the same flow qualities. If the loading period is timed, the flow rate of the material determines thecharge volume, rather thanthe control mechanism. If the control mechanism responds merely to the final charge thickness, the charges still vary because substantially more or less charge material enters the basket after this response, depending upon the fiuidity of the-material and the distance between the loading gate and the basket.

These problems, if not the complexity or unreliability of the mechanisms heretofore proposed, have resulted in continued reliance on manually controlled loading operations, both in sugar industries and in other fields of use of heavy cyclical centrifugal machines. For lack ofsatisfactory loading control mechanisms, among other things, industry has continued to lack a satisfactory completely automatic machine of this nature.

The principal object of this invention is to provideloading control mechanisms for heavy cyclical centrifugal machines or the like which accurately regulate the successive 2,727,630 rPatented Dec. 20, 1955 '2 loading operations and thus avoid important losses and ine'ific'iencies suffered in present practice.

Another 'o'bject'of the invention is to provide loading control mechanisms which enable the substantially'uniform charging of baskets in successive centrifugal cycles even though changes occur in the fluidity of the charge material, and in .the use :of'which -the distance between the loading gateand'the'centrifugal basket has a negligible influence.

Another object :of the invention is to provideloading controlm'echanisms which enable centrifugal loading o erations to'be performed safely under mechanical regulation while the baskets are being accelerated in speed, so that no time need beflost in loading by reason of the use of these mechanisms.

Still another object is to provide commerciallypracti'cal mechanisms which free the operators of centrifugal machines from the physical strains attendant toloa'cling operations, and which reduce or eliminate the influence of the operators attentiveness and skill upon the etliciency obtained .in centrifugal work.

.Afurther object of the-invention is to provide loading controlmechanisms which bring about savings of labor costs, as well as increased efficiency, in centrifugal operaticns; and, still further, to provide such loading control mechanisms whereby allthe steps incident to centrifugal loading operations can be performed automatically in a highly reliable and efficient manner.

A still further object .is to provide centrifugal loading control mechanisms which automatically take account of changes in the hydrostatic head or depth of chargematerial in asupply tanlcfrom which the material is delivered 'into centrifugal machines, sothat differences in flow rate which result from such changes will not objectionably influence the uniformity of loading operations.

Among other objects of this invention are: To provide .loading control mechanisms which can be applied to any existing heavy centrifugal installation with little mechanical alteration .of the installation; to provide such mechanisms which are useful for the controlled loading of many different types or grades of charge material, and under any desired process conditions; and to provide suchmechanisms which have simple and easily accessible adjustments for adapting the operation of the mechanism to the processing requirements of any material for which it may be used.

According to this invention the loading gate serving a centrifugal machine is provided with a power operated gate closing means, which preferably is a single gate operating motor, such as an air cylinder, serving both to open and to close the gate; the centrifugal is provided with a chargemeasuring device that is changed in its position or condition of actuation as the volume of a basket charge increases inthe course of a loading operation; and aprogressive automatic coordination of the operation of these elements is brought about by means of a control mechanism that responds progressively to charge induced movements of the measuring device and in turn actuates the gate closing meansprogressively so as to bring the gate from open position to progressive closing positions corresponding to progressive positions of the measuring device.

A mechanism of this character makes use of suitable control means adapted to be moved progressively in response to movements of the charge measuring device, together with actuating means for the gate motor that respond progressively to movements of such control means. The gate closing action of the motor can be controlled in definite correlation to the position of the measuring device by the provision of. further means for progressively biasing the motor actuatingmeans, or the control means to which it responds, to. a motor inactivating position in response to closing movements of the gate itself.

The invention further provides control mechanisms of the nature described which bring the loading gate to a pinched or largely closed position as the basket charge approaches a desired final volume, and which then act quickly to complete the closing of the gate by uninterrupted action of the gate motor.

In this way, the mechanism is able to determine quite accurately the final volume of the charge, for the loading gate moves to pinched position in definite relation to the building up of the charge, and the limited amount of material that can flow through the gate as it closes finally from the pinched position need not be enough to cause an objectionable deviation from the desired final charge volume. Rapid loading can also be assured, since the control mechanism can actuate the gate motor to open as well as to close the gate and can be set to cause any desired degree of gate opening at the outset of a loading operation and to hold the gate at this degree of opening until the basket charge reaches a desired thickness at which it will initiate the progressive gate closing action. This selectivity of the loading rate is important not only as a time saver but also to the usefulness of a given apparatus for a wide variety of charge materials.

The charge measuring device most conveniently used is a finger or charge feeler that bears against and rides over the inside face of the charge being formed in the rotating basket. The control mechanism can have a variety of forms and various means of interconnection with the other elements; among them, electrical, electro-pneumatic and direct mechanical connections. While a step by step action of this mechanism can be provided, the invention also provides progressively acting mechanisms having a continuing servomotor action that enhances the sensitivity and reliability of the loading control. In these, any movement of the charge feeler induced by an increase of the charge volume may position control elements so as to cause a gate closing action of the gate motor, and the resulting gate closing movement brings about a counteraction of the change of feeler position so as to keep the gate open, though closing gradually as the charge builds up, until at a desired charge volume the gate reaches a final degree of opening from which it is closed quickly to terminate the loading operation.

In any embodiments of the invention the movement of the charge measuring device to an active or charge feeling position may be coordinated with actuation of the gate motor to open the loading gate.

According to another feature of the invention, the control mechanisms are provided with simple and easily accessible means of adjustment by which they may be adapted to the processing needs of any charge material or go any centrifugal installation for which they may be use One such adjustment may be provided for setting the final gate opening, by which is meant the pinched or narrowly opened position from which the gate is closed completely to terminate a loading operation. This adustment permits easy correction of any tendency to overload or underload the centrifugal in handling a particular type of charge material.

Another adjustment may be provided for setting the final charge volume to be produced in each loading operation, this setting being selected according to the nature of the charge material to be treated and the treatment it is to receive in the centrifugal.

W Still another adjustment may be provided for setting the mitlal gate opening, i. e., the distance or width to which the gate is opened at the outset of each loading operation, so that any desired rate of loading may be obtained. Further, the mechanism may include an adjustment for the initial charge volume," i. e., the charge volume at which partial closing or pinching movement of the gate is to begin. This factor can be determined by the settings made for final charge volume and initial opening.

gate I The invention comprehends embodiments adapted for manual attendance, i. e., for the manual initiation of each loading operation followed by the automatic conduct and termination of the loading under the control of the mechanism, in which all the required control and adjustment functions may be integrated into a compact mechanical unit that can be mounted readily at the centrifugal machine with only a simple connection between it and a gate operating motor.

In other embodiments of the invention, which are suitable for either manual or automatic initiation of loading operations, an electrically operated motor device such as a torque motor may be employed for moving a charge feeler into working position, and this movement may bring about the actuation of the gate motor in gate opening direction. In such embodiments it is desirable to have the electrical parts located away from the vapors, dust, etc., commonly to be found at the curb of a centrifugal machine.

According to a particularly advantageous combination, a compact control in the nature of a servo-motor, comprising electrical, pneumatic and mechanical elements, is provided for mounting near to and in connection with the loading gate and the gate motor of a centrifugal installation, while another compact unit integrating the measuring and adjustment functions of the mechanism is mounted on or adjacent to the centrifugal curb in suitable connection with the charge feeler and the servo-motor control, so that upon actuation of that control to open the gate resulting gate and control movements will place the charge feeler in working position; while later movements of the feeler induced by the increasing charge in the centrifugal basket will act through the control to close the gate in the desired progressive manner.

According to a further feature of this invention, the action of the loading control mechanism is modified automatically in accordance with changes of the hydrostatic head or level of charge material awaiting delivery through the loading gate, so that variations of flow rate which result from such changes need not be observed by an operator nor compensated by manual adjustments of the mechanism in order to maintain highly efiicient loading operations at all times. While various devices may be employed in this combination, a preferred embodiment makes use of pressure responsive means connected with the loading control mechanism and with the tank holding the charge material, which respond to changes of the hydrostatic head of material in the tank and adjust the setting of the loading control proportionately so as to increase the initial gate opening as the level of material in the holding tank falls, and so as to decrease it upon a rise of that level.

Other objects, features and advantages of the invention will appear from the following detailed description and the accompanying drawings of illustrative embodiments thereof.

In the drawings:

Fig. 1 is a diagrammatic assembly view of a cyclical centrifugal installation provided with an automatic loading control mechanism according to a preferred embodiment of the invention;

Fig. 2 is a diagrammatic longitudinal cross-section of an air control valve used in the embodiment of Fig. 1;

Fig. 3 is an elementary wiring diagram suitable for the electrical elements of the same embodiment;

Fig. 4 is a diagrammatic assembly view of another embodiment of the invention.

Fig. 5 is a diagrammatic assembly view of a third embodiment of the invention adapted for the integrated control of functions of the loading control mechanism in a manually activated unit located at the curb of the centrifugal machine;

Fig. 6 is a vertical cross-section through part of the control mechanism of Fig. 5; and

Fig. 7 is a fragmentary plan view, partly in horizontal cross-section, showing parts of the control mechanism of the second embodiment combined witH- means-for rendering the loading gate inoperable'wlien a sliding cover element of the centrifugal curb is in closed position; and

Fig. 8 is a diagrammatic elevational view, partly in vertical cross-section, showing the combination of the first-mentioned embodiment with means for automatically modifying the action of the loading control mechanism in response to changes of the pressure head of charge material awaiting delivery into the centrifugal machine.

Referring first to Fig. 1, this diagram is a composite of elements shown in plan view at the right hand side of the figure and other elements shown in elevation at the left hand side of the figure. At the right hand side, 1 denotes a portion ofthe side wall of a filtering centrifugal basket of the type usedin t-he processing of'sugar.

A portion of an annular basket charge, say of sugar, or other granular solids, is indicated at 2. The inner surface of the complete charge is indicated at 2b, while broken line 2a indicates a position through which the charge surface progresses inward in the course'of a loading operation.

At the left hand side of Fig. 1, 3 is a portion of a tank holding charge material to be delivered into the centrifugal basket 1. The material flows-from this tank through loading spout 4 and thenceinto thebasket when a loading gate 5, of any suitable construction, is moved away from its position closing the spout outlet. Gate 5 is connected by suitable linkage, including link 6, arm 7, gate operating shaft 8 and arm 9, with the reciprocatory plunger of an air cylinder 10 which serves as a motor both for opening and for closing the loading gate.

It will be evident that when air under suitable pressure is admitted into the upper part of cylinder 10 through conduit 1'1, the arms 9 and 7' on shaft 8 are rocked counterclockwise so as to lift gate 5 to an open position at which charge material in tank 3 will flow under gravity into basket 1; while admission of the air pressure through conduit 12 into the lower end of cylinder 1t conduit 11 then being suitably vented, brings about a closing movement of the loading gate.

What has been described immediately above is well known in the art. It also is well: known that the opening of the loading gate should take place after the basket of the cooperating centrifugal has been emptied and brought to a low speed of rotation sufiicient to cause the formation of an even annular wall of the infiowing charge material under the centrifugal force imparted to it by the basket rotation. Further, it will be understood that the formation of a complete charge in the basket requires a considerable period of inflow of the charge material, say 10 to 30 seconds, more or less, depending upon the volume of the charge to be treated, the size and extent of opening of the loading gate, and the flow rate of the charge material.

' As the charge material flows into the basket, the annular charge being formed therein increases gradually in thickness until it reaches a final thickness corresponding to the desired charge volume, at which point 'theloading closed. This progressive building up of the charge is susceptible to measurement in various ways. A particularly simple yet efiective way of measuring it, as well known, is to use a charge feeler that slides on and is moved inward by the rotating inner surface of the increasing charge. Such a charge feeler is illustrated at 15 in Fig. 1. This feeler is carried by and swings with a shaft 16 which may be mounted by an suitable bearing and bracket arrangement on or adjacent to the usual stationary curb (not shown) of the centrifugal machine.

In combination with the elements just described, Fig. 1 shows a loading control mechanism comprising two coordinated assembly units 20 and 40 which are interconnected by suitable link means at 17. Unit 20 includes the feeler shaft 16 and charge feeler 15, and serves to integrate the charge measuring andadjustment functions of the control mechanism. Unit 40 includes a reciprocable support 41', here having the-form of'a control box mounted for rocking movementon a fixed pivot 42located in suitable relation to the gate operating mechanism. This support is connected for forward-and: back- .ward movements with opening and closing movements of the loading gate 5. For example, alink 18has a pivotal connection at 43 with support 40: and another pivotal connection at 44 with the gate operating arm 7 on shaft'8.'

The reciprocable support or control box 41 carries a gate motor control device'45, the nature of which issuitably adpated to that of the gate operating motor. In the embodiment shown, device 45 is an" air valve having a relatively fixed element or valve body 46fastened: to support 41 and a relatively movable element or valve plunger 47. The movable element is normally biased' by compression spring 48 to a gate opening position but is movable backward from that position, first to a gate inactivating position and then to a gate closing position at the backward limit of its. movement.

Various known forms of air valves are suitable for this purpose. The one shown, as seen in Fig. 2, has formed in valve body 46: a central port '50 for connection with a compressed air supply line 55; laterally offset ports 51 and 52 for connection, respectively, with the air conduits 11 and 12 of cylinder 10; and vent ports 53 and 54- near opposite ends of the valve body. The body has a long axial chamber 56 formed with five annular air passages communicating with the respective 'air ports, and the plunger 47 extends through this chamber and carries therein spaced sealing pistons 57' and 58. Piston 57 controls the air flow into and from conduit 11, and piston 58 controls the air flow into and from conduit 12. At the gate opening position of the valve, air entering port passes through port 51 into conduit 11, while conduit 12 is vented through communicating ports 52 and 54. At the deenergizing or gate inactivating position (an intermediate position of the plunger), pistons 57 and 58 seal off ports 51 and 52 and prevent any passage of air through the valve. At the gate closing position, air from line passes through ports 50 and 52 into conduit 12, while conduit 11 is vented through communicating ports 51 and 53.

The several operative positions of the motor control device or air valve 45 are determined by the positioning of a control member 60 which is arranged over the base of the reciprocable support 41 so as to be carried with the support in its forward and backward movements, yet is movable relative to the support in order to position the movable valve element. Member 60 in this embodiment has the form of a bar, a mid-portion of which, at its backward side, engages the forward end of the valve plunger 47.

The lower end of control member 60 projects downward from the support or control box 41 for pivotal con nection at 61 with one end of the interconnecting link 17. That link extends forward from unit 40 for pivotal connection, as at 19, with a lever arm 21 on the feeler shaft 16 of unit 20. The upper end of member bar 60 is arranged to be positioned by a motor device 62 which is fixed to the support 41. This motor device conveniently may be an electrically operated solenoid having a plunger 63 in position to thrust the bar forward when the solenoid is energized.

A tension spring 64 is fixed to a backward part of support 41 and to an upper part of member 60 so as to bias member 60 and valve 45 to gate closing position whenever the motor device 62 is deenergized. This spring is strong enough to overcome the force of the valve spring 48. Another tension spring 66 is fixed to a forward part of support 41 and to a lower part of control member .60, so as yieldably to connect member 60 and unit 20 for movements with support 41 in response to movements of the loading gate 5.

The control member 60 is held in a stable working position, relative to plungers 47 and 63 and tension springs 64 and 66, by means of a transverse slot 67 in the mid-portion of member 60, which slot engages over a pin 68 fixed to the free end of a reciprocable shaft 69. Shaft 69 fits slidably within a guide 70 fixed to the base of support 41 and also in a guide groove or slot 71 formed in a side flange of the support. The backward end of guide 70 engages the mid-portion of control member 60 at its forward side and keeps this member from moving forward out of working position. The control member, however, remains freely movable relative to the centralizing pin 68 for the automatic operation of the control mechanism.

The shaft 69 is made reciprocable and has its forward end connected with a manual operating lever 72 through suitable linkage 73, so that the control mechanism can be operated by hand to bring about opening and closing movements of the loading gate. A stable normal position of the shaft and pin 68 is maintained, notwithstanding vibrations to which the mechanism may be subjected in use, by means of a compression spring 74 which surrounds shaft 69 between the guides 70 and 71 and bears against collars 75 and 76 also surrounding this shaft. These collars in turn are seated against respective pins 77 and 78 fixed to the shaft 70 and 71, respectively. It results that a force sutficient to overcome the compression of spring 74 is necessary in order to slide shaft 69 either backward or forward in the guides. Such a force can be applied by rocking lever 72 in either direction about its fixed pivot 72a. When lever 72 is pushed backward, pin 78 thrusts collar 76 backward against the compression of spring 74, and the centralizing pin 68 thus can be moved backward until it has engaged the backward end of slot 67 and has moved member 60 and plunger 47 against the tension of spring 66 to either the gate inactivating position or the gate closing position, as desired. On the other hand, if control member 60 and plunger 47 are already at gate closing position, pin 68 can be moved forward so as to dispose them at gate inactivating or gate opening position, by pulling forward on lever 72. In this case, spring 74 is compressed by action of pin 77 on collar 75, and pin 68 acts on the forward end of slot 67 to position the control member and air valve.

In the idle position of shaft 69 and lever 72, control member 60 can move backward and forward relative to pin 68 and also can undergo rocking movements about this pin. The extent of its rocking movements relative to support 41 may be limited by suitable means such as stop pins 80 and 81 fixed to a lower portion of the support for engagement with a lower part of member 60.

The functions embodied in unit 40 may now be described further:

If solenoid 62 is deenergized, its plunger 63 exerts no pressure on member 60, and spring 64 then holds member 60 and air valve 45 in gate closing position; i. e., compressed air from line 55 passes through the valve into conduit 12, and conduit 11 is vented through the valve, so that cylinder moves or holds the loading gate to closed position.

When solenoid 62 is energized, plunger 63 thrusts the upper end of member 60 forward against the tension of spring 64, and if the lower end of this member is then being held in a forward position by spring 66 or link 17, the control member and air valve are disposed in gate opening position. The compressed air from line 55 now passes into conduit 11, and conduit 12 is vented, so that cylinder 10 starts moving the loading gate to open position. As the gate moves open, its operating arm 7 acts through link 18 to rock support 41 forward on pivot 42. Control member 60 and link 17 move forward with the support, thus allowing solenoid 62 to keep member 60 and valve 45 in gate opening position, unless and until a limit or restriction is imposed against their for- 69 adjacent to the guides ward movement. Thus the gate could be moved and held as far open as possible, with air pressure continuing to be applied through conduit 11, until it were desired to close the loading gate, at which point control member 60 and air valve 45 could be disposed in gate closing position by deenergizing solenoid 62, thereby causing spring 64 to move them to that position, or by thrusting backward on hand lever 72.

On the other hand, the operating positions of the control mechanism can also be determined by the positioning of the lower end of control member 60: If, while the gate is opening, a resistance is applied through link 17 to limit the forward movement of member 60 with support 41, a further increment of forward movement of the support causes a relative backward movement of the lower end of member 60 to dispose this member and the air valve in gate inactivating position. The air valve then seals otf both of conduits 11 and 12, so that the air cylinder 10 holds the loading gate in whatever position it occupied at the moment of the shifting of member 60.

Moreover, if the lower end of member 60 is now given a backward movement by action transmitted through link 17, it will dispose the air valve in gate closing position and cause the air cylinder 10 to start closing movement of the gate. But a corresponding backward movement of support 41, which then results through gate arm 7 and link 18, will again dispose member 60 and the air valve in gate inactivating position, unless a further backward movement of link 17 and the lower end of member 60 has occurred meanwhile through further action on link 17 It will be evident, therefore, that the opening of the loading gate can be brought about automatically or by remote control through the energization of motor device 62; that the resulting forward movement of unit 40 produces a corresponding forward movement of link 17 which, through lever arm 21 and shaft 16 of unit 20, will serve for the outward movement of feeler finger 15 to a working position in desired relation to basket wall 1, as the loading gate moves open; that by limiting the forward movement of link 17 the extent of the initial gate opening can be predetermined, the gate motor being inactivated to hold the gate at the selected extent or width of full opening when the limit is reached; and that the closing movement of the gate can be brought about progressively through progressive backward movement of the lower end of member 60, in direct proportion to that movement. Further, it will be evident that the progressive inward movement of charge feeler 15, as induced by a progressively increasing charge in the centrifugal basket 1, can act through shaft 16, lever arm 21 and link 17 to cause progressive backward movement of the lower end of control member 60 and, in this way, to cause closing movements of the loading gate proportionate to the increasing thickness of the basket charge; i. e., proportionate to the inward movement of the charge measuring device 15.

The ratio of increments of closing movement of gate 5 to increments of inward movement of feeler 15 is dependent upon lever ratios existing in the connections between these elements. By suitable selection or adjustment of these ratios the loading gate may be caused to close in any desired relation to the inward movement of the feeler. For example, lever arm 21 may be formed with a series of spaced openings 22, any of which may be chosen to receive the pivot pin 19 on the forward end of link 17 so as to select a desired ratio for the movements of the feeler and the gate.

Referring more particularly to the construction of unit 20, it will be seen from Fig. 1 that lever arm 21 is not fixed directly to feeler shaft 16 but is connected for rotation with this shaft and the feeler through an underlying rotary member 23 and still another underlying lever arm 24 which is fixed to shaft 16. Lever arm 24 11 circuit through contacts LTl. After expiration of the time interval set on the timer mechanism, the timer will close contacts LT2 in a circuit between solenoid 62 and line L1, thus energizing the solenoid to cause the opening of the loading gate and other coordinated movements of the loading control mechanism as described above.

The operation of the first embodiment may be explained further as follows: At all stages of the operating cycle of the centrifugal machine, except the loading stage, the loading gate is in closed position, the charge feeler 15 rests at an extreme inward position out of contact with any charge in the basket, and the control member 60 and air valve 45 are in gate closing position, solenoid 62 being deenergized. The basket 1 being empty and having been brought to a low speed suitable for loading, solenoid 62 is then energized in any of the ways above mentioned.

Of course, in cases of emergency or abnormal conditions, a manually controlled loading operation can be brought about easily by manipulation of lever '72. But automatically controlled loading is normally desired; so solenoid 62 is energized, and the mechanism then proceeds to bring about a complete and precisely controlled loading operation, quite automatically.

First, member 60 and the air valve 45 are shifted to gate opening position by the action of solenoid 62, and air cylinder proceeds to move the gate in opening direction. At the same time, unit 40 and link 17 are moved forward and unit 20 is moved counter-clockwise about the axis of shaft 16 so as to move the charge feeler outward into working position, to close limit switch 31, which holds closed the energizing circuit of solenoid 62, and finally, when the gate is at the desired degree of full or initial opening, to engage abutment 23c with stop element 29 so that a slight additional forward movement of support 41 will dispose member 60 and air valve 45 at gate inactivating position.

The opening of the gate, of course, admits charge material into the basket, and this inflowing material builds up into an annular charge of progressively increasing thickness. When the inner surface of the increasing charge has reached the feeler, say at line 2a in Fig. l, feeler 15 begins to be moved inward. As it moves inward, unit is turned clockwise about the axis of shaft 16, and control member 60 is thrust backward at its lower end by link 17 to shift the air valve from gate inactivating position to gate closing position. The loading gate 5 then starts to close under the force of air pressure admitted through conduit 12 into cylinder 10.

As the gate closes, however, it produces a backward movement of support 41 and valve 45 to counteract the charge induced movement of link 17 and member 60, thus biasing member 60 and the air valve inactivating position. Further inward movement of the feeler, induced by further building up of the charge, causes a fur ther movement of the control member in gate closing direction, to be counteracted in turn by the further gate closing movement, until the charge has reached approximately the desired final thickness and the gate 5 has a pinched position from which it can be closed quickly without allowing an objectionable surplus of charge material to enter the basket.

At that moment, the limit switch cam 23d moves clear of limit switch arm 32, and contacts LS1 then open to deenergize solenoid 62 and cause control member 60 and air valve 45 to be disposed and held in gate closing position. The gate then moves quickly to its completely closed position. At the same time, finger 15 is moved further inward to a position where it will not obstruct the rotation of the charged basket as the centrifugal machine proceeds on its operating cycle.

The embodiment of the invention shown in Figs. 4 and 7 has several features in common with that of Fig. 1.

It differs, however, in the'form, arrangement and operation of parts of the controls and in that the loading gate: is closed step by step in response to charge-induced move ments of a charge measuring device, instead of in continuous response thereto as in Fig. 1. Further, this device is moved to working position by its own motor. Only electrical connections exist between a charge feeler assembly 20A, adjacent the curb C of the centrifugal, and a control assembly 40A which is connected mechanically with the loading gate. The loading gate has an open position, a pinched position and a closed position, and in closing it is moved rapidly from open to pinched position after most of the charge has been formed and. is again moved rapidly from pinched position to closed position when the charge is at the desired final volume.

In Fig. 4 the arrangement of the loading spout 4a, the loading gate 5a and the gate operating mechanism, including link 6a, arm 7a, shaft 8a, arm 9a and air cylinder 10a, is similar to the arrangement of Fig. 1. As illustrated, however, downward movement of the air cylinder piston and arm 9a serves to close the loading gate, and upward movement thereof serves to open the gate; so the gate opening air line 11a is connected with the lower end of the cylinder and the gate closing air line 12a is connected with its upper end.

These air lines extend from ports of an air control valve 45a which is mounted on a slidable support 41a forming part of assembly 40A. Valve 45a is connected with a source of compressed air through air line a. It has a plunger 47a normally biased to gate opening position by a compression spring 4811, and in construction and operation it may be like the air valve described in connection with Fig. 1.

The operating positions of the air valve are again governed by the positioning of a movable control member a which is arranged over the face of support 41a so as to be movable with this support yet to undergo relative movements by which an abutment 61a at one side of member 60a will dispose the valve elements in gate opening, gate inactivating or gate closing position. The support also carries a solenoid 62a in position to engage the upper end of member 60a and thrust this member away from the valve body when energized. A tension spring 64a extending between the upper part of member 60a and an anchor on support 41a serves to bias the control member and valve plunger toward gate closing position. A second tension spring 66a, anchored to the support and to the lower part of member 60a, acts in a direction opposite to spring 64a and normally holds a stop pin 80a on said lower part against an abutment 81a fixed to the movable slide.

It will be evident that when solenoid 62a is energized member 60a may be thrust away from the valve body against the tension of spring 64a so as to dispose the valve in gate opening position, air pressure then passing through line 11a; while when deenergized solenoid 62a allows spring 64a to dispose the control member and valve body in gate closing position, in which air pressure passes through line 12a into the lower end of cylinder 10a. On the other hand, when solenoid 62a is energized, member 60a and the air valve nevertheless may be disposed in gate inactivating position or gate closing position by forcing the lower part of the control member toward the valve body against the tension of spring 66a.

Furthermore, any desired position of the control member and air valve may be established by the manual operation of a hand lever 70a which is fulcrumed at 71a and is connected with the mid-portion of control mmber 60a through link 73a, arm 74a pivoted at 75a to the slidable support, and link 76a. This manual operating mechanism serves the same functions as the mechanism connected with lever 72 in the embodiment of Fig. 1.

The support 41a is mounted for sliding movement in a fixed housing 42a by means of a rod 43a which carries the support and extends slidably through bearings 44a and 44b on opposite side walls of the housing. The forand closing. movements-of the ,loading r gate a produce proportional .forwardsand backward :sliding movements, respectively, .ofpsupportdla. These movements are utilized for positioning the .controlmember and air valve asfollows:

The lower-end 63a of member .6011 moves forward with support 41a, asthe-loading gate opens, in a path in which it will engage anabutment 65a on-an adjustably positioned arm 67a. Theforrward endof this arm slidably engages a guide 6.8a fixed tontheshousing. Its backward end is pivotedto an arm 69a which-in turn is pivoted to the fixed housing at 7.01:. An adjustable stop or set screw 71a is mounted tonthe backward side wall of the housing so as to engage .armw69a and determine the working position of the-abutment 65a, this .position being yieldably maintained by a tension-spring 72a'which is anchored to arm 67a and the housing :structure so :as to keep arm 69a in engagement withzthe "stop element. The abutment 65a thus constitutes aneadjustable means for determining the initial opening of the loading gate. When solenoid 62a is energized to dispose control member 60a and air valve 45a in gate opening :position, the loading gate opens and at the .same time-.support 41a :moves forward. These movements continue until end-63a of the control member has engaged'the preset :abutment65a, whereupon the control member and air valve are disposed at gate inactivating position. The loading gate then ceases its opening movement, at a position determined by the setting of abutment65a.

in the initial gate closing operation, which follows when solenoid 62a is deenergized, any desired pinched" position of the loadingga-te isestablished, through backward movement of the slide support 41a, by means of an arm 77a which presents an abutment 78a in the path of movement of the upper end 79a of control member 60a. Arm 77a is pivoted at its backward end to an arm 82a which in turn is fulcrumed on fixed pivot 70a. An adjustable stop or set screw 83a, mounted on the housing side wall, and a tension spring 843a extending between arm 77a and the housing structure, serve to position abutment 78a in the manner described with reference to abut ment 65a. In this instance, however, spring 841a tends to swing arm 77a upwardly and out of the path of the control member, and a solenoid 85a is mounted on the housing in position to counteract the spring action and hold abutment 78a in that path when this solenoid is energized. Accordingly, the energization of solenoid 35a in conjunction with opening movement of the loading gate will cause abutment 78a to be disposed in the path of backward movement of the control member; and when gate closing action occurs, the concomitant backward movement of support 41a and member 6th; brings the upper end of member 60a into. engagement with abutment 78a, whereupon a further increment of gate closing movement shifts the air valve 45 relative to member 60a so as to dispose these elements at gate inactivating position. Thus the final opening or pinched position of the loading gate is determined by the adjustable setting of abutment 78a.

Further, when it is time to complete the closing of the loading gate this may be accomplished automatically by deenergizing solenoid 85a (solenoid 62a having been previously deenergized). Spring 84a thereupon shifts arm 77a and abutment 78a out of engagement with the control member and allows spring 64a to dispose this member and the air valve at gate closing position.

The conditions of actuation of the solenoids of control assembly 40A are determined by the charge feeler assembly 20A. Two limit switches 21a and 31in are associated with that assembly; switch 21a being connected in a control circuit leading to solenoid 62a, and the other limit switch being in a circuit to solenoid 35a. The limit switches :have aarms 22a -.and -32a, -respectively, which normally hold their respective-eontacts open but are .moved to close the respective solenoid circuits as described below. V

AssemblyltlA includes. a charge feeleriia adjustably mounted on-a shaft 16a which extends vertically through two spaced bearings 'lob and'lfic. One bearing is fixed to the top of curb C and the other is fixed above it to a bracket orhousing 1851. 'A torque 'motor 17a is mounted on a support "19:; extending from this housing. The torque motorshaft 1'7 b is keyedto a coupling 164 which is also keyed to the upper end of feeler shaft 16a, so that the charge feeler and the torque motor move together. When the torque motor is energized it acts in a counterclockwisedirection, as viewed from the top of Fig.4, to move feeler 15a outward into working position. The torque then exerted, however, 'is so limited that the pressure of charge material against the feeler, as a charge builds up in the centrifugal basket 1, is able readily to overcome this torque and move the feeler inward.

Below bearing -16c two control elements 24a and 25a are mounted on shaft 16a. The first is keyed to the shaft opposite limit switch arm 32a and comprises a radially protruding cam 24b for operation of this switch-arm and upwardly projecting abutment 24a. The second is loose on the shaft,-above element 24a, and comprises a radially protruding cam 25b for operation of limit switch arm 22a. Element 25a also has a radial arm 25c in which a stop element or set screw/ 25d is threaded for engagement with the abutment 240 on element 24a.

A pin 25s on arm 25c serves as the anchor-for one end of a tension spring 26a, the other end of which is anchored to the frame 18a so that the feeler shaft assembly is biased clockwise by this spring. Whenever the torque motor is inactive, spring 26 moves the assembly to disposefeeler 15a and the switch cams 24b and 25b in an idle position.

As seen in Fig. 7, the extreme inward or idle position of the feeler is determined by a stop element 27:: adjustably fixed in housing so as to engage a side of camldb at any desired limit of. its clockwise movement. The initial outward or working .position of the feeler is determined similarly by a stop element 23:: which is adjustably fixed in another part of housing i8a so as to engage a side of cam 25b at any desired limit of the counterclockwise movement of the feeler shaft assembiy.

it will now be evident that an automatic centrifugal loading operation may be started, in the use of this second embodiment, merely by energizing torque motor 17a. The motor then turns the feeler shaft assembly counterclockwise against spring 26a until the feeler reaches an initial working position determined by stop element 28a and in the course of this movement, cam 24b acts first upon arm 32a to close limit switch 311/, and shortly afterward cam 25]) acts upon arm 22!! to close limit switch 21a. The solenoids 525a and 62a thus are energized so as to urge arm 77a and abutment 78a toward their working position and to thrust forward the upper end of control member 68a. Air valve 45a now admits compressed air into the lower end of cylinder Etta; loading gate 5a starts opening movement; and arm 77a moves to its working position.

When the charge feeler has arrived at the desired outward position its movement is stopped by stop element 28a, but the motor 17!: continues to be energized and to keep the two limit switches closed.

When the loading gate has reached the predetermined open position its motion is stopped by the action of abutment 65a as already described.

Meanwhile, charge material flowing into the centrifugal basket forms therein an annular charge wall of progressively increasing thickness; and after the inner surface of this will reaches the feeler 15a, it moves the feeler inward as the charge increases, thus turning the feeler shaft assembly clockwise against the motor torque. At an inward feeler position determined by the setting of adjustable stop element 25d, cam 25b releases switch arm 22a, whereupon the contacts of limit switch 21a are opened and solenoid 62a is deenergized. The control member 60a and air valve 45a are thus disposed at gate closing position, and compressed air flows into the upper end of cylinder a to move the loading gate in closing direction. As the gate so moves the support 41a slides backward, and at a desired pinched position of the gate abutment 78a stops the upper end of the control memher so as to dispose this member and the air valve at gate inactivating position.

The gate now stays at the desired pinched position, allowing only a relatively small stream of charge material to enter the basket, until the charge induced movement of feeler a has caused cam 24b to release switch arm 32a. At that moment the contacts of limit switch 31a open, whereupon solenoid 85a is deenergized, spring 84a lifts abutment 78a out of the path of control member 600, and spring 64a moves the control member again to gate closing position. The loading gate then moves quickly to its completely closed position, and a complete charge of the desired volume is obtained in the centrifugal basket.

The position of the feeler 15a at that moment, which determines the final charge thickness in the basket, is adjusted by means of the set screw 33 which holds the hub of the feeler at any desired position on shaft 16a.

After the completion of the charging operation torque motor 17a preferably is deenergized so that spring 26a will move the feeler shaft assembly farther clockwise to the idle position determined by stop element 27a, at which position feeler 15a is spaced inward from the inner surface of the rotating basket charge.

A third embodiment of this invention will now be described with reference to Figs. 5 and 6 of the drawings. In this embodiment the centrifugal basket 1 on shaft 1A is associated with a charge feeler 15, and a unified control mechanism located at curb C is connected mechanically for movements with the feeler and with the operating mechanism of the loading gate. The operation of this loading control mechanism is initiated manually, whereupon the mechanism proceeds to control and complete a loading operation in substantially the manner described in connection with Fig. 1.

As seen in Fig. 6, feeler '15 is mounted on feeler shaft 100 which extends vertically through spaced bearings 101 and 102 in opposite ends of a supporting tube 103 which depends from a hub 104 fixed over the curb top. Hub 104 is fixed to base plate 105. The upper end 100a of shaft 100 carries a control member 110 which is fixed to the shaft and has two arms 111 and 112 extending horizontally over the base plate in the form of a fork or yoke which terminates in spaced, oppositely facing rounded ends 111a and 112a. These rounded yoke ends bear against the opposite ends of a valve plunger 114 which is the movable element of an air control valve 115 similar to valve 45 of the first embodiment. The body of valve 115 is mounted on a movable support 130 which overlies base plate 105 and embraces hub 104 so as to be reciprocable thereon about the axis of shaft 100.

The air valve 115 has a compressed air supply line 116 and air lines 117 and 118 which lead respectively to opposite ends of air cylinder 119. The piston of this air cylinder is connected pivotally at 120 with arm 121 fixed to a gate operating shaft 122, this shaft being connected with a loading gate in any suitable manner such as that of Fig. 1 or that of Fig. 4. It sufiices here to state that when control member 110 is shifted counterclockwise relative to support 130, it disposes valve plunger 114 at gate opening position so as to admit compressed air from line 116 through line 117 into the backward end of cylinder 119, thereby causing the loading gate to open; and when the control member and valve body shift relatively in the opposite direction, the valve is disposed at gate closing position and compressed air passes through 16 line 118 into the forward end of cylinder 119, thereby closing the loading gate.

Opening and closing movements of the loading gate bring about concomitant movements of the control mechanism through suitable mechanical connections between the movable support and a control cam 124 which is fixed to turn with the gate operating shaft 122. For ease of illustration, these connections are shown as if they existed in a single plane, although the connection to support 130 typically would extend horizontally from this support and the cam 124 typically would move in a vertical plane. Support 130 has a spherical coupling at 131 with a rod 132 which is suitably connected for movement to and fro with movements of a vertical connecting rod 133. This rod in turn is connected through an adjustable coupling 134 and a spring coupling 135 to one arm 136 of a lever which is fulcrumed on a fixed pivot 137 between its arms, and which carries on its other arm 138 a cam roller 139 held against the face of cam 124. A spring 140 yieldably holds the cam roller against the cam.

In addition to part of coupling 131 the movable support 130 carries nearby an abutment 142 in position to engage a fixed yet adjustable stop element 143 at a desired limit of clockwise movement of the support.

The movable control member 110 is integral or joined with a hand lever which extends forward from the feeler shaft for convenient operation by an attendant of the centrifugal machine. An abutment 152 is fixed to this lever in position to engage a relatively fixed yet adjustable stop 154 at a desired limit of counterclockwise movement of control member with support 130.

The operation of this third embodiment of the invention is as follows:

As shown in full lines in Fig. 5, the charge feeler 15 is in an idle or extreme inward position, the loading gate (not shown) is closed, and cam roller 139 rests on a lower face 124:! of cam 124.

In order to initiate a loading operation, the attendant of the machine grasps hand lever 150 and easily moves it counterclockwise, thereby disposing the yoke-like control member and valve plunger 114 at gate opening position so that compressed air passes through line 117 and moves the air cylinder to open the loading gate. As the gate moves open, cam roller 139 and arm 138 are lifted by the rising face 124!) of cam 124, and through the linkage extending to support 130 this movable support is turned proportionately about the axis of hub 104. The support thus follows the hand lever, and as long as the hand lever continues to be moved ahead of the support, the gate continues to open. If the hand lever movement is stopped, the gate stops opening at a corresponding position; and if the hand lever movement is reversed, the gate closes correspondingly.

Normally, however, the hand lever is moved counterclockwise until it reaches a predetermined limiting position at which the desired initial gate opening is obtained, and this movement also turns shaft 100 so as to dispose feeler 15 in a desired initial working position as illustrated by broken lines in Fig. 5. The initial gate opening and the initial feeler position are predetermined and kept uniform in successive loading operations by the setting of stop element 154, since abutment 152 engages this stop element after a predetermined hand lever movement, whereupon a slight further movement of the gate and support 130 causes yoke end 112a to dispose the air valve 115 at gate inactivating position.

The open loading gate is now delivering charge material into basket 1, and when the thickness of the growing charge reaches line a, the charge surface begins moving feeler 15 inward. As the feeler moves inward it turns shaft 100 and control member 110 in clockwise direction and thus shifts the control member and air valve plunger to gate closing position, air pressure then passing through line 118 into the gate closing end of cylinder 119. The gate now starts closing, but as it moves in closing direcaazz qs 21? tion a correspondjng, backward (clockwise) movement ,of support I 130 is produced through the action of cam ,124

,..and elements 131 tol inclusive. T his backward movement'in turndisposesthecontrol member and air valve at.gate inactivating position,-for thevalveplungerll l is easily: slidable in the ,valve body and the valve elements will shiftto that position. before they can transmit hrough member ll-llen'ough force to overcome-thefriction of "shaft100 in bearings-101, and 1632. Meanwhile, however, thefeeler, is stillybeing moved inwardrso itfacts continuously to bias thecontrol member andair valveto gate closing position, while. beinghcounteracted continually by further gate, closing movements which bias these elements to, gate inactivating position. .It results ihatthe closing .movement of the loading gateis broughtabout in .continuous response tofthecharge induced movement offthe charge feeler,jand a definite relaticnto that movement which is determinedbythe operating connections between gate ,shaftlZZ and support 130.

As already explained, however, the charge finally reaches adesired thickness at which the loading should end .quickly without further progressive action of the control mechanism. This point isdetermined by the setting ,of stop element 143. When abutmentMZ engages this stop element the support 130 cannot move farther in clockwise direction, and :any ,further inward movement .ofteeler then disposes control member 110 definitely at gate ,ciosingposition and the gate quickly completes .i ts closing movement.

.It will be understood that directmechanical connection could beapplied instead ,ofa cam between arm 138 ,and lanai-m on, gate shaft 122. Inth'at event'thespring coupling135 wouldpermit overtravel in theilinkage between, themo vabie, support 130 andih'e gate mechanism.

'Apam connection -ot"t theftypeillustrated maybe advarittageous, however; in that any desired relationshipbetweeh the travel of the charge feeler 15 fandthe travel ofithe loading gate can be obtained by suitable formation ot the cam used at 124. in this way the action oft heloading control mechanism can be easily modified was to con fform with special requirements of any particnlar typeof charge material to be loaded and treated in the centrifugal machine. i r

. Byadjustingthe positionof stop element 154,'the initial adjustments and for progressive manner of operation .quitesirnilar to those provided for in the embodiment of Pig. 1. I v I A furthenfeature or thisinvention.consrsts'm a comi bination which, prevents the opening of theloading gate through automatic operation of 'theloadin'g control'mech- .anisrn unless a movable cover for the centrifugal curb .top isin openposition. Further, an inadvertent closing ,ofthc curb-cover in'thecourse of arloading operation will interrupt the'loading by-closingthe'loading gate. To this end the. movablecurb cover is provided with meanswhich to hold this mechanismingate closingposition whenever the curbcover is closed, and which release the cooperating parts for normal operation when the curb cover is .open.

Such-a combination is illustrated in Figs. 4 and7,as applied in the, second embodiment above described. The curb top at 86 has a central opening87 around'basket spindle 1A, and a coverele'merit 88 is sli dablelabout a ,fixed pivot 89 so as to ,open and close the top opening.

. l L cooperate with ,parts of the loadmg control mechanism =13 ,Ascqntrol rod 90 is pivoted to.cover S8 at 91, this rod extending forward from its pivotin slidable engagementwith a guidebracket 92 When cover 38 is closed, as .seen in Fig. 7, the forward iendportion of rod 9% lies in the path of turning movement of a tail piece 93 extending radially from control element 24a. The relative locations of rod 99 and tailpiece '93 aresuch that therodis retracted from thepa th ofthe tail piece when cover 88'is open;but when the cover is closed rod 90 blocks counterclockwise movement of the feeler shaft assembly, thus preventingactuation of the loading gate through cam 25b and limit switch 21a. Even though the torque, motor is energized, the feeler shaft assembly cannot"move to active position as long asthef closed curb cover holds rod 90 across the path of tail piece J93; so solenoid 62a is never energized'andtheautomatic control mechanism never opens thejloading gate 'as long as the curb cover is closed. Althoughopeningof thecurb cover removes rod 90 from thefpath'fof tailpiece93,jit

willbe evident that end 94 of 'tliisirdfi will engagethe tail piece and thrust the feeler shat assembly clockwise to, its idle position if the curb coveris closedwhile the loading control mechanism is active.

.According to a further 'feature ofthi's invention, the

' ,loading control mechanism is provided with structures which act automatically to vary the "eXte'ritof opening of the loadinggate, in difierent loading operations, .so as .,to icornpensate for changes in helevel or pressure head of the supply of charge material from Whi' h lt e centrifugal machine is loadedinthesesoperations. Such changesinfiuence the velocity ofdlowthroughtheg gate orifice, and these ,further structures are adapted 'to controhthegate opening 'so,that the charge material will'flow at 'approximately the same volumetric rate over long perio'dsof centrifugal operation, notwithstanding major changesoflevelin the holdingtank serving the centrifuggal machine. To achieve this result, the heightiof the gate; opening obtained at any posi tion of the charge feeler isrna 'de smaller for loading operations occurring when the charge material flows outuncler a higher level and pressure head, than it is when thelevel of the charge material'is reduced.

"There are variousways of obtainingthis "function with the newlo'ajding control mechanisms. 7 For example,suitable Estopfelements in embodiments already described jca'n be-turned progressively, by hand or by any suitable progressive or step-by-step mechanism, at a rate correlated to the rate of change of the level of charge matejrial'in'the holding tank. 'On theother hand, a p'ref erred -manner of obtaining this function is illustrated in Fig. '8

0f the "drawings, which shows pa'rtsof the embodiment tiffi'gsj l to 53in combination with a level-compensating mechanism which responds 'directly to the hydrostatic pressure of material in the holding tank 3 and adjusts proportionately a connectinglinkage that governs ;the

"ratio df the travel-of "loading gate 5 tothe travel of'the chargefeeler 15 (Fig. 1).

"Fig. '8 shows in outline the movable control .box or {support- '41 with control member 60 projecting frornthis btjx for-connection through link 17 with the feeler shaft ssembly (if unit 20 ,(Fig. 1). The loading gate 5 "is againioper'ated"through link-6, arm 7 and gate operating shaft BL Gate movements are again transmitted to ,sup-

port 41 through link 18 pivotedatone end, at 43, to,

"the scene box; but instead of being fixed to arm ,7 "as at "flinFig. 1, 'theo tl'ier end of this link is coupled for movement with'the gateoperating mechanism through a variable-positioning device 200 which serves to vary antorria tically the effective length of'the connecting link, as"f01lo"ws: a

The forward 'end'o'f'link 18 is pivotally connected at goiter the head 203 of a plunger204 which is reciproca- "ble within a hollow body member 205, The .plunger headis guidedin passage 206 of the body member, while thestem "of .the (plunger extends through body ,wall 207 into a piston chamber 208 where it carries piston 209 on its inner end. The body member 205 is keyed to gate operating shaft 8 so that it moves in the same sense as arm 7, thus moving link 13 and support 41 in proportion to the movement of gate 5.

The lever ratio existing at any movement, however, depends upon the position of head 203 in passage 206, and this position is determined according to the pressure head of material in tank 3 in the following manner:

A compression spring 210 within chamber 208 biases piston 209 toward shaft 8, thus tending to shorten the lever arm between gate and support 41 under a force which varies with the degree of compression of the spring. A compressed air line 212 enters the base of the piston chamber to apply therein a fluid pressure counterbalancing the spring pressure. This air line extends from an air chamber 216 which is fixed over an opening 217 in tank 3 and is separated from charge material in this tank by a flexible diaphragm 218. A restricted orifice 219 enters chamber 216 from a compressed air line 220 containing air under a pressure at least equal to the maximum pressure asserted on diaphragm 218 by material in the tank. Another restricted orifice 222 is provided for venting pressure from chamber 216. The air fiow through these orifices is controlled by needle valves 223 and 224, respectively, both of which are carried on the outer side of a floating valve member 225. The inner side of this valve member bears against a stem 226 on diaphragm 218, being thrust against this stem by a compression spring 227 which has enough strength to open or close either needle valve.

It results that the air pressure in chamber 216, hence the pressure transmitted through line 212 into piston chamher 208, is always in balance with the pressure exerted by charge material against the diaphragm. When tank 3 is filled with charge material the outward pressure of this material acts through stem 226 to rock member 225 against spring 227 so as to open needle valve 223 and hold valve 224 closed, thus allowing the air pressure to counterbalance the material pressure. The diaphragm then moves inward until both needle valves are closed. As material is withdrawn from tank 3, however, an overpressure developing in chamber 216 will move the diaphragm and stem 226 inward, whereupon spring 227 rocks member 225 inward so as to keep valve 223 closed yet to open valve 224, until a pressure balance again closes both needle valves.

Thus the air pressure acting on piston 209 always corresponds to the pressure of charge material in tank 3, and this air pressure positions the plunger head 203 and link 18 at a corresponding distance from the axis of the gate operating shaft 208. Accordingly, when the charge material is at a high level, link 18 operates on a larger lever arm than when the level of charge material is lower, and the gate opening produced by the loading control mechanism is therefor smaller in the case of a high level and larger in the case of a lower level. In this way the level compensating mechanism can so vary the connecting linkage in the loading control mechanism that a substantially uniform rate of flow of charge material through the loading gate will be maintained in all loading operations, notwithstanding the accompanying changes of level in the holding tank.

It will be understood that the foregoing detailed description and-the accompanying drawings are intended to exing device positionable by charge material in the basket, means for energizing the gate motor including independently movable control elements having gate opening, gate closing and motor deenergizing relative positions, means for positioning one of said elements according to positions of said gate and means moved independently of said gate for positioning another of said elements according to positions of said device, means for concomitantly activating said charge measuring device and biasing said elements to gate opening position, said first mentioned positioning means being responsive to charge induced movements of said device to bias said elements to gate closing position, and said independent positioning means being moved progressively with closing movements of the gate so as to counteract the last recited means and bias said elements to motor deenergizing position so that progressive closing positions of the gate are determined by positions of said device.

2. In a loading control mechanism for a cyclical centrifugal installation including a rotary basket, a loading gate for delivering charge material into the basket and a gate operating motor, the combination of a charge measuring device positionable by charge material in the basket, gate motor energizing means including independently movable control elements having gate opening, gate closing and motor deenergizing relative positions, a shiftable member controlling the position of one of said elements, means for concomitantly activating said measuring device and positioning said member and said one element so as to dispose said elements in gate opening position, means responsive to charge induced movements of said device for shifting said member and said one element so as to dispose said elements in gate closing position, and means moved independently of said device in response to closing movement of the gate for displacing another of said elements relative to said one element so as to counteract said shifting means and dispose saidelernents in said motor deenergizin g position.

3. In a loading control mechanism for a cyclical centrifugal installation including a rotary basket, a loading gate for delivering charge material into the basket and a gate operating motor, the combination of a charge measuring device positionable by charge material in the basket, gate motor energizing means including independently movable control elements having gate opening, gate closing and motor deenergizing relative positions, a shiftable member controlling the position of one of said elements, means for concomitantly activating said measuring device and positioning said member and said one element so as to dispose said elements in gate opening position, means responsive to charge induced movements of said device for shifting said member and said one element so as to dispose said elements in gate closing position, means moved independently of said device in response to closing movement of the gate for displacing another of said elements relative to said one element so as to counteract said I shifting means and dispose said elements in said motor til deenergizing position, and means for rendering said independently moved means ineffective at a predetermined pinched position of the closing gate.

4. In a loading control mechanism for a cyclical centrifugal installation including a rotary basket, a loading gate for delivering charge material into the basket and a gate operating motor, the combination of a charge feeler movable when in working position by an increasing charge in the basket, gate motor energizing means including independently movable control elements having gate opening, gate closing and motor deenergizing relative positions, a movable support carrying one of said elements, a control member carried with but shiftable relative to said support to position another of said elements, means for displacing said support and said one element in proportion to movement of the loading gate, concomitantly operative means respectively for shifting said control member and said other element relative to said support to dispose said eletpfo etsai 'd, elements in, gate closing' position, the actionl'of ,5 sa d displacing means upon agate, closing movement ,serving to counteract the last, recited means so as; to bias-said elements to motor deenergizing positionv pendingQa further charge induced movement ofthe feeler. 1 f5. In ,a loading control mechanism for a cyclical centrifugal installation including ,a rotary basket, a loading ,gat e t for ,Idelivering, charge material, into the ;.basket and ialgate operating motor, the combination of a ,rnonable support; a gate motor energizer on said support comprisling rsla tively fixediand relatively movableelements havgate opening, gate closing and deenergizing posi'tions, :atmembercarried bvbut'shi fztable relative to said support position saidmovabletelements, ca charge feelerrnovj ble when in reworking rpositionliby an increasing charge pose said energizer in deenergizing position, and-means for adjustingthe ,position, of said limit. device so :as to seleet any: of various degrees of initial gate opening.

,7. -lnta loading control mechanism as describedin claim 5, means includinga limit device operative at; a t-predetermined tinward position of the feeler to render ineffective 1. said repositioning means 1 and position said, member 5 to hold-said energizer in gate closing v position.

8- In a -loading control mechanism as i-deseribed in claim 5, means including a limit device operative gat a predetermined inward-position'of the feeler to'render inefieotive said repositioning means and position d member to hold said energizer-in, gate closing po s n, and ime'ans for adjusting the 'relative tposi-tions of said limitwdevice-andt the feeler-seas to, selectzany ofn-vanious -final vthicknesses for the basketcharge.

movable control'element, a charge feelermovable inward,

=When in working position by an'increasing charge in the basket, means for displacing said support with move- -ments-of the-loading gate, means'including amoto'r device onlsaidisupport for shifting said member to dispose; said xelement in gate opening position, means Ffor interconnecting said member and said feeler so that; displacement t of said support andsaidrnember withgate openingmovement moveszthe feeler outward to working position, and so that tan inward -feeler r movement will shift saidi memhen; to dispose said element in t gate closing .position, 1 .and

{ nuthe basket, ;;means [for r displacing said support with amt-ansresp asis uto a i nlacemen s said-supp tw {gate closing ianovemen't {to bias said member so {as to tdisp .rs dt l cnt n qei fg ins nosi 'o tperid ns .itnr'then inward movement "of. .the feeler,

'Q lLQIn alloading control mechanis'm as .described.in .claim 10,1{means'1ineluding a limit switchwandavswitch operator moved with said interconnectingymeans for ingactivaf g'fsaid-motordevice and positioning-said memlbenstofl old said control element in, gate 'closingfposition l at avpre'determined inwardflposition of -.the feelermove- 715 fselect any 'clesired final opening for the lo2i'di1 igv gate.

fi13, A loading control mechanism .as described in claim ll, and means for adjustingthe relative positions of said switch operator and saidgfeeler so, asto select any desired final thicknesslfor the 'ba'sket charge.

14.: In a loading coritrolimechanism as described, in claim 11, an abutment member moved with-said interconnecting means, a relatively fixed stop engaged by said abutment ,memberjafter a predetermined displacement of said support with gate opening movement, to position 2 5 said member and thereby ,said control elements in .de-

jenergizing position and means for adjusting jtheposition of said stop sojas' to ,select, any desired.maximumv open- 7 ing for the L load ng gate.

"15.- In a floalding control vmechanism for a cyclical centr 'tuga ins a l t on in lud ng a a y' s allar tan f r 1 h ld g c r em erial h v g a lo n t fforfis ngts p m ri l rijd r gr v yifi w int zthe iba lse an ai ff i Cl sin t etg t a h r m as iaaidwie n 5 'o i bl 'jbya ch rge ng in baske ntrol meansfmove' jd progressively in response tof charge fe 0 ient o S i devi c uat g mea fo i sate 1 1 s m n pro e si ely" sponsiv t mov mer t lo ts r ntr mea m an pr ssi ly L isp rs i o filo's n m ve em of th .,g=j 1f j i tiva 4 iii .s id gategel s ns'mean gso a tq e the gate pr g 1S7 e yj'a e fdins ]pmgr sdvemQ emen f sa did v 'e yan ea op ra p o s i ely t c an t e v QL rposi ion fio h ad n s e nd ,,said m a u in "device inj'correspondence to changes in the'head and dischargefrlatejof materialin. said tank.

f 16. Ina loading"controllmeehanism 'for a jcyclical tcentrif ug'al finstallati on including a "rotary basket, a large 3. 3. r. hold n a m t a ng a loadi "ga for'delivering such materialunder gravity flow into'j'the basket, vand agate operating tair cylin der, the combinai -9JIni a' loading control mechanism astdescribedtin i o yo aimo ab supno x ink to cronne i a d s p- "-portfo'r'rnovementlwith the-gate, an air valve on said snpportfforl controlling said cylinder comprising amov- "able "elementfhavin'gjgateopening gate closing and gate inactivatingpositions,lajjmember carriedlwith but shiftfable'r'elative" tosaid support to position the movable valve em n a. harg f e movab e wa wh in wor ing po'sition b'y an jincre'a'sing charge in the basket, ,a "moto'r'deviceon said support for shifting saidmemberto disPDSe'said VaIVejinjgate opening position, meanstor interconnecting said jniemjber and said feeler so that dis- "p eme 'sa uppor fan sa e b thsate openingmoveme'nt moves theffeeler outward to working position, and so that an inward "feelenmofvement .jwill shift 'saidmember to dispose said valve 1 in gate closing 'positiom means responsive to displacement of said' 'support with gate closing movement to"biasj.said'member soas to dispose said valvein gate inactivating position pending fu'rtherinward movement of the'feeler,' whereby m fthe gate is closed progressively indefinite relationship fto positions of .thefteeler, and means responsive to changes of the 'pre'ssure offchargematerial in said tankfm' adjustin'g saidlinkage sofas tochangethe relative working' positions v the gate and the jfeeler.

' l7. I Injra loading control mechanism for a cyclical cen trifugal installation including a rotary basket, a loading gate for delivering charge material into the basket and a gate operating fluid pressure cylinder, the combination of a movable support, a fluid valve on said support for energizing said cylinder comprising relatively fixed and relatively movable elements having gate opening, gate closing and deenergizing positions, a member carried by but shiftable relative to said support to position the movable valve element, a charge feeler movable when in working position by an increasing charge in the basket, means for displacing said support with movements of the gate, a manual operating device having connections with said feeler and with said member for moving the feeler outward to working position and simultaneously shifting said member to dispose said valve in gate opening position, said connections being responsive to inward movements of said feeler to shift said member so as to dispose said valve in gate closing position.

18. In a loading control mechanism for a cyclical centrifugal installation including a rotary basket, a loading gate for delivering charge material into the basket and a gate operating fluid pressure cylinder, the combination of a movable support, a fluid valve on said support for energizing said cylinder comprising a relatively fixed and relatively movable elements having gate opening, gate closing and deenergizing positions, a member carried by but shiftable relative to said support to position the movable valve element, means normally biasing said member toward a position disposing said valve in gate closing position, a charge feeler movable when in working position by an increasing charge in the basket, means for displacing said support with movements of the gate, a yielding motor connected with said feeler for moving it outward to working position, a motor device on said support for shifting said member against said biasing means so as to dispose said valve in gate opening position, switch means activated as the feeler moves outward for energizing said motor device, a limit device operative upon a predetermined displacement of said support with gate opening movement to shift said member so as to dispose said valve in deenergizing position, said switch means being responsive to a predetermined inward movement of said feeler to deenergize said motor device, limit means operative upon a predetermined displacement of said support with gate closing movement to shift said member so as to dispose said valve in deenergizing position, and means responsive to a further inward movement of the feeler to inactivate said limit means.

19. In a loading control mechanism for a cyclical centrifugal installation, a support adapted to be mounted at the installation for movement to and fro on its mounting, an air valve carried by the support comprising relatively fixed and relatively movable elements having gate opening, gate closing and gate inactivating positions, a control member carried with and shiftable relative to said support to position the movable valve element, the support having means by which to connect it for forward and backward movements with opening and closing movements of a loading gate, and means carried with said support and adapted to cooperate with a movable basket charge feeler for positioning said control member to establish said valve positions.

' claim 19, said positioning means including a motor device 24 on said support operative when energized to dispose said member and said valve in gate opening position.

22. A loading control mechanism as described in claim 19, said positioning means including a relatively fixed stop acting at a limiting forward position of said support to shift said member so as to dispose it and said valve in gate inactivating position.

23. In a loading control mechanism for a cyclical centrifugal installation including a rotary centrifugal basket, a loading gate, a gate operating motor and a charge feeler movable by an increasing basket charge, a motor con trol device, a reciprocable support carrying said device and adapted to be connected for forward and backward movements with opening and closing movements of the gate, a control member carried with and shiftable relative to said support for disposing said control device in gate opening, gate inactivating and gate closing positions, means for moving said member and device to gate opening position, means including a limit element to be located in a relatively fixed position for moving said member and device from gate opening to gate inactivating position after a predetermined forward movement of said support, means actuatable by charge induced movement of the feeler to dispose said member and device in gate closing position, said member having connections responsive to backward movement of said support to shift said member and device to gate inactivating position, and means including another limit element to be located in a relatively fixed position for holding said member and device to gate closing position after a predetermined movement of the feeler.

24. A loading control mechanism as described in claim 23, and means for adjusting the working position of the first-mentioned limit element so as to select any desired maximum opening for the loading gate.

25. A loading control mechanism as described in claim 23, and means for adjusting the relative positions of the last-mentioned means and the feeler so as to select any desired final thickness for the basket charge.

26. A loading control mechanism as described in claim 23, and means for adjusting the relative positions of said actuatable means and the feeler so as to select any desired ratio of feeler movement to gate closing movement.

27. A loading control mechanism as described in claim 23, and means for adjusting the working positions of the last-mentioned means so as to select any desired final opening for the loading gate.

28. In a loading control mechanism for a cyclical centrifugal installation or the like, a reciprocable support, linkage to connect it for forward and backward movements with opening and closing movements of a loading gate, an air valve mounted on the support having outlets to be connected with opposite ends of a gate operating air cylinder and having a valve element biased to a gate opening position but movable backward to a gate inactivating position and thence to a gate closing position, a control bar shiftable over said support and controlling the positions of said valve element, an intermediate portion of said bar engaging said valve element, a reciprocable motor device on said support to position a portion of said control bar at one side of said valve element, and link means to position a portion of said bar at the opposite side of said valve element according to the position of a charge measuring device.

29. A loading control mechanism as described in claim 28, and a charge measuring device comprising a feeler finger movable outward to a working position and thence inward by an increasing volume of a charge to be measured, a rotatable shaft carrying the feeler, and a lever arm on said shaft connected for movements therewith and with said link means.

30. A loading control mechanism as described in claim 29, having a limit switch adjacent said shaft for controlling said motor device and an element mounted on and movable with said shaft to operate said limit switch.

31. A loading control mechanism as described in claim 30, said limit switch operator being loosely mounted on said shaft and having a lever arm adjacent the first-mentioned lever arm, and yieldable interconnecting means for said lever arms including means for adjusting their relative positions.

32. A loading control mechanism as described in claim 30, said lever arm and said limit switch operator each being loosely mounted on said shaft, a lever arm on said operator adjacent the first-mentioned lever arm, yieldable interconnecting means for said lever arms including means for adjusting their relative position, another lever arm carried by said shaft adjacent said limit switch operator, and yieldable interconnecting means for said other lever arm and said limit switch operator including means for adjusting their relative position.

33. A loading control mechanism as described in claim 30, comprising an abutment on said limit switch operator, and a relatively fixed stop for engaging said abutment to stop movement of said link means with said support after a predetermined forward movement of said support.

34. In a loading control mechanism for a cyclical centrifugal installation including a rotary basket, a loading gate for delivering charge material into the basket and a gate operating motor, the combination of a charge measuring device positionable by charge material in the basket, independently movable cooperating control elements having an inactive relative position and a gate closing relative position for energizing said motor to close said gate, means responsive to charge induced movement of said device for moving one of said elements so as to dispose said elements in said gate closing position, and means moved independently of said device in response to closing movement of said gate for moving another of said elements so as to dispose said elements in said inactive position, so that the closing movement of said gate induced by said motor energizing elements occurs progressively in accordance with the progressive building up of a charge in said basket.

35 In a loading control mechanism for a cyclical centrifugal installation including a rotary basket, a loading gate for delivering charge material into the basket and a gate operating motor, the combination of a charge measuring device positionable by charge material in the basket, independently movable cooperating control elements having an inactive relative position and a gate closing relative position for energizing said motor to close said gate, means responsive to charge induced movement of said device for moving one of said elements so as to dispose said elements in said gate closing position, and means rnoved independently of said device in response to closing movement of said gate for moving another of said elements so as to dispose said elements in said inactive position, so that the closing movement of said gate induced by said motor energizing elements occurs progressively in accordance with the progressive building up of a charge in said basket, said mechanism including means operative upon movement of said device beyond a predetermined position at which the basket charge is nearly at a desired final volume to render said independently moved means ineffective so as to maintain said elements in gate closing position and thus cause quick movement of the gate from a pinched yet still open position to a completely closed position.

References Cited in the file of this patent UNITED STATES PATENTS 1,157,979 Fasting Oct. 26, 1915 1,961,893 Wadman et al. June 5, 1934 2,037,655 Roberts Apr. 14, 1936 2,090,373 Neuman Aug. 17, 1937 2,130,864 Steps Sept. 20, 1938 2,328,394 Neuman Aug. 31, 1943 2,376,304 Anderson May 15, 1945

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