US2565689A - Sequential control system fok soot - Google Patents

Description

Aug. 28, 1951 c. L. HowsE 2,565,689

SEQUENTIAL CONTROL SYSTEM FOR SOOT BLOWERS Filed April 21, 1949 6 Sheets-Sheet 1 Aug. 28, 1951 c. l.. HowsE 2,565,689

SEQUENTIAL CONTROL SYSTEM FOR SOOT BLOWERS.

Il! l Irfan-Algra Aug. 2s, 1951 L. HOWS'E f 2,565,689

SEQUENTIAL CONTROL SYSTEM FOR SOOT BLOWERS Filed April 21, 1949 Sheets-Sheet 5 .A E. 9 JNVENTOR. v (QZ/"ijs HOM/5e.

. Aug. 28, 1951 v c. 1 HowsE 2,565,689

sEQUENTAL CONTROL SYSTEM FoR vso'oT' BLowERs Filed April 21, 1949 6 sheets-sheet 4 vxce Allg. 28, C. L. HOWSE SEQUENTIAL CONTROL SYSTEM FOR SOOT BLOWERS Filed April 2l, 1949 6 Sheets-Sheet 5 Ad I M41 .L LJ..

l INVENToR. (2y/"Z725 Han/5e- 7/ El. E..

Aug. 28,A 1951 2,565,689

C. L. HOWSE SEQUENTIAL CONTROL SYSTEM FOR SOOT. BLOWERS Filed April 2l, 1949 `6 Sheets-Sheet 6 INVENTOR.

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BY *El M/f/q Patented ug. 28, 1951 SEQUENTIAL CONTROL SYSTEM FOR SOOT lBLOWERS Curtis L. Howse, Spartanburg, S. C., assignor to Diamond Power Specialty Corporation, Detroit, Mich., a corporation of Michigan Application April 21, 1949, Serial No. 88,854

29 Claims.

The present invention relates to systems and mechanisms forY the control of uid actuated apparatus; having particular utility in connection with the control of soot blowers and analogous cleaning devices of the type incorporating blowing elements for projecting a cleaning agent against surfaces or objects to be cleaned. Soot blower units, particularly as used for the cleaning of large boilers, are commonly arranged either to rotate or to rotate and move longitudinally, and the present system is adapted to control the time of blowing and all of the operative movements of a plurality of such movable soot blowers in such manner that the blowers may be made to function automatically, in predetermined sequence.

An important object of the present invention is to provide an improved control system of the indicated character which is adapted to regulate the action of a plurality of blower heads of different types and operating characteristics.

Another object is to provide such a control system which employs air as the actuating fluid for controlling the action of the soot blowers or other controlled elements, and which incorporates an improved and simplied master control mechanism adapted to be arranged at a control station remote from the controlled blowing devices, the master control mechanism permitting an operator to vary or interrupt the sequence of operations of the controlled devices at will, to change the operating cycle of the system.

Another object is to provide such a control system of greatly simplified character which requires only a single conduit from the control station to each controlled device.

Still another object is to provide an improved control system of the indicated character which is so arranged as to indicate at all times the blowing sequence or sequence of operation of the controlled devices, both while they are operating and after the operating cycle is concluded, at which latter time the system shows the operating sequence of the preceding cycle.

Another object of the invention is to provide such a system adapted to control a plurality of blowing units which differ from one another in construction, operating characteristics and in the blowing media employed as well as in blowing pressures. For example, the system may be used to control some blowers which utilize air as the cleaning agent and others which utilize steam, while the blowers utilizing air may operate at different pressures, and the duration of blowing and the pattern and nature of movement of mov- (Cl. (S-97) 2 able blowers incorporated in the system may vary widely.

A further object is to incorporate in such a system improved means for preventing the operation of blowers utilizing steam until condensate in the steam lines has had an opportunity to drain.

Other objects and advantages of the invention will become apparent upon consideration of the present disclosure in its entirety.

In the drawings:

Figure 1 is a schematic diagram of a control system incorporating principles of the present invention;

Figure 2 is a front elevational view of the control panel of a central control mechanism also incorporating features of the present invention;

Figure 3 is a horizontal sectional View taken substantially on the line 3--3 of Figure 2 and looking in the direction of the arrows;

Figure 4 is a fragmentary rear elevational view taken as indicated by the arrow 4 of Figure 5;

Figure 5 is a side elevational view of the panel and associated mechanism, taken as indicated by the line and arrows 5-5 of Figure 2;

Figure 6 is an enlarged fragmentary elevational View of the portion enclosed within the dotted circle 6 of Figure 4;

Figure '7 is a fragmentary elevational View taken substantially as indicated by the line and arrows 1 1 of Figure 6;

Figure 8 is an enlarged fragmentary rear elevational View of the carrier assembly and associated parts for actuating the panel control valves;

Figure 9 is a sectional elevational view taken substantially on the line 9 9 of Figure 8, and looking in the direction of the arrows;

Figure l0 is an enlarged fragmentary elevational view of the start-stop valve and associated parts;

Figure 11 is a sectional elevational View taken substantially on the line Il-H of Figure 10, and looking in the direction of the arrows;

Figure l2 is a somewhat diagrammatic sectional plan view taken substantially on the line |2-I2 of Figure l1, and looking in the direction of the arrows;

Figure 13 is a diagrammatic view of motor control valving means employed in connection with the control of certain rotary types of soot blowers adapted to be incorporated in a system arranged in accordance with the present invention, certain of the parts being shown out of substantially on the line Iii-I6 of Figure 5, and

looking in the direction of the arrows.

Referring now to the drawings, Figure l shows schematically the arrangement of the principal components of a system adapted to control the operation of a plurality of soot blowers of different types. The details of construction of the blower units themselves form no part of my present invention, but it is assumed for purposes of illustration that all of the blowers are of a movable type, either rotary, reciprocating or rotary and reciprocating, and as previously indicated various types may be incorporated in and controlled Vby the system. Suitable blowers are shown, for example, in Patents Nos. 1,899,733, 2,126,683, 1,644,286v and in De Mart patent application Serial No. 766,183 filed August 5, 1947. For purposes of the present disclosure, it will be assumed that each blower, regardless of type, is provided with a pressure-controlled driving motor which is air-operated, although it will be understood' that other types of pressure-controlled driving motors might be used, as for example, electric motors with pressure switches.

The action of the entire system is supervised from a control station which may be, and nornia-ily is; located at a'point remote from all of the blowers. The mechanism at the control stationis mounted on a control panel 20 and supporting frame 22. The panel 20 is centrally provided with: a vertical slot 24-behind and in alignment with which a carrier 26 is adapted to travel. A- guiding rib portion 25 on thecarrier projects slidably into the slot. A knob 28 attached to the rib 25 projects forwardly from the front face of the panel, while the block 26 travels behind the panel and is laterally slotted at 21A and slidably irterttedl with a guide rail 21 supported behind the slot 24 by the frame 22. The rail 2l may be a relatively' flat strip and positioned to serve as a baffle` preventing vision through the slot, as best shown in Figure 3. The-carrier block is normally urged upwardly by a counterweight 30 which also actsasfa piston andl which is vertically slidable in a1 cylinder 32 supported as by bracket means 34 behind the panel and in parallel relation to the slot 24. A flexible'wire 35 is attached at one end tothe block 26 and at the other end to the piston weight 3l) and its intermediate portion is trained over a pulley 33 journaled in appropriate position near the top ofV the assembly as in the bracket means 38. The cylinder 32 may be substantially closed at one" or both ends, only a predetermined orifice being left to control the rate of air flow, thereby forcing the piston and cylinder assembly to serve as a dashpot to control the rate of movement of the block 26.

The block 26 carries a transverse plate 40 to the outer vertical edges of which a pair of rearwardly extending hinge plates 42, 45 are pivoted forv swinging movement about hinge pins 44, 41. A pair of headed screws 46, 48 project outwardly from opposite sides of the block through enlarged holes (undesignatecl) in the plates 42, 45. The" holes are large enough so that the screws do not interfere with swinging movement of the plates within their intended range, but the head of each screw limits outward movement of the plate through which it extends, and a compression spring 5|, 52 on each screw beneath the plate urges the plate outwardly. Outward movement of the hinge plates is limited as by the abutment screws 46, 48 so that the plates are prevented from swinging outwardly away from one another beyond the approximate positioning shown in Figure 3v in which they are parallel to one another and perpendicular to the panel.

Each hinge plate carries a pawl linger 53, 54, and it will be appreciated that these travel vertically with' the carrier block and normally lie in the positions shown in full lines in Figure 3, but that each-such pawl nger is movable inwardly to the position shown in dotted lines in that view withy inward swinging of its supporting plate. Y The carrier assembly just described travels in avertically disposedcolumn-likepath behind the panel and onv either side of this path are a plurality of Valve elements, spaced1` vertically from? onev another. One of such valve elements is shown in section in Figure 3, its body being'- generally designated 60. Each-of these valve elements is providedv with an actuating pawl 62 engageable by one of the pawl. ngersas 53. One such valve, termed a pan'ell control valve, is provided for each blower unit-or other controlled device whose action is to be regulated by the system.

The details of. construction ofthe panel con-- trol valves will subsequentlyl be considered inv greater detail, but in connection with the mode of actuation thereof, it isrto be noted that the internal valving. means'Vv is-operable by a plunger 64 which projectsyieldably from` the end of the casing 60 of the valveV toward the path of the carrier-supported finger 53or 54, as the case may be. Pawl 62 hasv a heel portion Y65 engageable with plunger 64 as shown inf Fig. 6.

EachA pawl 62 is loosely carried by a. horizontaly shaft 66 which is perpendicular to' and extends forwardly through the panel' 2'0, where it, carries a rigidlyy attached knob as `68 overlying and adapted to be manipulated from` the front of the panel.` Fast upon the shaft beside the pawl 62v is a sector piece 10 having a` pin l2 projecting from one face thereof into a slot-like opening T4 in the' pawl. As best showninFigure 6, the opening 14 is of relatively large size so@ that the pawl isf of generally inverted U-form.

When theshaft 56 and sector T01-are in the normal operating position in which the parts are shown in Figure 6, the pin .12 holds the pawl 62 in theraised: position shown in Figure 6 in which the'` inner end of the pawl extends iangularly downwardly and inwardly and.` into the path of movement of the pawl finger 53'-, The sector and pin are releasably held in such position by a= springv detent finger 75S, which at such; time frictionally. engages in.v a relativelyv shallow detent notch 'I6v in the` periphery of thel sector lll.v When theY sector is turned. clockwise? (as the partsvare viewed. in FigureG), the pin .1.2i ismoved ang-u'- larly downwardly land the pawl falls under gravity toY the dotted lin'e position shown in that view. The pawl-is sol contoured that at such time it does not projectinwardl'y far enough tolie in the'patlr of vertical movement of the pawl finger, and the pawl iinger may then travel freely'past theiilat face' la of the pawl', which. atsu'clfi time is" approximately Vertical. Withk the pawl: in the rior-` malr operating. posi-tionA shownv inA full lines in Fig-v ure 6, the pawl may be rocked slightly counterclockwise upon its shaft when its lower extremity 80 is engaged by the pawl finger. ,Such upward rocking movement of the pawl is induced by the piston weight and causes the heel 95 of the pawl to push the plunger `54 inwardly.

Positioned adjacent and shown as secured to each of the valve bodies corresponding to the Valve body 69 is a pawl finger releasing mechanism con'iprising a housing `83 which carries a plunger 85 projectable to engage the hinge plate as 45. The plunger is operable by a bellows 86 to the head of which the plunger is |attached. The bellows is sealed at one end to the housing 89. Actuating air pressure is adapted to be delivered to housing 38 by means presently to be described. Each such release mechanism is positioned to coact with its adjacent lvalve assembly as `6l] in such manner that the plunger 185 is engageable, when projected, with the outer face of the hinge plate as 94, when the carrier is in the position in which its pawl finger as 5S is in engagement with the pawl as lB2 for the corresponding valve unit. A spring 90 within the bellows normally retracts the plunger S5. The release cylinders are secured as by screw means SI to individual bracket plates as B3 through which the release plungers 85 pro ject. The panel control valves are secured to the same bracket plates, as by screw means el. The bracket plates are carried by vertical rails 69, 1| mounted on the rear face of the panel on opposite sides of and spaced from slot 24.

It will be understood that panel control valve parts and pawl finger release parts are duplicated for each blower or group of blowers to be controlled from the panel, although parts on opposite sides of the slot 24 are symmetrically opposite in their arrangement. Detailed redescription of the duplicated parts will not be required.

As best shown in Figure 2, the knobs may have pointer-like projections 59, and these are so positioned and the parts are so proportioned that when such pointers are horizontal, the pawl carried by the same shaft as the knob is held in the ready position or lifted position equivalent to that shown in Figure 6, while when the knob is turned 90 in a direction to move the pin 'l2 downwardly away from the pawl and to cause the pointer to assume a vertical position, the pawl drops to the inoperative dotted line position of Eigure 6, in which its valve is not actuatable by the carrier.

The control panel frame assembly also carries a start :and stop valve 95, shown as located near the top of the slot 24 and provided with an upwardly projecting plunger 95 by which it is operable. The details of this valve will also be considered presently, but referring to the manner of mechanical actuation thereof, it will be observed that an actuating arm 98, pivoted upon a pin Ifi carried by a rigidly supported bracket |52 attached to the side of the valve casing 55, overlies the plunger 96 and is movable downwardly to open the valve by depressing the plunger When moved upwardly, the arm frees the plunger and lallows the same to rise and the valve to close. A spring |03 urges the arm 99 downwardly with sufcient force t0 depress plunger 95 and open the valve.

The arm 98 is adapted to be latched in the raised position in which the valve is closed by means of a latching dog in the form of a triangular sheet metal plate ||0 pivoted upon a pin ||2 carried by a guide block assembly |05, iixedly secured to the frame structure behind the panel 20 as by the screws H3. The plate IIU is provided with a latching Shoulder n4 movable te and from a position in which it underlies the arm 98 to hold the arm in the raised, valve-closed position, while when the plate is rocked free of the arm, the spring |03 pulls the arm down and opens the valve. That portion of the arm engageable with the latch is also guided in ya slot |01 in the guide block assembly |06. A tension spring ||5 urges the latch plate to latched position. A rod |05 is pivotally connected to the plate ||0 and extends downwardly beside the slot 24. At its lower end the rod |05 has a laterally bent foot portion |04 which is engageable by the block 26 when the block is pushed down to the lower limit of its travel. The rod |05 is positioned and guided by suitable slide bearing bracket means as i6. The arm 98 has a finger portion |08 at its outer end which also projects into the path of the carrier blocker 26 at the upper limit of travel of the block, so that as the block reaches such upper limit, it engages and lifts the arm 98 to the valve-closed position. It will be appreciated that when the arm is thus raised above the shoulder I4, the latch plate H9 is rocked clockwise as viewed in Figure 10, to latch the arm in the raised position. When the block is pushed all the way down, it engages the foot |04 and, by pulling down on the rod |05, rocks the latch plate in the opposite direction or counterclockwise to move the shoulder ||4 from beneath the arm 98, allowing the arm 98 to be pulled down by spring |03 to open the valve.

A souice of air under pressure is connected to the valve 95. The source may comprise a tank 354 within which the pressure is maintained by suitable compressor means (not shown) and to which connection is made by means presently to be considered in greater detail but which includes a conduit 3|@ leading to the lower end of the valve. The supply pressure delivered by the regulating valve 305 is indicated by a pressure gage |25 supported upon the panel 20 and connected to the supply system at a point below the interrupter valve 3GB by means of a conduit |26.

The air enters the lower end of the body of valve 95 by way of an axially disposed chamber |28 containing a ball valve |30 which is urged toward closed position by a compression spring |32 beneath the valve as well as by the air pressure. The valve body also contains an axial passage |34 connecting chamber |23 to a similarly positioned chamber |40 at the opposite end of the body. Within passage |34 is a pin |35 movable downwardly to open the valve |30 when the plunger 95 is depressed. Plunger 96 is engageable with a second ball valve |35 in the upper chamber |40, the pin |35 between the two valve balls being of such length that only one ball can be seated at a time. The pin |35 is enough smaller than passage |34 so that air may move yfreely through the passage when either ball is unseated. An exhaust passage |38 connects the outside of the casing 95 with the chamber |40, while the central passage |34 is connected by means including a lateral passage |42, coupling |44 and conduits |20, |45 to a pressure reducing valve' |46. The pressure reducing valve |46 is also supported by the panel 20 and may be of any suitable or commercially available variety.

In the preferred embodiment disclosed, the pressure supplied to the start-stop Valve 95 is maintained at approximately pounds per square inch by a pressure regulating valve 305 and a pressure controlled interrupter valve 308, while the pressure reducing valve |46 maintains the pressure in the output conduit |58 from that valve ata pressure of approximately 35 pounds per square inch. The reduced pressure air from the reducing valveV |66, may also be connected as by means of a coupling |52 toa pressure gage |54 mounted upon and visible from the iront of the panel.

The reducedy pressure air from the regulating valve M6V may be led directly to manifolds as |155, |58 connected to the inlets of some or all of the panel control valves, but such direct connection is only employed where it is desired to start the operation of the first of the blowers connected to such manifoldA immediately upon the, opening of the start-stop valve. Such immediate starting is feasible in the case of blowers employing air as the blowingmedium, and in the illustrative arrangement depicted in Figure l, allv of those blowers which are controlled by the valves connected to the manifold |58, at one side of the panel, employ air for blowing. At the other side of the panel, the manifold may be formed in two sections, comprising an upper section |55, the blowers connected to which also employ air for blowing, and a lower section |55A, the blowers connected to which employ steam for blowing. Manifold section |55 is directly connected to the conduit |50. from the reduced pressure air supply source, represented by the reducing valve |45. To prevent delivery of steam to the steam blowers connected to manifold section |55A until the re- Inoval of condensate from the steam supply system,. a timed delaying device is interposed between manifold section i55A and the valve IQB to prevent delivery of air to manifold section |55A for a time adequate for the draining of condensate from the steam lines. The time delaying means will presently be considered in greater detail, but it includes a valve SI5 connected to an output conduit 325 from regulating valve |46 and in turn connected to manifold section |55A by a conduit S2?.

As previously indicated, the panel control valve assemblies are supported in vertically spaced relation by and upon the back of the panel E@ in such manner as to be successively actuatable by the pawl linger 53 or the pawl finger 5d of the carrier 25. One such valve is shown cross-sectional'ly in Figure S and the body thereof is generally designated It will be understood that all such valves and their appurtenances may be of like construction and that description or' one will suillce.

The construction of the valve 5E? will be seen to be generally similar to that oi the start and stop valve Q5, previously described. The low pressure air enters the axially disposed chamber |62 at the rear or manifold end of the valve through the coupling its. Chamber |62 contains a ball valve 55 and a spring i' which urges the valve balll against the seat formed by the outer end of the reduced central passage |68. When the ball |66 is off its seat, communication is established between the low pressure source and a conduit lr connected by the coupling |`2 to a lateral passage communicating with central passage ist. Passage its communicates at its opposite end. with a chanil er ii which is also larger than the central passage so that a sect is formed at the juncture of passage |58 and chamber li for a ball Valve arranged in the latter chamber. A stem ils winch i, longer than passage but ci substantially lesser diameter than such passage, prevents the seating of more than one of the ball valves H35, llt at a time,v unseatlli ing the opposite ball whenever either of the balls moves into engagement with its seat. An exhaust port |86 in the valve body til connects chamber |5 to atmosphere. Chamber |75 extends as a straight bore of uniformA diameter to the inner end of the valve body and slidably supports the actuating plunger 54 previously referred to. Plunger 6:3 is engageable with the valve ball |16 and when pushed' inwardly forces the ball |16 against its seat and the ball |56 olf its seat. The plunger is engageable by the pawl 62 as previously described. It will be seen that ywhe-n the pawl is lifted by the pawl finger 52, the, plunger |513 is forced inwardly to close valve H6 and open valve |56, establishing communication between the low pressure source and the conduit |15, while when the pawl is released by the pawl iinger, valve |55 closes under the inuence of air pressure supplemented by the spring |55, valve H6 being opened to` vent the conduit Il to atmosphere by way or" passages li, 68 and |80.

In the case of each of the valves corresponding to the valve just described, a continuation of the conduit corresponding to the conduit HB connected to the valve outlet extends to the remotely located controlled apparatus or blower unit which is controlled by the valve in question and is termed the control line or control conduit. Each of the conduits W5 is connected to a fitting and coupling member 85 carried by the bellows casing t8, and the control conduit as |36 is connected to coupling member it. As previously explained, the reduced pressure air delivered to the bellows casing 8S from the low pressure source is incapable of collapsing the diaphragm 86 to release the pawl linger 53 from engagement with the pawl 62, but upon a sufcient increase or" pressure in the control line, the bellows is collapsed, overcoming the resistance of the distending spring 9! to project the release pin 85 into engagement with the hinged arm 45 which carries the pawl finger.

Each control conduit as |86 extends to the diaphragm housing its of a diaphragm-operated valve as E9e (Figs. l and 3) which controls the delivery of power air to the blower actuating inotor. In the case of control line |36, it is assumed that the blower to be controlled is one which rotates in one direction only and is not reciprocable. It is also assumed that the air motor |92 which drives the blower also drives at half speed a timing gear 245i connected to the motor through the agency of a suitable mechanical connection not necessary to be considered in detail but which includes a motor-driven pinion 25| meshing with the timing gear. The operating mechanism of the valve i563 is such that the valve is adapted to be opened by the application of the reduced pressure (e. g. 35 pounds per square inch) control air to the diaphragm chamber |38. Valve |90 controls communication between the source of air under pressure of approximately 80 pounds per square inch, and an air motor l5? which drives the controlled soot blower. The power air for the motor is delivered to the valve 55 through a conduit |543, and a conduit |55 extends from the valve |96 to a motor control valve- Shown in Figure 13. The casing of the motor control valve is generally designated |95.

The motor kcrnitrol valve casing ist may be mounted directly upon or adjacent the air motor mit, and the motor in turn is s o connected to the valveY to actuatc the same to a position to interrupt the supply ot power air to the noter aiter the motor has turned through a desired angular interval. The power air line |95 is connected to a side port |98 formed in the valve casing |96 and which communicates with a cylindrical chamber 200 in the valve casing. The chamber contains a slidable poppet valve 202 normally held in a raised position by a compression spring 294 beneath the valve so that the power air passes under the valve and out a port 205 on the other side of the valve, whence it is conducted by way of a conduit 208 to the motor |92.. Valve 202 is carried by a stem 2|0 which projects from the valve casing to serve as a device for manipulating the valve. When the valve is in the raised position, it interrupts communication between the power air line |95 and a valve port 2|2 which extends through the side of the valve casing above the valve chamber 200, while when the valve is pulled down, communication is established between the ports |98, 2|2V through an upward and coaxial continuation 2 |4 of the chamber 200. The chamber 200 is substantially larger than the valve, as shown, to allow free air low around the valve, while the upper continuation section 2|4 of the chamber is smaller than the valve, as also is the lower continuation portion 2 |5 which houses the spring 204 and which provides communication between the valve chamber 200 and the port 205. Shoulders 2 I5, 2|8 are thereby provided between the main valve chamber portion 200 and the extension portions 2|4, 2|5, respectively, the valve 202 when raised seating against the shoulder 2|5, and when lowered seating against the shoulder 2|8.

The port 2|2 is connected by a conduit 220 to an orifice member 222, which is in turn connected to the control conduit portion |86.

As previously indicated, the power air for driving the motor is at a higher pressure than the control air delivered to the diaphragm chamber 88 by way of the control conduit |86. When the valve 202 is pulled down, therefore, the higher pressure air from the air power line |95 is delivered to the conduit 220 by way of valve passages 2 I4, 2 I2, and the pressure is thereby raised in the control line |86.

When the pressure in the control line reaches a predetermined value, which may be of the order of 55 pounds per square inch, due to downward movement of valve 202, the corresponding pressure within the bellows casing 88 connected to the line |85 (which is the upper left-hand unit as the parts are viewed in Figure 4), overcomes the spring 90 and collapses the bellows diaphragm 86 suioiently to cause the plunger 85 to push the pawl finger supporting arm 45 inwardly, moving the pawl finger 53 from beneath the pawl E2, thereby allowing the pawl to drop and the ball valves |66, |15 to move to the right, closing the valve |56, and interrupting communication between the low pressure air source and the control line and venting the control line to atmosphere through valve chamber |75 and exhaust passage |80. By reason of the inclusion of the orifice member 222, the pressure in the control line |86 is vented through the exhaust passage |80 more rapidly than the pressure can be maintained through the orice in the member 222, and when the control line pressure and the corresponding pressure in the diaphragm chamber |88 fall away suiliciently, the diaphragm-operated valve |90 closes, interrupting the high pressure air supply. As the pressure continues to fall away in the control line and in the connected conduit 220 and the upper valve chamber 2|4, valve 202 is again lifted to re-engage the upper seat 2|6, reconnect- 10 ing the air motor to the high pressure supply line 55, so that the unit is ready to restart when the pawl 52 is again actuated.

It will be understood that when the pawl nger 55 is freed from the pawl, the carrier 26 and parts carried thereby are released and rise under the inuence of the counterweight 30. If there were any other panel control valves positioned above the one connected to line |85, one of the pawl lingers 55 or 54 would engage the pawl of the next higher valve having its pawl in the operative position, and such next pawl in the sequence would then be raised to initiate operation of the blower head controlled thereby in like fashion. In the shown arrangement, however, line |86 is connected to the highest panel control valve, so that when the carrier is released by its tripping pinthe carrier rises to engage and lift the ringer |58, allowing the valve 95 to close to shut down the system. The blower control mean-s shown in Figure 13 also incorporates mechanism for actuating the valve 202 when the blower head is in predetermined angular positions. A timing gear 240 is driven in timed relationship to the blower nozzle and may be geared or otherwise positively related to the blower nozzle by any suitable means not necessary to be disclosed in detail herein, since such mechanical features do not form a part of my present invention. The timing gear 240 carries a trip pin or lug 242 engageable once during each revolution with a valve actuating arm 244- when such arm is in an operative position, although as will be seen such arm is movableinto and out of the operative position. Arm 244 ispivoted as at 245 to a support 246 which carries the valve, timing gear, and associated mechanism. The arm 244 is also rockable in a plane perpendicular to the plane of the gear 240 and perpendicular to the stem 2|0 through a limited arc sufficient to move the arm into and out of that part of the path of the lug 242 farther from pivot 245. The stern 2|0 extends through an arcuate transverse slot 250 in the arm 244, which slot is long enough topermit such lateral movement of the arm. The arm is movable transversely of the gear into and out of the path of lug 242 by a piston 252 movable in the cylinder 254 in a path parallel to the axis of the gear-240. In Figure 13, the cylinder and piston 254, 252 are turned 90 about an axis parallel to the arm 244 so that they may be shown in the plane of the paper, although they are actually perpendicular to4 such plane, as shown in Figure 14, so that when the cylinder is energized the arm may be moved inwardly into the path of the lug, and vice versa. The arm 244 is centrally offset as indicated at 243 so that only the part thereof shown at the right in Figure 13 is engageable by the lug. The arm 244 projects into a lateral slot 255 in the piston 252 and through a clearance opening 256 in the cylinder. The slot 255 forces the arm 244 to move with the piston in an axial direction to carry the arm into and out of the path of travel of the lug 242, but permits the arm to swing about the axis of pin 245 to the extent necessary to actuate the valve 202. The arm actuates the valve in a downward direction only, as the parts are shown in the drawing, acting upon the stem 2|0 through an adjustable abutment carried by the lower end of the stem and comprising a pair of jam nuts 258 and a compression spring 265 on the stem between the arm and the jamb nuts.

The piston 252 and arm 244 are urged outwardly away from the gear 249 by a spring 26| within the cylinder 254 and bearing outwardly against the bottom of the piston. Spring 26| yieldably maintains the arm 244 out of the path of movement ci' lug 242 except when fluid under pressure is delivered to the space within cylinder 254 above the piston 252 through a conduit 264, which connects the head of the cylinder to the port 265 formed in thevalve casing |96 and communicating with the valve chamber 20|). By virtue of this arrangement, the arm 244 is maintained in the path of the lug 242 at all times while the valve |953 is open. If the timing gear 249 is driven at half the speed of the blower nozzle, it will be appreciated that since the lug 242 commences to rotate clockwise, as the parts are shown in the drawing, from an initial position under and close to the arm 244, each time the blower unit is started in response to initial delivery, of motor power air to the valve |96 and airV motor |92 through conduit |95, the blower nozzle will make two full revolutions to carry the pin 242 through approximately one full revolution before the lug 242 re-engages the arm 244. When. the air motor is in operation, the arm 244 is held in the path oi movement of the lug 242 by the piston 25,2 in the manner described. As the motor completes the driving of the nozzle through its intended arc of rotation, the lug strikes the top of the arm, as the parts are shown, thereby moving the valve 232 down from the position shown in full lines to the position inY which` it seats against the shoulder 2I8 toV deliver the higher pressure air to the control line and trip the releasing means at the panel board to shut off'` the diaphragm-controlled valve |96 inthe manner previously described.

' .In so actuating the valve 292, the arm 2,44 compresses the spring 26e somewhat, since the.A motor cannot be instantly stopped and spring 26Il permits some overtravel. When the pressure is relieved in the cylinder 254, therefore, and spring 251,. lifts the arm 244 clear of the lug 24?.,15116 pressure previously exerted upon the spring 2640 by the arm 244 is relieved, and arm 244 springs back in response to the expansion of the spring 269 far enough to overlie the lug 242. VWhen the unit is again started. therefore, the arm, 244 is not in a position to block the lug 242 and the lug moves out from under the arm 24A and continues for a, full revolution, as previously stated, before re-engaging the arm 244. Before the lug has completed its orbit, however, the piston 25.2 has again pushed the erm downwardly into the path ofthe lug. It will be understood that if it is desired to permit the blower to turn through a. shorterarc, additionalv lugs may be secured to the timing gear as indicated in dotted lines at 242a.

Figure l shows the applicability of the principles of this invention to the control of a plurality of Iblowers of different types, some of the blowers employing steam as the cleaning medium and some utilizing air as the cleaning medium, while the air blowers may operate at different pressures. All of the blowers are air controlled and air driven. l

The motor driving and control air is supplied to the system from a suitable source which may comprise a tank 354 within which pressure iS maintained by one or more compressors and suitable control apparatus which of course vary widely without departing from the present. invention, but a suitable arrangement of which will presently be indicated. The air delivery pipe from such source is designated 339 and the air passes iirst through a hand valve 362, a filter 304 and a pressure regulating valve 305, which may be set to maintain an output pressure in the neighborhood of pounds per square inch. From the pressure regulated output of the valve 365, the air is taken through a conduit 396 to a pressure controlled valve 398 and thence to the conduit 3 I 9 which leads to the start-stop valve 95 mounted upon the panel 20, as previously described.

The pressure controlled valve 399 is operable by a diaphragm unit 3I2 connected by means including a conduit as 3 I 4 to the tank 356 or other source of pressure air supply. Valve 398 is arranged to interruptr communication between conduits 395, Siti whenever the pressure in the supply tank drops below a predetermined value and to re-open when the desired value is again reached. This prevents the starting of any blowing unit whenever the pressure at the source is too low, and allows my improved blower control system to be used with receiver tanks of limited capacity, interposing delay whenever necessary in the operation of the blower system to allow the pressure to build up in the air supply system;v

The reduced pressure control air from regulating valve |46 is conducted to the right-hand manifold |58 and to the upper left-hand manifold section |55 through conduits |59, |56', as noted previously, but the lower left-hand Vmanifold section I55A is connected to the pressure regulating valve |46 through time delay means including a pressure controlled valve SI5, the action of which is regulated by a timing mechanism consisting of a calibrated receiver SI5 connected to the diaphragm-type operating unit 3I8 for the valve 3I5 by a conduit 329, conduit 329 being connected to the output of the start-stop valve through a supplemental start-stop valve 504 by way of a restriction orifice member 322 and conduits 502, 324, the latter connected to the output conduit |45 from the main start-stop valve 95. The function of the supplemental start-stop valve 594 will presently be considered, but assuming that both of the valves 95, 594 are open, the rate of pressure build-up in the system comprising the tank 3I6 and actuating diaphragm chamber 3|8 is determined by the orice in the member 322, While the time required to build up to the actuating pressure is determined by the capacity of the tank 3I6. When the actuating pressure is reached, the normally open valve 3I5 closes to establish communication between the reduced pressure control air supply source and the manifold section I55A.

The time delay mechanism just described is employed because the blowers whose actionv is governed by panel control valve means connected tomanifold section |55A utilize steam for blowing, and the delay thus interposed insures a suicient interval for the escape of condensate through the impulse trap 429. A steam blower 334 is shown connected to the lowermost panel control valve, designated 338, connected to manifold section I55A. Steam is supplied to blower 334 through a diaphragm-operated valve 328. The actuating diaphragm chamber 326 of the valve 328 is also connected indirectly to the output from the start-stop valve S5 through the supplemental start-stop valve 595. The valve 32S receives blowing steam from a suitable source, not shown, through pipe i2-il and, when open, delivers the steam through a pipe 332 to the blower unit generally designated 33d. The details of construction of the blower need not be considered since they form no part oi my present invention,

although a suitable blower is disclosed in the copending application of Le Roy S. De Mart, Serial No. 766,183, filed August 5, 1947. The continuation 335 of the pipe 332 may lead to the blowing steam inlets of other steam blowing units, the action of which may be controlled by other control valves connected to the lower manifold section |55A.

The action of the blower 334 is controlled through the control. line 336 which may correspond to the control line |86 previously described in its general connection and arrangement and which is connected in like fashion to the output of a control valve 338 comprising one of the three-way control valves carried by the control panel corresponding to the valve 68 previously described.

When the valve 338 is opened in the course of operation of the valve-actuating carrier assembly 25 of the control panel, control pressure air is not introduced to the line 338 until the time delay mechanism has completed its operation and opened valve 325, but when valve 3|5 opens, air passes through line 321, manifold section |55A, valve 338 and conduit to the diaphragmoperated valve 349 corresponding to the valve |98 previously described. Valve 346 is thereby opened by the introduction of such pressure to the actuating diaphragm chamber 342, and the blower actuating motor 344 is operated to open the steam valve' in the blower head and to rotate and/or reciprocate the blower unit as the case may be and in accordance with the details of construction of such blower. The control valve for the blower motor is designated 345 and it will be appreciated that if the blower unit is of the type which is rotatable but not reciprocable, valve 345 may correspond in. construction to the valve |95 previously described, while if the blower unit is of the reciprocating-reversing type, the valve may correspond to the disclosure of vthe copending application of Le Roy S. De Mart, `Serial No. 60.435, led November 17, 1948. In4 either event, the control. connections are the same, but with the motor 344 of the reversing-type, two connections are required from the motor control valve 345 to the motor 344, as shown, since one motor port cannot be directly discharged to atmosphere as in the case of the irreversible motor |92. The

orifice member 346 in the return conduit 348 from the motor control valve 345 corresponds to the orifice member 222 previously described.

Blowers employing air as the blowing medium are diagrammatically indicated in Figure 1 at 35|] and 368. Blowing air is supplied to the blower 358 through a conduit 352 connected to a high pressure tank 354. The tank 354 is adapted during operation oi the system to be maintained at one pressure :for a predetermined interval during which certain of the air-operated blowers are functioning, and at a different pressure while other blowers are operating. For example, the blower 356 may be designed to operate with air supplied at 350 pounds per square inch, and while this and similar blowers are operating, the pressure in the tank 354 is maintained at 350 pounds per square inch, while other blowers as 360 also utilizing air as the blowing medium may be arranged to operate at a lower pressure, for example, 250 pounds per square inch. The automatic regulating means which controls the pressure in the tank 354 is so arranged as to maintain the pressure in tank 354 at 250 pounds per square inch during the operation of blowers such as the blower 368. The pressure air supply for prises a pair of pressure control devices 363, 310

supplied with air at constant pressure through a pressure regulating valve 312 connected by a conduit 314 to the tank 354. Conventional filtering and gage means designated 315, 316, respectively, may be incorporated in the inlet line 314 to the pressure control unit. The control device 368 may be adjusted to deliver an output pressure of 250 pounds per square inch, and the control dey vice 318 may, for example, deliver an output pressure of 350 pounds per square inch. A diaphragm-operated three-way diverting valve 318 has one inlet connected to a conduit 380 from the pressure regulator 368 and another inlet connected to a conduit 382 from the pressure regulator 310. The outlet of the Valve 318 is connected by a conduit 384 to the actuating diaphragm chamber portion 385 of the valve 3,58y while the valve 318 has an actuating diaphragm portion 386 by which the Valve is operable to a1- ternatively connect the conduit 384 to either the conduit 388 or the conduit 382, the arrangement being such that when actuating pressure is delivered to the diaphragm chamber 386 through the conduit 388, the valve 318 provides connection between conduits 382, 384 only, while when the pressure is relieved in the chamber 386, the valve 318 connects the line 384 only to the line 386.

Air under pressure is supplied to the main storage tank 356 from suitable compressor means, not shown, through a conduit 399, and the tank 356 is connected by a conduit 392 through a hand valve 394 and regulating valve 358 to the dual pressure supply tank 354.

It will be understood that one or more additional valves shown at the left side of the panel diagrammatically illustrated in Figure 1 may also be arranged to control steam blowers, and these are also connected to manifold section |A, as for example valve 424, but the control valves 482. 404, 405 and shown at the right in Figure 1 are all for air blowing units, as also are the valves connected to manifold section |55. These'panel valves are alsoV connected to their respective blowers by individual control lines as 335, 396, 398 and 406. Each of these panel valves is connected to its manifold through a check valve at 498 which prevents back ow through the panel valve to the manifold.

Valves 404 and 69 are arranged to control the action of blowers utilizing blowing air at 350 pounds per square inch, while valves 402, 405 are to control the action of blowers utilizing air at 250 pounds per square inch. The control lines 395, 398 are connected directly to the diaphragm chambers for their respective motor air control valves as 4|9. This will be seen to correspond to the arrangement of the control line |88 previously described connected to diaphragm chamber |88. It will be recognized that valve 4| [l and the motor control valve 4 2 may correspond either to the parts shown in Figure 13 or to the parts 340, 345 employed to control the steam blower 334, an equivalent oriced control member 4|4 'and runs through its operating cycle. "after the carrier again resumes its upward move- 1-5 also ,being connected between the motor control valve 4l2 and the control line 398.

iEach ofthe control lines 393, 400 from the con trol valves 404, 60 Afor the higher pressure air blowers is connected through a check valve as 415, 4I3 to the conduit 388 leading to the actuating diaphragm chamber 386 kof the valve 318. All of the air blowers are supplied with blowing air from the tank 354 through a common pipe 352 suitably branched, as shown, for connection thereto, but when the lower pressure blowers as 350 are in operation, since there is no control air connection to the diaphragm chamber 383, the valve 318 connects the 250 pound controller 358 to the diaphragm chamber 385 of regulating valve `358 ,so that the air is 'delivered to the tank 354 at a rate such as to maintain the pressure therein at 250 pounds per square inch. When one of the 350 pound blowers as 350 is in operation, the control air in its controlling line as 400 is also delivered to the actuating diaphragm chamber 388 of the valve 318 and the latter valve then connects the 350 pound controller 310 to the regulating valve 358, which opens sufliciently to deliver added pressure to the tank 354 and raises the pressure therein, and inthe lines leading to the blowers, to 35.0 pounds per square inch for operation of the high pressure blowers. The check valves M5 and M5 prevent back flow from one control line to another and so prevent unwanted air suppl-y toa controlling line of a unit which is not supposed to be in operation.

The check valves 408 prevent such an unwanted reverse connection from one control valve to-another in event the pressure controlled valve 308 closes to allow the pressure to build-up in the system Vas previously explained.

When the system is to be started, the carrier is pushed down to the bottom of the slot 24 to open the start-stop valve 85 as previously explained, and also .to open supplemental start-stop valve 504. The carrier is then released so that it can rise under the influence of the weighted piston 30. Assuming that the pawls for all of the control valves are set in their operative positions, the carrier rst opens the control valve 402 which is shown as arranged to control the operation of a low pressure air blower, which starts without delay. As soon as the valves 95, 504 are opened,

pressure commences to build up in the timing re- 'steam-operated blowers, although the valves in the blower units themselves remain closed. During the time required for the timing receiver to build-up pressure sufficient to open the pressure controlled valve 3l5, condensate forming in the steam lines 332, 335 may be drained by suitable means such Vas a conventional impulse trap device indicated at 420. After blowing of the unit (not shown) connected to the control line 395 is completed, the carrier rises to engage the pawl of valve 338 to open that valve so that air can flow into the control line 336 leading to the steam blower unit 334. If the timing interval determined bythe receiver 3l6 is not completed, the opening of valve 338 has no effect since valve 3I5 `remains closed and no air can enter the control Vline 336. The carrier accordingly remains in the indicated position, while the timing function is completed and also while the blower 354 starts Therement, next actuating the valve 404 which controlsone of the high pressure air blower units in the manner previously described. It will be recognized that the blower whose operation follows the air blower connected to the valve 404 is the blower (not shown) connected to valve 424 and that the control line 425 connected to valve 424 is supplied with control air without delay. since the timing system controlled by the receiver 3i3 only functions when the system is rst put in operation.

It will be appreciated by those skilled in the art that where retracting-type blowers are used, it would be undesirable to allow a blower of this type to remain in the projected position in event valve 308 should close before completion of the full cycle of operation of such a blower. To overcome the danger of damage to a retractable blower which such a situation would entail, I provide means adapted to form a holding connection. maintaining the air supply to the contr-ol panel in event valve 308 closes, until any blower which happens to be in operation at the time of such closing has completed its full cycle of operation. It will be understood that this insures the retraction of all blowers to safe positions. The holding connection includes a holding valve, the body of which is generally designated 450, connected to a continuation 30! of the air supply line 300, beyond the point at which the branch conduit 306 to the valve 308 is connected, but in a position such that all of the power motor air must flow through the holding valve. A conduit 452 connected to the holding valve leads to the conduit 3I0 so that valve 450 and conduit 452 may form a shunted connection around the valve 308.

The details of construction of the holding valve are shown in Figure 15. As there indicated, the power motor air enters the right side of the valve through the conduit 30| and acts upwardly upon a weighted piston 454. Vlhen air in substantial volume is flowing throughthe .system to one of the air motor supply conduits as 455 or 45E, thepiston 454 is lifted, raising a valve-like boss portion 458 formed upon the bottom of the piston free or" its guiding opening 435 in the casing, and the air flows out to the air motor supply conduit 455 through a port 430 formed in the opposite side of the valve. Also carried by and projecting ldownwardly from the weighted piston 454 is a needle valve 432 which is held off its seat by the lifting of the piston when air is flowing through the motor supply line, as indicated, but which drops into engagement with its seat portion 434 at the bottom of the valve housing when the substantial flow reqired by blower driving motor is interrupted. The port 464 controlled by the needle valve is connected to the conduit 452. It will be appreciated that, this valve being gravity operated, it should be installed in the vertical position, and it will also be understood that the port 404 is of sufficient size to provide a suicient supply of air to the control panel when the needle valve is open. It will be observed that the boss portion 450 is of cylindrical form and of lesser diameter than the piston portion 454. Portion 453 has an easy sliding ft in the enacting cylindrical portion 4555 forme-' in the valve casing, but these parts do not forni a tight seal, so that a relatively gradual pressure equalization can place permit the piston to fall after all of the diaphragm valves in the motor air lines have closed. The cross-sectional area of the portion 453 is sulicient so that when a diaphragm valve as i353, 4m or 340 in a motor air line opens, :the differential pressure beneath 17 port 458 is suicient to lift the piston, while when the piston is raised a lesser pressure will hold it up due to the larger piston area directly subject to the pressure of the air supply.

Where the system includes a considerable number of blowers, most of which employ air for blowing and only a few utilize steam, it is desirable to provide supplemental automatic valving means to control the illow of blowing steam in such manner that the steam is delivered to the blower steam piping only when needed, and is cut off after completion of the operation of the steam units, even though the air units continue operation.

vIn the arrangement shown diagrammatically in Figure 1, it is assumed that only the blowers connected to the control valves 338 and 424-v utilize steam for blowing, and that the other blowers discharge air. The diaphragm chamber 326 of the valve 328 is not connected directly to the start-stop valve 95, but is connected by' a conduit 502 to the outlet of the supplemental steam unit start-stop. valve 504, which is in turn connected by the conduit 324 to the main startstop valve 95. The construction of the valve 504 may correspond to that of the valve 05, but as best shown in Figures 4, 5 and 16, it is mounted near the lower extremity of the travel of the carrier 26 and so arranged that valve 504 may be opened by the carrier as the carrier reaches the bottom of the slot 24. The valve 504 may be carried by the bracket 34 which supports the dashpot cylinder 32. When the plunger 506 is raised, the valve 504 interrupts communication between conduits 502, 324 and vents the conduit 502, allowing the diaphragm valve 328 and the timing valve 3|5 to close. Whenthe plunger 50E is depressed, it closes the vent (not shown) of valve 504 and connects the diaphragm chamber 326 to the air supply to open the steam valvey 328, as previously described. The plunger 506, as in the case of the plunger 9,6 oi the valve 95, is normally raised by an internal valve spring, but the valve is adapted to be opened by an arm 508 pivoted upon the bracket 5|0 fastened to the side of the body of valve 504 and overlying the plunger 506. At the lower limit of the travel of the carrier, a block 5I2 attached to the carrier is engageable with the end of the arm 508 to movethe same downwardly and open the valve 504, and when the arm 508 is moved all the way down to the valve-open position, a latch piece 5I4 pivoted at 5I5 upon a fixed supporting bracket 5| 6 attached to the bracket 34, swings to an overlying position with respect to arm 508 to hold the same down and keep the valve 504 open. The latch piece 5| 4 is in the form of a bellcrank having a generally horizontal actuating arm SIB projecting forwardly toward the panel 20. A wire link 520 is secured to the arm 5I8 directly behind the panel and extends upwardly to a latch release arm 5.22 pivotally supported by the panel frame assembly and engageable by a trip dog 524 carried by the carrier during upward travel of the latter. In the illustrative arrangement depicted wherein only the valves 338 and 424 are connected to steam units, the release arm 522 may be positioned just above control valve 424 so that after the carrier is released by the release bellows plunger of valve 424 and rises therefrom to allow valve 424 to close, the dog 524 on the carrier strikes the release arm 522 to urge the same upwardly together with the link 520 and arm 5|8, thereby releasing the latch piece 5|4 from engagement with plunger steam to the steam units.

actuating arm 500 and allowing the valve 504 to close. A compression spring 5H trapped upon plunger 506 beneath arm 508 urges the arm 508 upwardly and so augments the effect of the valve spring (not shown). As the carrier continues upwardly to sequentially control the operation of the remaining air blower units after leaving the valve 424, the steam is cut ofi in the steam blower lines by the resultant closing of steam valve 628. This avoids the wasting of steam as will be understood.

The means on the carrier for actuating the arm 522 comprises a release dog 524 of generally triangular shape extending angularly upwardly and laterally from the carrier, to which it is pivoted upon a pin 525 in such position that its upwardly and outwardly extending nose portion 526 is adapted to underengage the release arm 522 as the carrier reaches the level of arm 522, and to swing such arm upwardly to release the valve and allow the same to close as previously described. The arm 522 is swingable upwardly far enough to allow the nose portion 526 of the dog 524 to travel past it as the carrier continues its upward movement, while when the carrier is moved downward- 1y, the dog 524 acts like a latch piece, being cammed inwardly by the end of the arm 522 and swinging out of the way of such arm as the carrier is moved downwardly past the end of the arm.

It will be understood that if the steam units were connected to panel control valves located near the top of the panel rather than near the bottom as shown, the supplemental start-fstop valve might be biased to open position rather than to closed position, but adapted to be closed and latched in the closed position by full depression ofv the carrier, so that the supplemental start-stop valve would remain closed until released by the trip dog, and then allowed to open to introduce In any event, it will be seen that the supplemental valve 504 insures that the steam lines are supplied only during the steam blowing portion of the cycle.

While it will be apparent that the preferred embodiment oi the invention herein disclosed is well a traveling actuator, biasing means urging said actuator in one direction, the actuator being manually movable in the opposite direction, re-

leasable latch-type blocking means carried partly by the support and partly by the actuator and including a plurality of blocking elements positioned in spaced relation along the path of travel of the actuator and movable into and out of positions in which they block movement of the actuator in the direction induced by said biasing means, a portion carried by said blocking element and limitedly movable by said actuator when engaged thereby, under the inuence of said biasing means, a diverting device movable by and in response to such limited movement, and an independent latch releasing device appurtenant to each of said blocking elements for releasing the same from blocking engagement with respect to the actuator.

2. Means as set forth in claim 1 wherein each of said blocking elements comprises a limitedly shiftable actuating element and one of said diverting devices is provided for each blocking element; each divertingdevice comprisingra uidzdie-l verting valve, individual vshifting vmeans .fori-- manuallyimovingvea'ch of said actuating elements' intoi'andlout ofblockinglposition, `each 4of saidv shiftingmeansbeingprovidedwith an observable* 1 part topermit observation of' the positionor saldi;

shiftin'gnmeans and thereby va "determination ofi the .setting ofthe .appurtenant blocking member. c

3.1Means asset forth in 'claim l wherein'fsaidia actuator includesa latch piecezmovable laterally: with respect to the path of movement of the actu. atorlbiril' held: against" unwanted x longitudinal movementwitl'r respect-.toithe actuator; said latchf'.

piece beingf'successively: engageable withsaid: bloekinggelements when the latter are in blockingI position; anddisengageable lfrom; the blockingele-u Y ments lto ireezthe actuatorforcontinueditravel in responsel to "such :lateral movement ofiV the, latch piecei? 4..1 Means asset forth. in yclaim l2 whereinusaid actuator'includes a latch piece-movablelaterally;

with respect to' the *.patlr of. movement of the vactu-e.: y atorbut' held f against unwanted longitudinal:. movementzwith'respect to. the actuator, ssaidllatchz:

piece; beings successively: fengageable' with :said:

blockingelementswhen theilatter are in 'blocking'x position, t and'v disengageablei i rom tthe blocking;v elements tofreelthe actuatorfiorcontinued. trav'elvl in response-itc; suchilateral rnovementofzthe .latch pieces:

5. .Meanszassetforth in .claim 2 zwhereinssaidA 11 actuator. includesra latch Vpiece movable laterally;

with respect tothe path of movementrof the actua.:

ator but." held l'. against` unwantedV longitudinali:

movement-With respect to"V the. actuatonrsaid latch piecexbeingz; successively? engageable'v .fwith .bsaid 4 blockingl elements Lwhen the: latter are `in blocking Y position, and-disengageable; from the'blo'cking clef-.i

ments tolfree the; actuator' for. continued travel in response Lto "such "lateral movementoi the'. latclrnc piece, means .for connecting. a isourcefof' control;`l fluid-undenpressure toeach off said valves, means': for connecting a control;conduitfrornieacn valve to Y"a :controlled soot blowerffunit 'stationrorftlie such -conduit tothe source or alternatively; tolvent the conduitf 6.?Means asv seti forth 'in claimA y2 ,wherein lsaid-,- actu'atorincludesV a klatch piece movable. laterally with respect to the path .ot'movementi of zitlrefactuator but held against unwantedlongitudina'l movement; Swith respectzito' Pthe actuator, said latch'fpiece beingy successively "engageablezfwithrf saidrlblocking -felementsiiwhenwhe latterizarexin i blocking `fposition, land :disengageable Yfrornthen.:

blocking; ,-elementsgto freeV the: 'actuatori :fon :cons-1 A tinuedzdzravel'finresponse toxsuch'lateral moi/eevr ment v'ofpthe'` latch piece,imeans for connecting 4'a source-tofv contro'l.: fluid runder `pressure to eachp offsaidevalves,fmeans for `connecting a controlr",

conduitffrom each `valve'toY a;controlledzsootzf` blower-aunitf station 'orl the like, s each such "valve," beingnorma'lly maintained in na position tosvent' the conduit 'but shiftable'by the actuator; to f' connect: such conduitito .the source` movement=-witlr respect" to-'the actuaton. said,

latch piece: being` successively irengageablei with? said `blockinglements` when the -la-tter- -are in blocking; position; and. -disengageable- :front the blocking-:elements to. s freethe actuator ifor cone;

menti'r off the" latch piece,Y .1 means fior; connecting a source of controlv iluid.under'pressuretoeachiw of. saidv valves, means forconnecting a control" conduit from each 'valve toV a controlled sooti #blower unit stationor`r the like, veach such valve being lnormally maintained Y in Ya positionV to vent;

thev conduit but shiftable by4 the actuator toA z connect; such conduit'to the source, meansV for:

connecting; a source'of power iiuid under a dif-f ceren-tipressure to an operative device atleach* controlled unit station, including a control valve i: atA eaclr Station to which. said controlconduit is connected and to which saidlfsourcexof f powei'.- uid and the operative device.gare=also1fadaptedY'` f tobei'connected, said control valve vbeing;movable to' selectively connectthe power nuid source vtoi the device to drive thesame or..to the control-f conduit to; change. the pressurexin thenlatter,4

said, latch releasing. .device includingran` .nperat-i :'i-ing. elementconnected to thei control conduit vand movable4 response to` a changent-pressure in' said y'control conduit;

8.. Means as set forthxineclaimfl wherein'each divertingdevice comprises a iiuid :diverting valve,

`Ineansior; connectinga source Aof controlxiiuid` underzpressurefto eachof said valves-'means for Y- connecting Aa controlconduit from each valve to -V a `controlled' soot blower unitstation or thelike;

each such valve being shiftable to connect suchf-:f conduitto the source or alternatively to .venttheconduit.

9.Means as setforthiin claim 1 wherein each^f diverting devicecomprises a uid divertingjvalve;

meansgioriconnecting .a source of control fluidi actuatorto connect' such conduitrtothe sourcef- 10. Means as set forth' in claim 11 wherein each-- diverting; device-comprises' a nuid diverting valv"e,-V means (for connecting a source of control` u'id? underv pressure to each of said valvesjmeansior ifconnectinga control conduit ffrom each valve v tozzafcontrolled soot blowerun'it 'station or the like, each such valve being normally maintained# inra 'position to vent the conduitbut shiftable by Y the'V actuator to connect such conduit tofthe ysource, means for connecting-a sourcefof powers' I'luid 'under a different pressure-'toV an operative device'A at; each controlled unit station; including j a controifvalve at each station to whichrsaid con-1 trolivconduit `is Yconnected'A and V'tow whichA vsaid ,sourcezofA power-,fluid and the-operative devicekv arelalsoadapted 'to' be connected, said control valvefbeing movable to selectively Vconnect vthe power-"fluid Vsource lto' thel device --to drive-the Y same or tov the control conduit'to change the :pressure inthe latter, said latch releasing device including an operating element connected-to the I control conduit 'and movablein `response to afr change of pressure in said control conduit;A

11'; A 'sequence controlling andactivating and deactivatinglsystern vfor a Vplurality-of motor-v driven soot blowers, said system including a con: trolv station and a pluraltyof controlled sta--Y tions, the control 'stationlbeingfconneotable.to

a -sourceofy control uidfunder pressure, -eachfA controlled lstation including'a driving motor for-f a soot'blower, a control conduit:'connecting` they control: station tof'each :controlled *stationyand adapted'to convey control 'uid' pressure'toftheef controlled station, a cross-connecting -valverattinued `vV`travel'y in. response to :such lateral, move-e q@ each xegntrg11ed V"Stati-,ion :operativ-@1y connected, to- 2t the control line and to the motor and'adapted to be connected to a source of motor driving fluid under higher pressure, means responsive to actuation of the motor for actuating said cross connecting valve to increase the pressure in the control line by connecting the source of motor driving uid to the control line, a plurality of diverting devices at the control station, one connected to each of said control lines, an actuator movably supported at the control station for successively actuating each of said diverting devices, said actuator including latch means operatively engageable with and releasable from said diverting devices, and a latch releasing element actuatable by and in response to increase of pressure in the control line.

12. In a system as dened in claim 11, a manually movable member appurtenant to each of said diverting devices for preventing actuation thereof by the actuator.

13. A system as dened in claim 11 wherein each of said latch releasing elements is iiuid actuatable and connected to one of the control conducts and each of said diverting devices comprises a diverting valve normally venting the control conduit and also venting the latch releasing element but movable by said actuator to close the vent.

14. A system as defined in claim 11 wherein each of said latch releasing elements is fluid actuatable and connected to one of the control conduits and each of said diverting devices comprises a diverting valve normally venting the control conduit and also venting the latch releasing element but movable by said actuator to close the vent and connect said conduit to the source of control fluid.

15. In combination with a system as defined in claim 14, a time delaying device connected between said source of control fluid and said diverting devices.

16. In combination with a system as dened in claim 14, a pressure-responsive cut-off valve connected between said Source of control fluid and said diverting devices and responsive to a fall of pressure of said source of motor driving iiuid to interrupt the flow from the control fluid source.

17. A sequence controller for a plurality of soot blowers incorporated in a system which includes a controlled station for each soot blower and a common control station, a control line connecting the control station to each controlled station, a plurality of controllers at the control station, one such controller being connected to each control line, said controllers being arranged in spaced relation to one another and individually actuatable to control the connection of said control lines to a source of power, and a single common traveling actuator at the control station and movable to sequentially operatively engage each of said controllers.

18. Means as defined in claim 17 including means defining a predetermined path of travel for said actuator, said controllers being arranged upon opposite sides of said path of travel and in staggered relation to one another for successive actuation by the actuator.

19. Means as set forth in claim 17 wherein each of said controllers includes a portion operatively displaceable by the actuator, and individual diss abling means appurtenant to each controller for preventing actuation of the controller by the displaceable portion.

20. Means as set forth in claim 17 wherein each of said controllers includes a portion operatively displaceable by the actuator, and individual means for retracting each of said displaceable portions to an inoperative position with respect to the actuator.

21. Means as dened in claim 17 including means independent of the remainder of said system for driving said actuator.

. 22. Means as dened in claim 17 including a control panel having a slot therein corresponding to the path of travel of the actuator, the actuator being arranged to travel behind the panel, and a combined actuating and indicating handle connected to said actuator and extending through the slot and accessible from the front of the panel.

23. Means as dened in claim 17 including a substantially vertical panel at the control station having a slot therein corresponding to the path of travel of the actuator, the actuator being biased to move toward one extremity of the slot, means for moving the actuator in the opposite direction against the eiort of the biasing means, and an indicatorportion movable with the actuator and visible through the slot.

24. Means as defined in claim 23 wherein said indicator portion includes a handle projecting through the slot and accessible from the front of the panel and by which the actuator may be moved.

25. Means as defined in claim 17 including a master controller connected in series with said rst-mentioned controllers, and an actuating portion for said master controller located near one extremity of the path of travel of the actuator and also actuatable by said actuator.

26. Means as dened in claim 17 wherein said controllers comprise diverting valves and said source of power comprises a source of fluid under pressure, time delay means interposed between said source and said controllers, a starting valve, an actuating portion for said starting valve located near one extremity of the path of movement of the actuator and operable in response to movement of the actuator to a starting position substantially at said extremity of its path of travel, and means responsive to operation of said starting valve for initiating action of said time delaying means.

27. In a sequence controlling system for a plurality of fluid-operable soot blowers including a controlled station appurtenant each such blower and a common control station for all of said controlled stations, means for connecting the control station to a source of control uid under pressure, a fluid pressure operable driving motor for each blower appurtenant to each controlled station, means for connecting each such motor to a source of higher pressure motor driving uid, diverting means at the control station for selectively directing the control iluid to predetermined controlled stations to regulate the action of the several blowers, said diverting means including a plurality of valving portions, a control conduit for connecting each such valving portion to one of the controlled stations, means including a cross-connecting valve at each controlled station operable by the appurtenant motor to effect a temporary cross connection between the higher pressure motor fluid supply source and the control line, and diverter actuating means at the control station connected to the control line and responsive to increased pressure therein to operate said valving portions.

28. A system as defined in claim 27 wherein 23,v said valving portions are xedly positioned and saiddiverteractuatingV means'comprises a travelingatatr movable to sequentially operatively.

engage' said Valving portions, latch-type actuating abutment portions carried partly by said actuator and partly by said valving portions and interen-v ga'geabl-to arrest the actuator during actuation of eaclfi valving portion, said diverter actuating means also including latch releasing means operabl'elby'such increased pressure in the control conduit to release said abutment portions from interengagement, travel of the actuator being arrested by( and during such nterengagement but permitted Vby such release.

29,..Me`ans as dened in claim 28 including driving means tending to move said actuator in one direction in which said abutment portions may successively operativly interengage one another; saidlactuatorfbein'g movable in an oppo` site direction during Whichrmovement said latchtype'abutment portionsmay move past one another without sucharresting interengagement CURTIS L. Hou/SE.

RLFEIENoEs CITED The` followingrefeigences are of record in the file of this patent;

UNITED zSTA'IVES PATENTS

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