US2825923A - Control system for soot blowers of the puff type - Google Patents

Description

March 11, 1958 LE ROY 9. DE MART 2,825,923

CONTROL SYSTEM FOR SOOT BLOWERS OF THE PUFF TYPE 4 She e ts-Shee t 1 Filed Feb. 21, 1952 IllllLlLlU IN V EN TOR.

March 11, 1958 LE ROY 5. DE MART 2,825,923

' CONTROL SYSTEM FOR $001: BLOWERS OF THE PUFF TYPE Filed Feb. 21, 1952 4 Sheets-Sheet 2 1N VEN TOR. Z67 5.20am? wi V5.

- CONTROL SYSTEM FOR SOOT BLOWERS OF THE PUFF TYPE Filed Fb. 21. 1952 March 11, 1958 LE ROY 5. DE MART 4 Sheets-Sheet 3 March 11, 1958 LE ROY 5. DE MART 2,82 2

CONTROL SYSTEM FOR SOOT BLOWERS OF THE PUFF TYPE Filed Feb. 21, 1952 4 SheetsS heet 4 E1 INVENTOR.

BY 7 430 714mm, 2%

Patented Mar. 11, 1958 CONTROL SYSTEM FORSOOT BLOWERS OF THE PUFF TYPE Application February 21, 1952, Serial No. 272,770 6 Claims. .(Cl. 15-318) The present invention relates to cleaning systems of the soot blower type such as are employed to clean the heat exchanging surfaces of boilers and other heating devices. The invention is particularly concerned with soot blowing systems of the so-called pufi-type, wherein the blowing medium, which is commonly air, is dischargedagainst the surfaces to be cleaned in a succession of relatively short blasts.

An important object of the invention is to provide a simple, inexpensive, and reliable automatic control system for a plurality of puff-type soot blowers, the system utilizing very few mechanical components.

A further object is to provide such a control system which is adapted for use in conjunction with master control mechanisms such as are disclosed in Howse Patent No. 2,565,689 granted August 28, 1951, and in Rose appli cation, Serial No. 153,093 filed March 31, 1950, and now Patent No." 2,620,632, which incorporates novel means for automatically controlling the duration of the individual blasts of cleaning medium, such means being easily adjustable to vary the length of the blasts.

Still another object is to provide improved sequence controlling means for automatically and individually instituting and terminating the operating cycles of a plurality of puff-type soot blowers, which may, with my improved system be made to operate-in a desired sequence, while individual units,at the will of the operator, may be bypassed or left out of the sequence of operation without disturbing the operation of other units.

Still another object is to provide an improved secondary control system adapted to coact with a master control system such as is disclosed in the aforementioned Howse patent or Rose application in such manner as to cause the master control system to shut down all of the blowers governed by thesecondary system after completion of the operating cycles of all of the puff blowers incorporated in the secondary. system.

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 the principles of the present invention;

Fig. 2 is a substantially diametric longitudinal, sectional view of a soot blower head of the puff type adapted to becontrolled in accordance with the'present invention; i

Fig. 3 is a cross-sectional view taken substantially on the line 3-3 of Fig. 2 and looking in the direction of the arrows;

Fig. 4 is a plan view of the soot blower head;

Fig.5 is a fragmentary sectional detail taken substantially on the line 5-5 of Fig. 2 and looking in the direction ofthe arrows; 7 v I Fig. 6 is a longitudinal, vertical, sectional view, taken on the line 66 of Fig. 8 of a sequence valve of atype employed in my improved system; t 1

Fig. 7 is a plan view of the sequence valve; and

Fig. 8 is a side elevational view of the sequence valve.

Referring now to the drawings, Figs. 2, 3, 4 and 5 i1- lustrate a puif-type soot blower of the character adapted to be controlled by my invention. Reference character 20 designates a blower nozzle tube element, which is only fragmentarily illustrated since its precise construction forms no part of my present invention. The nozzle tube element is preferably a straight tube rotatable about its longitudinal axis and'provided with discharge orifices as 21 located along one side only, so that the blast therefrom may be discharged in desired directions by rotating the unit, and by controlling the admission of the cleaning fluid, it may be directed only toward those portions of the boiler or other heating installation assigned'forcleaningto the particular blower unit under consideration.

The admission of the cleaning fluid (which will be referred to as air although this is of course a matter of choice or judgment under the conditions prevailing) is controlled by valving means presently to be described. It is desirable to admit-the cleaning fluid in relatively short blasts or puffs, since soot, slag,,and other deposits are more efiectively removed in this manner, and the same valving means may be used to achieve this action. l

The nozzle tube 20 is constructed to be mounted ina position in which it projects through a boiler wall as 23. It is preferably attached by a floater 24 resiliently mounted as by means of studs 25 and springs 26 and 27 'upon the flange 28 of the wall box 29. Floater 24 carries a packing gland generally designated 30, and the floater, packing gland, and nozzle tube are universally movable with flexure or distortion of the. nozzle tube. To permit such movement, enlarged holes as 31 are formedin the portions of the floater through whichthe studs 25 project. Springs 26 are trapped between the body of the floater and the stud nuts 32 and tend to hold the floater against the flange 28 and the nozzle in the position thus determined, while lateral movement of the floater and the nozzle are yieldably opposed by the spring 27 which, in the shown installation, urges the nozzle and head assembly upwardly, tending to maintain it in the upper most position which its vertical travel permits.

Fast upon the nozzletube 20.near its outer end is a ratchet wheel 40 by which the tube and the nozzle orifices therein may be rotated, through .the agency of a jacking motor mechanism presentlyto be described. The ratchet wheel-and associated parts are enclosed in a head housing 50 which is held against rotation by studs 51, anchored in. flange 2S, and projecting through enlarged slots :52 formed in the front flange 53 of the housing. Rotation of the head is also opposed bythe supply pipe assembly and inlet casting 6t). A thrust bearing 58 of the ball type is carried on the nozzle tube within casing 50 between the hub 41 of ratchet wheel 40 and the front of the casing. Axial movement of the head and nozzle assembly as a unit is limited by a pair of washers54 mountedupon each of the studs 51 and one overlying each side ofthe flange 53, the washers being held in spaced relation, farther apart thanthe thickness of the flange 53, bya spacer bushing 55 located between the washers uponthe stud and held, as are the washers 54, by nuts 56 and 57..

The outer end of the tube 20 is fitted into the inlet casting 60 and sealed with respect thereto as by means of the packing gland 61. The packing gland 61 preventsescape of blowing air into the interior of casing 50, as will be apparent. The inlet casting 60 forms a continuation of casing 50, to which it is tightly joined bymachine screws 62. Casting 60 is provided with an inlet passage to be connected as by pipe 158.

-Communication between the inlet 65 and the nozzle tube -is controlled by a main blow valve 67 mounted for vertical movement in the casting and opening against inlet pressure. The blow valve is fast upon a guiding stem assembly 68 slidable in top and bottom slide bearings 71, 72 in the casting. A coil compression spring 69' arranged upon the valve stem beneath the valve, in a suitably chamhered portion of the casting, urges the valve upwardly toward closed 'position. The upper extremity of the valve stem projects through the bearing-71in the upper wall of the casting 60 and into a cylinder mounted upon the top of the casting coaxially-with the valve stem and containing a valve-actuating piston 73 to which-the stem is attached. The lower end ofthe cylinder-is vented as indicated at 77, while an inlet port 74 is provided in the head 75. It will be noted thatthe areaof'the piston exceeds that of the valve 67. The pressure ofthe motivating air supplied to the cylinder 70 through the port 74 is ordinarily the same as that of the blowing air supplied through the inlet 65, and the relative areas of the piston and valve are such that the openingeifort generated within the cylinder is sufiicient to overcome the closing elfort exerted upon the valve 67 bynthe combined effect of the supply pressure and the spring 69. V

-Actuating aircan be supplied to the cylinder 70 only when. a blowcontrol valve 81 (Fig.- 3) contained in a valve casing is held open by -a cam 85 which acts upon the valve through a pivoted-follower trigger 86 and an elongated valve stem-87 attached to the valve. The actuating cam 85 is attached to one face of the ratchet wheel 40 and maybe in the form of a concentric cylindrical flange. The trigger 86 is pivoted in a pair of lugs depending from a hanger bracket 88 attached to the topwall of the housingStlby the threaded lower end of the valve casing 80, which is screwed into a suitably tapped opening 1n the top wall of housing 50 and so located that the valvestem 87 which projects-downwardly through the valve casing and into housing 50 is aligned with and actuatable by the trigger when the latter is lifted by the camp. The cam is cut away in the areas corresponding to thosetangularpositions of the nozzle tube element in WhlCll blowing is not desired, to allow the trigger to drop, at which time the valve 81 falls to closed position, gravity being assisted by the spring 89 located Within theflvalve casing above thevalve and acting downwardly thereupon. When the valve israised, communication 1s established between an air supply conduit 90'and a tube 91 leading from the valve casing to cylinder 70. With the shown cam arrangement, the air supplied through conduit 90 pulsates at arate more rapid than the frequency of openingand closing of-valve 81 by the cam 85, and the piston .73 is thereby moved up and down to openand close valve.67 at a rate which admits the blowmg a1r1n puffs of desired duration and frequently. The means for providing and regulating the puffs will presently..be described..- It will also be appreciated that the cam 85 may be of any desired angular length corresponding to-the desired blowing arc, and may be an uninterrupted ring if it is desired that the blower act throughout 360.-

- The valve casing 80 also serves as a coupling for a conduit 92 which leads to a jacking motor cylinder 95 mounted upon the side of casing 50 with its axis vertical and in alignment with the extended plane of the ratchet wheel 40. It will be noted that conduit 92 is in constant communication with conduit 90 via the upper portion of the valve casing 80. Within the cylinder 95 is a reciprocablepiston 97 having a stem structure 98 which carries a ratchet-actuating or jacking pawl 99. The lower end of the-stem structure comprises a rod journaled in a bearing 100 carried by the lower wall of a lateralextension 101 of housing 50, within which extension the stem structure travels carrying the pawl 99 in a path substantially tangential with respect to the ratchet wheel,

into operative enga ement with which the pawl is urged by a torsion spring 102. An antibacking pawl 103 is preferably also provided, pivoted upon a fixed axis in the casing 50 and engaging the ratchet wheel 40 to prevent it from being moved in a reverse direction by the drag of pawl 99 upon the return stroke of the latter, or due to torsion resulting from resistance of the element to rotation.

The jacking piston and pawl assembly is urged downwardly by air pressure and returned by a spring 105, trapped upon the lower rod portion of the stem and also encircling the upwardly elongated bearing boss 100. The boss 10!) serves as an abutment within the housing extension 101 to limit the downward travel of the stem. pawl and connected piston. The upper section of the stem structure is formed as a bifurcated casting, between the legs of which the pawl 99 is pivoted. A guide screw 106 projects from the side of the valve stem into a slot 107 in the casing extension 101 to key the piston, stem, and pawl assembly against rotation and to provide means whereby the action of the jacking motor assembly may be observed.

The jacking motor intermittently rotates the ratchet wheel 40 ,and turns the nozzle element 20 so long as the pulsating air. supply is furnished from the control system presently to be described. In the shown construction the arrangement and travel of the pawl and piston are such as to actuate the ratchet wheelsthrough the angular distance of two teeth upon each stroke of the piston.

In order to, prevent the gases of combustion within the boiler from backingv up. during the idle periods of the blower unit, or frornfiowing out under the positive pressure frequently employed in modern boilers, and finding their way through the nozzle tube 20 and into the head and inlet casting, a source of fresh air is piped to the nozzle head,.as by means, of the conduit 110, which conmeets the interior of the inlet casting 60 at a point beyond the mainyalve 67 to a sourceo f fresh air under relatively low pressure, An inwardly openingcheck valve 112'is incorporated in line 1 10, and the fresh air is fed therethrough to the unit to provide an outflow through the nozzle orifices at all times when the valve 67 is closed. When valve 67 is open and the head is under blowing pres sure, check valve 112 closes, preventing escape of blowing air through the conduit 110'; If the boiler is of the type having an outer jacket as 23 spaced from the inner wall 23 to define a space within which positive air pressure, ismaintained, the purging air may be derived simply by coupling the conduit 110 directly to the outer jacket as indicated at 111, although any other suitable source may of course be employed. v v

It will beappreciatedthat a boiler installation normally includes a plurality of blower units, each having its own head construction and several or all of which may be of the general class of the unit just de'scribedu The blower units or heads are locate dat such'points throughout the boiler or other apparatus tobe cleaned that by operation of all the units, cleaning ofgt he entire boiler or other heating apparatusmaybe effected. In orderto permit such cleaning without requiring delivery of an undue volume of air, it is desirable that the several cleaning units located throughout the boiler be operated in sequence rather than: simultaneously. This also permits the progressive cleaning;of the boiler, by using first those blowin'g unitsinost remote from the stack and then so quentially energizing those closer to the stack so that the soot, slag, and other dislodged fouling material may be carried forwardly in the direction of travel of the flue gases, and then discharged through the stack. The means for controlling the operation of the several blowers of the system preferably includes a master control panel generally designate d 1 50 constructed and adapted to operate in accordance with the disclosure of the aforementioned Howse Patent No. 2,565,689, "or in accordance with the disclosure of Rose application, Serial No.' 153,093, filed March 31, 1950. Such control panels and master control systems have become well known in the art. e e T he control panel 150 is connected by a conduit 152 to the actuating diaphragm chamber 154 of a diaphragm valve 155. The control panel may control the sequence of operation of a number of other blowers or devices'not shown herein, and each blower, or each group of blowers. as the case may be, is connected to the control panel by a conduit corresponding to the conduit 152, a plurality of such other conduits being shown connected to the panel, but broken off close to the panel and typified by those designated 156. The panel is arranged to control the starting and stopping of the entire secondary control system herein disclosed, and by way of illustration the secondary control system is shown as encompassing three blowers of the puff-type hereinabove described. In the diagram- 'rnatic view, Fig. 1, such blowers are designated I, II and III. When, in accordance with the operation of the control panel, the puff-type blowers, I, II and III, are to be operated, the control panel delivers air under pressure through the control conduit 152 to the chamber 154. This air may be under a relatively low pressure, as for example, p. s. i. The control panel is so constructed that if the pressure in the control line is raised to a substantially higher pressure, as for example, p. s. i., a

trip-out mechanism carried by thecontrol panel will be actuated to disconnect the 35 p. s. i. pressure supply from :the conduit 152, and vent the conduit 152 so as to discharge therefrom the. 80 p. s. i. air. As will be hereinafter explained, this results in a shutting down of the sec: ondary system governed by the control conduit 152.

All three of the blowers I, II and III, are connected as by means of suitable piping 158, to a source of blowing airunder pressure, the supply piping being connected to the several blowers at the inlet chamber portions 65 thereof. Also connected to the blowing air supply line is a conduit 162 which supplies air to the puff generating and sequence control mechanism of the secondary system and to the blower rotating means and blow valve actuating-rneans (previously described) of the blowers I, II 'and III.

The conduit 162 is connected by means of a branch conduit 164 to the diaphragm valve 155 and is also connected to another diaphragm valve 165. .From

the diaphragm valve 155 a conduit 166 leads to an adjustable orifice valve 168 which is in turn connected by a .conduit 170 to a tank 172. The tank is connected by a conduit 174 to the actuating diaphragm chamber portion 175 of a pressure operated valve, the valve assembly portion of which is designated 176. Tank 172 is also conjnected by conduit174 and branch conduit 177 to the valve 176,.and a conduit 178 leads from the valve 176 to the actuating diaphragm chamber 180 for the diaphragm valve 165. Also connected to the chamber 180 is an adjustable orifice vent valve 182. The valves 155 and 165 are of a well known type which is urged to closed position by suitable spring means and adapted to be opened by fluid under sufficient pressure delivered to the diaphragm chamber. The valve 155 is so biased that it will be opened when air at the reduced pressure (e. g. 35 p.;s. i.) is delivered thereto through control line 152,

although the diaphragm mechanism will withstand the higher pressure (e. g. 80 p. s. i.) without injury and the ,valve will remain open until the pressure in the chamber 154 drops below 30 p. s. i. The pressure operated valve rnechanism 1'75, 176 is also of a well known and commercially available type which imparts a snap action to the valve 176, causing the valve to open suddenly when i the pressure in the actuating chamber portion 175 rises to a determined value, and to close quickly when the pressure in portion 175 falls to another predetermined value I which is substantially below the pressure required to open 7 the valve. The orifice valve 182 is so set that its effective cross section is greater than that of the orifice valve 168. f The output side of the diaphragm valve 165 is con- "nected by a conduit 184 to a sequence control valve, the

6 construction of which is shown in detail in Figs. 6, 7 and 8 and the casing of which is generally designated 185'. The sequence control valve casing 185 is supported as by means of a suitable bracket 186 on the frame portion 50 of the blower head. The casing 185 may, as shown, be of rectangular cross section, vertically elongated, and provided with a smooth walled internal chamber 188 in which a valve member 190 is slidable. Attached to the valve member is a stem 192 which extends slidably downwardly through the lower head 194 of the valve casing. A helical compression spring 195 normally holds the valve at the upper limit of its path of travel in the casing.

When the valve portion 190 is in the'raised position, a valving portion shown as a resilient pad 196 carried by the upper extremity thereof closes a port 198 formed in the upper head plate 200 of the valve casing. The head plate 200 is also provided with a coupling portion 202 for a conduit 204 which leads to a suitable fitting (undesignated) on the side of and opening into the interior of the blower inlet chamber 65, so that coupling portion 202 is always in communication with the source of blowing air supply. The port 198 through which the coupling portion 202 communicates with the chamber 210 above the valve 190 is of such reduced cross section that the blowing air pressure cannot force the valve down against spring 195 and unseat the pad 196 when the pad is in engagement with the orificed portion 198. If the valve is unseated however, the pressure, which is then exerted on the entire top of the valve element 190, is enough to hold the valve element down against the bias of spring 195. The valve casing 185 is also provided with a side port 212 near its upper end in constant communication with the chamber 210.. Port 212 is connected by a branch conduit 214, through a normally closed hand valve 215 to the conduit 204, so that by opening the hand valve, blowing air pressure is directly introduced into chamber 210 to force the valve element 190 down and/or hold it down. This is a bypass condition in which the blower head (I) connected to such valve cannot be actuated. The valve element 190 is keyed against rotation as by a screw 216 which projects into a keyway 218 in the side of the valve element.

The line 184 is connected to an air inlet port 220 located approximately midway of the length of the' valve casing 185, and in transverse alignment with the port 220 is a port 222 shown as coaxial with the port 220 and located on the other side of the valve casing. Also located on the same transverse plane as the ports 220, 222 is a port 224 the axis of which is at right angles to the ports 228, 222. The valve is a two position valve and is shown in its up position in Fig. 6. In such position an angular passage 225 in the valve element 190 connects the port 220 to the port 224. When the valve element is in its down position another valve passage 226 provides communication between the ports 220, 222. Suitable sealing means, shown as an O-ring 228 carried by the valve element between the passage 226 and the upper end of the valve, prevents pressure communication between the ports 220, 222, 224 and the chamber 210.

The manner in which the sequence valve 185 is mounted on the head of its blower unit is shown in Figs. 2 and 4 and as indicated in Figs. 5 and 6, a transverse plate 230 is fast upon the projecting lower end of the stem 192. The plate 230 is so positioned as to lie beside the periphl e'ral portion of the casing 50 which houses the ratchet 1 wheel 40. A rockable shaft 232 is journaled in the casing '50 and projects therethrough beside ratchet wheel 40 in such manner that these parts do, notinterfere. On its outer end beside and directlyoverlying the plate 230 on either side of the stem 192, the'shaft 232 carries a pair of pins 233, 234 secured in a disk 235 fast upon the end of the shaft 232. Within the casing 50 and projecting beside the ratchet wheel 40, the rock shaft 232 carries fast thereupon an arm 236, and a lug pin 238 fast in the wheel 40 is adaptedto strike the arm 236 to rock the shaft 232 eam 1 .7 v -v- I f M- when Ithetwheel 40-,carries the lug pin into engagement with thearm. ..The arm is so shaped that the lug canmove underand freely past the .arm,;but rocks the arm and shaft .232-.far enough so that the. pin 233 or 234, as the case may. .be,-moves ,the,stem 192 and valve 190 downwardly far cnoughto separatethe valve, pad 196 from the orifice198, so that,.assuming that the valve 215 is in its normal closed condition, blowing air pressure is then admitted to the chamber ,210 and such pressure drives the valve 190 to, and holds it in, the lowermost position, wherein valvepassage 226 connects the ports 220, 222. It will be understood thatthe employment of the two pins 233, 234 not only maintains the rock shaft and arm, 236 in proper position, but that such soot blower heads are sometimes rotated clockwise and sometimes counterclockwise so that with the parts constructed as shown they will function equally well regardless of the direction of rotationof the unit: .The conduit 90 is connected as by coupling means 240 to the port 224. As previously explained, the conduit 90 conducts the driving motor air through the valve means contained in the casing 80 and the conduits connected thereto, to the jacking motor cylinder 95 and the blow valve actuating cylinder 70.

. The port 222 is connected as by means of a conduit 242 to an inlet port (corresponding to the port 220 but not specifically designated) of a sequence valve 185 which. may be identical in construction to the valve 185 already described and which may be similarly mounted on and adapted to control the action of the second blower head. The sequence valve 185 is similarly connected to the head II as by conduit means 90 204 and the outlet port of the valve 185 (which port is not shown in detail but corresponds to the port 222) is connected as by a conduit 244 to the inlet port of the sequence valve 185 of the next head III. Sequence valve 185 issirnilarly connected as by conduit means 90 and 204 to the blowing head III. The head III is illustratively presumed to be one designed to blow throughout 360, so that no valve means, corresponding to that contained in the casing 80, is required, and the conduit 90 is directly connected to the jacking motor cylinder and to the blowvalve as by branch conduits 92 and 91 respectively.

It is illustratively presumed that the head III is the last of the series to be controlled by the secondary control system. The outlet port of the sequence valve 185 (which port corresponds to the port 222) is therefore connected as by a conduit 245 in such manner as to cause the master control system at the control panel 150 to induce closure of the diaphragm valve 165 and shut down all of the heads (I, II, III) of the group. In my preferred arrangement, this action is achieved by connecting the conduit 245 through a check valve 246 and an orifice member 248 to the control line 152. lustrative arrangement shown, the branch conduit 250 from the orifice member 248 is connected to the diaphragm chamber 154 of the diaphragm valve 155 to which the control conduit 152 is also connected. ,The check valve 246 opens in a direction to permit. air flow from the final sequence valve 185 through the orifice and diaphragm chamber 154 to the control line but does not permit flow from the control line to the sequence .valve. ,A storage tank 252 is connected by a conduit 254.. to the conduit system previously described at a pressure in the tank 172 reaches a predetermined value,

In the ilit acts through-the actuating portion 175 to cause the pressure actuated valve 176 to snap open, and air passes therethrough and. is delivered by, conduit 178 to diaphragrn chamber 180, causing diaphragm valve 165'to open so that air will then be delivered through conduit 184. to the inlet port 220 of sequence valve 185' and through such valve-via passage 225, port 224, conduit 90, valve body 80, and conduit 92 to the jacking motor actuating means. One actuating stroke is thereby imparted to the jacking motor piston 97 and if the valve element 81 is in the raised position, air is also delivered through conduit 91 to cylinder and the blow valve is also actuated to deliver a blast of cleaning fluid through and from the nozzle tube 20. The blast of cleaning fluid continues while the pressure falls away in the diaphragm chamber 180 due to the fact that the orifice in member 182 is larger than the orifice in member 168. The valve remains open however until the pressure in the. tank 172 and in the actuating diaphragm portion 175 of pressure actuated valve 176 falls below a critical value at which the valve 176 snaps closed. The pressure in chamber 180 then falls rapidly and the valve 165 closes, terminating the puff and allowing the pressure to. drop in the valve body 80 and connected portions of the system. The jacking piston 97 is then raised by the spring 105 and the blow valve 67, if it was open during such impulse, is then closed by the spring 69. As soon as the pressure again builds up in tank 172 and chamber 175, the valve 176 again snaps open, valve 165 is opened, andpressure is again delivered to actuate the jacking motor to turn the ratchet wheel 40 and blower nozzle tube through the distance of another ratchet tooth, and also to open the blow valve if the valve 81 is open, as previously indicated. 'This action continues until the ratchet wheel-40 rotates to a position such that the lug 238, through the mechanism previously described, trips the sequence valve member 190 causing the latter to be moved down by the delivery of blowing air pressure to the chamber 210, so that the sequence valve interrupts communication between conduit 184 and conduit 90 and air can no longer be delivered either to the jacking motor. cylinder or the blow valve actuating cylinder of head I. The sequence valve then conducts the pressure delivered thereto via conduit 184 directly through the valve by way of port 220, passage 226, port 222 and conduit 242 to the sequence valve 185 of head II. The same action occurs in the operation of head II, the valve member of the first sequence valve 185 being held down by blowing air pressure throughout the operating cycle of the blower head II. After head II has run through its complete cycle in similar manner, its sequence valve 185 is tripped and moved down to the by-pass position in similar manner, and held down by blowing air pressure so that the air is delivered through both sequence valves 185, 185 and via conduit 244 to sequence valve 185 which similarly initiates, and delivers air for, actuation of the blow valve and actuating piston of head 111.. Head III then runs through the same cycleof intermittent putt-type blasts of blowing medium and intermittent rotation until at the completion of its rotation, valve 185 is moved down to the by-passing position whereupon the air is delivered back through conduit 245 and check valve 246 and orifice 248, conduit 250 and chamber 154 to the control line 152. As previously indicated the pressure delivered in this manner may be higher than the normal control line pressure and of the order, for example, of 80-100 p. s. i. As soon as this pressure has built up sufficiently in the tank 252 .to deliver. a sufliciently increased pressure to the control line 152, the trip-out mechanism at the master :control panel 150 disconnects the conduit 152 from the source of controlair supply and opens line 152 to attained therein through the orifice 248, and valvey155 resultantly closes. It may require several puffs to fill the tank 252 at the higher pressure, delivered thereto through the conduit 245, but the tank is thereafter capable of delivering the higher pressure air in suflicient volume to effect the trip-out action. The construction and operation of the control panel trip-out mechanism form no part of my present invention and have become known in the art as previously stated. When the entire series of blowers has run through its cycle of operation, and the source of blowing air supply to the line 160 is cut oif, the valve elements 190 of valves 185 are no longer subjected to blowing air pressure, and are lifted and automatically reset by their springs 195.

While it will be apparent that the preferred embodiment of the invention herein described is well calculated to fulfill the objects and advantages first above stated, it will be appreciated that the invention is susceptible to variation, modification and change without departing from the fair meaning and proper scope of the ap pended claims.

I claim:

1. Means for controlling the action of a plurality of pufitype soot blowers of the type having individual blow valves through which each blower is adapted to be connected to a source of blowing air supply, including a plurality of servomotors, one such servomotor being appurtenant to each of said blow valves, a plurality of sequence valves, one appurtenant to each of said servomotors, said sequence valves being connected in series with each other, a first one of said sequence valves being connected to a source of fluid under pressure for actuating said servomotors, a pressure operable valve interposed between said first sequence valve and said lastmentioned source, pulse generating means for actuating said pressure operable valve, said first sequence valve being movable to direct fluid from said last-mentioned source either to the servomotor of a first blower or to divert the fluid therefrom to a subsequent sequence valve, and the last sequence valve of the series being movable to direct such fluid either to the servomotor of the last blower or to other fluid conducting means, additional actuating means for said pressure operable valve connected to said other fluid conducting means to close said pressure operable valve in response to delivery of fluid through said other fluid conducting means, and means responsive to completion of the operating cycle of each blower for actuating the appurtenant sequence valve to its diverting position, whereby fluid from said source is delivered to said additional actuating means for the pressure operable valve after completion of the operating cycle of the last of said blowers.

2. Means as defined in claim 1 including means for activating and deactivating the pulse generating means under the influence of a master control system or the like, said other fluid conducting means being connected to said means for activating and deactivating the pulse generating means, an accumulating chamber portion also connected to said other fluid conducting means, and a restriction element interposed between the point of connection of said chamber portion and said means for activating and deactivating the pulse generating means.

3. Means as defined in claim 1 including means for activating and deactivating the pulse generating means under the influence of a master control system or the like, said other fluid conducting means being connected to said means for activating and deactivating the pulse generating means.

4. Means as defined in claim 1 wherein said pulse generating means comprises a timing chamber connected to a constant fluid pressure source, an automatic valve interposed between said timing chamber portion and said last-mentioned source, actuating means for said automatic valve, said actuating means being adapted to be I i mi connected to a control line and operable to open said valve in response to pressure in the control line, a restriction portion interposed between said automatic valve and said timing chamber portion, means including a quick acting pressure responsive valve connecting said timing chamber portion to said first-mentioned pressure operable valve, said quick acting valve being operable to open and closed positions in response to increase and decrease of the pressure in said timing chamber portion above and below predetermined pressures, and a vented restriction portion of greater eifective cross section than said previously mentioned restriction portion connected to the actuating portion of said first-mentioned pressure operable valve.

5. In combination with a plurality of soot blowers each of which is operative through a predetermined cycle, and a source of blowing fluid supply, a blow valve appurtenant to each blower for controlling the discharge of blowing fluid therefrom, servomotor means appurtenant to each blower for actuating the same and for actuating the blow valve appurtenant thereto, means for controlling the connection of the servomotor means for each such blower to a source of power for said servomotors and including a power diverting sequence mechanism appurtenant to each blower, each such mechanism being operable by the blower to which it is appurtenant as the blower completes its predetermined cycle, said several sequence mechanisms being connected in series with one another and with said source of power and each of said mechanisms except the last thereof being movable to two positions, in one of which it delivers power to said servomotors and in the other of which it delivers the power to the next succeeding diverting mechanism of the series, a shut-off device for preventing delivery of power from said source to the first diverting mechanism of said series, means connected to the last diverting mech anism of said series for actuating said power shut-off device in response to actuation of said last diverting mechanism, and pulse generating means connected to said shut-ofi device for periodically opening and closing the same.

6. In combination with a plurality of soot blowers each of which is operative through a predetermined cycle, and a source of blowing fluid supply, a blow valve appurtenant to each blower for controlling the discharge of blowing fluid therefrom, servomotor means appurtenant to each blower for actuating the same and for actuating the blow valve appurtenant thereto, means for controlling the connection of the servomotor means for each such blower to a source of power for said servomotors and including a power diverting sequence mechanism appurtenant to each blower, each such mechanism being operable by the blower to which it is appurtenant as the blower completes its predetermined cycle, said several sequence mechanisms being connected in series with one another and with said source of power and each of said mechanisms except the last thereof being movable to two positions, in one of which it delivers power to said servomotors and in the other of which it delivers the power to the next succeeding diverting mechanism of the series, a shut-off device for preventing delivery of power from said source to the first diverting mechanism of said series, means connected to the last diverting mechanism of said series for actuating said power shut-off device in response to actuation of said last diverting mechanism, and pulse generating means connected to said shut-oi? device for periodically opening and closing the same, an interrupting device for disabling said pulse generating means, said last diverting mechanism of the series being connected to said interrupting device to disable the pulse generating means in response to actuation of said last diverting mechanism.

(References on following page) 12 References Cited in the file of this patent 2,327,524 Hibngar et a1 Aug. 24, 1943 i 2,462,614 "DeWitt Feb. 22, 1949 UNITED STATES PATENTS, .2 2,4 3,655 (316mb Jan, 1 5 1,991,963 J m 19, 3 2,553,044 H w May 15, 1951 2,049,421 Bretsford et a1 Aug. 4, 1936 5 2,065,144 Miller et a1. Dec. 22, 1936 FOREIGN PATENTS 2,240,079 Roth Apr. 29, 1941 431,352 Great Britain Jul 16, 1935 2,303,152 Weeks Nov. 24, 1942 504,917 Great Britain Apr. 27, 1939 U. 5. DEPARTMENT OF COMMERCE Y PATENT OFFICE CERTIFICATE 0F CORRECTION Patent No, 2.325923 I March 11, 1958 Le Roy 6 De Mart It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction and that the said Letters Patent eheuld read as corrected below.

Column 3 line 55, for "frequently" reed frequency Signed. and sealed this 6th day of May 1958.

(SEAL) Attest;

KARL MINE ROBERT c WATSON Atteeting Officer Comniseioner of Patents

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