US2865042A

US2865042A - Soot blower control system

Info

Publication number: US2865042A
Application number: US575217A
Authority: US
Inventors: Mccoll William
Original assignee: Diamond Power Specialty Corp
Current assignee: Diamond Power Specialty Corp
Priority date: 1956-03-30
Filing date: 1956-03-30
Publication date: 1958-12-23
Anticipated expiration: 1975-12-23

Description

Dec.'23, 1958 w. MccoLL sOOT BLOWER CONTROL SYSTEM 3 Sheets-Sheet 1 Filed March 30, 1956 W. MCCOLL SOOT BLOWER CONTROL SYSTEM Dec. 23, 195s I 5 Sheets-Sheet 2 Filed March 30, 1956 IN VEN TOR. xfa/17721147 /Vfca ZZ BY /ZA/VW 'L' ,y fray/VZ/Sf Dec. 23, 1958 w. MccoLL 2,865,042

sOOT BLOWER CONTROL SYSTEM Filed March 30, 1956 v 3 Sheets-Sheet 3 9 erdzfe Sienna Egfr/Ss INVENTOR. MZZZM f cazz nited States soor BLOWER CONTROL srsrnivr Application March 30, 1956, Serial No. 575,217 M Claims. (Cl. -317) This invention relates to fluid heater cleaners and to liuid heater cleaner systems of the kind comprising a numberof fluid heater cleaners arranged to discharge in sequence. Modern central power station boilers commonly are fitted with considerable numbers of soot blowers or fluid heater cleaners so that sequential operation of the uid heater cleaners of the cleaning system of a boiler may take a considerable period of time. During the cleaning period, an abnormal and undesirable condition exists since the discharge of cleaning uid from a fluid heater cleaner is liable, by impeding the ow of furnace gases and thereby increasing the pressure in the furnace chamber, .to lead to undesirable consequences. In order to overcome this danger an increase in suction is necessary so that the draft losses are increased and the overall efciency of the boiler is not appreciably adversely affected. It is, therefore, desirable that the period during which the abnormal condition exists should be shortened as far as possible.

In the cooler parts of a boiler, fluid heater cleaners with rotatable blower elements arranged to work without withdrawal to retracted positions may be used, but the iluid heater cleaners for cleaning surfaces in the hotter parts of the boiler must be of the type having a blower element which may be projected for operation from an inoperative or retracted position.

An object of the invention is the provision of a fluid heater cleaner of the said type which is capable of performing its cycle of operations relatively quickly. A furtherobject of the invention is the provision of a fluid heater cleaner system including a number of huid heater cleaners o-f the said type arranged for sequential blowing in which the whole cleaning operation may be performed relatively rapidly. An additional object is the provision in such a system of simple but effective pressure fluid operated control means.

When the nature of the fluel supplied to a boiler changes, the form of deposit on the heating surfaces of the boiler may also vary and a period of blo-wing appropriate to one nature of .fuel maybe inappropriate to another nature of fuel, the deposits resulting from which may be more diicult'or easier to remove than the deposits resulting from the lirst nature of fuel. A still -atent I further object of the invention, therefore, is the provision y of a fluid heater cleaner system in which the rates of operation of the fluid heater cleaners may be controlled in a simple manner.

The present invention includes a fluid heater cleaner having a blower element arranged to be power operated and to be projected for operation from an inoperative or retracted position and to be rotated while in operative g position, rotary drivingmeans arranged through unidirectional rotation to effect projection, retraction and rotation of the'blower element and means adapted `to effect rotation of the driving means at a higher speedy during projection of the blower elementv to and retraction of the blower element from` operative position than during a l 2,355,942 Patented Dec. 23, 1958 blowing period when the blower element is in operative position.

lhe invention also includes a fluid heater cleaner havand second control valves of which the rst control valve Y is adapted to effect connection betweenthe motor and the source `of working Huid during projection of the blower element to and retraction of the blower element from operative position whilst the second ycontrol valve is adapted to effect connection between the motor and the source of working lluid through a restrictor when the blower element is in operative position and during projection of the blower element to and retraction of the blower element from operative position.

The Huid heater cleaner may be of the nature described and claimed in the specificationV of U. S. Patent No. 2,722,033. In the latter specification a cam member movable together with the blower element, when the blower element reaches operative position, actuates a pilot valve Y to effect opening of a main valve controlling the admission of cleaning fluid to the blower element. Upon retraction of the blower element from operative position the main valve automatically closes. The rotation of the blower element while in operative position is a movement to and fro through an arc. Y

The invention will now be described, by Way of eX- ample, with reference to the accompanying, largely diagrammatic drawings, in which:

Figures l to 4 are in the nature of side views showing a sequence of positions occupied, in the course of operation, by a rear portion of a soot blower spindle and the movable parts of control valves associated therewith, the

valves being shown in section;

Fig. 5 illustrates connections between control valves of a series of seven soot blowers and respective fourposition cocks, the disposition of the cocks being such` that some of the soot blowers are arranged to operate in sequence, whilst the remaining soot blowers are bypassed; and

Fig. 6 illustrates the four-position cocks set to give a different selection from that illustrated in Fig. 5 of sequentially operated soot blowers.

The soot blowers referred to in the description which.A follows are preferably of the nature described and claimed in the specification of U. S. Patent No. 2,722,033 in which a cam member movable together with the blower element, when the blower element reaches operative position actuates a pilot valve to effect opening of a main valve controlling the admission of cleaning lluid to the blower l element. Upon retraction ofthe blower element from operative position the main valve automatically closes.

The rotation of the blower element while in operative supply line 5 to the air motor 3, there are provided trst` and seco-nd control valves 7 and 9, which are arranged, as hereinafter described, so that air is supplied to the motor 3, during projection and retraction of the spindle 1, at a higher rate than when, during a blowing period the blower element is in operative position.

'The first control valve 7 includes a piston 11 disposed within a cylinder 13 and formed with rods 15 and 17 extending in opposite directions and projecting through the ends of the cylinder so that when the piston 11 occupies an intermediate position in the cylinder, first and second cylinder spaces 19 and 21 are formed respectively on oppcsite sides of the piston 11, the first cylinder space 19 including an outer section 20 of reduced diameter at the inner end of which there is provided a shoulder 22 which serves to limit outward movement of the piston 11 within the first cylinder space 19.

The effective piston area exposed to the first cylinder space 19 is greater than the effective piston area exposed to the second cylinder space 21. Thus the rod 15 which extends axially through the first cylinder space 19 is formed with an inner end part 16 and an outer end part 23 of increased diameter which is arranged to slide within a bore 25 formed in an end of the cylinder, whilst the rod 17 which extends axially through the second cylinder space 21 is formed with an inner end part 27 of increased diameter. An outer end part 29 of the rod 17 which part is of greater diameter than the part 23 of the rod 15 extends in slidable relationship through a central aperture 31 formed in a union nut 33 which is mounted on the cylinder 13 so as to define the outer end of the second cylinder space 21. Between the inner and outer parts 27 and 29 of the rod 17 there is provided a shoulder 35 which acts as a stop limiting the extent of movement of the piston 11 towards the union nut 33. A helical spring 37 disposed around the rod 17 within the second cylinder space 21 serves to bias the piston 11 towards shoulder 22 in the first cylinder space 19. It will be appreciated, therefore, that the piston 11 can move in one direction in the cylinder 13 until the piston contacts the shoulder 22 and, in the other direction, until the shoulder 35 contacts the union nut 33.

The cylinder 13 is formed with branches 39, 41, 43 and of which the branch 39 includes a bore 47 having an outer threaded section 49 and terminating at its inner end at an inlet port 51 which affords communication between the bore 47 and, depending upon the position of the piston 11, the first cylinder space 19 or the second cylinder space 21. The threaded section 49 of the bore 47 is adapted to engage a threaded nipple (not shown) at one end of an air conducting line 53 the opposite end of which opens into the air supply line 5. The branches 41 and 45 are formed with bores 55 and 57 respectively including threaded outer end sections 59 and 61, the bore 55 constituting an inlet port communicating with the outer section 20 of the first cylinder space 19 and the bore 57 constituting an outlet port communicating at its inner end with the second cylinder space 21. The bore 57 is so disposed that even when the shoulder 35 abuts the union nut 33 communication is still afforded between the second cylinder space 21 and the bore 57. The threaded outer section 59 of the bore 55 is adapted to engage an externally threaded nipple 62 at an end of an air impulse receiving line 63 through which, a signal' air pressure for initiating operation of the soot blower is conducted, as hereinafter described, whilst the threaded outer section 61 of the bore 57 is adapted to receive an externally threaded nipple 64 at an end of an air impulse transmitting line 65 through which an air signal from the second cylinder space 21 can be passed and utilized, as described below, to initiate operation of a subsequent soot blower.

The branch 43 is disposed between the branches 41 and 45 and includes a bore 67 having a threaded outer end section 69 and terminating at its inner end in a port 71 which affords communication between the interior of the cylinder 13 and the bore 67. The threaded outer end scction 69 of the bore 67 is arranged to receive an externally threaded nipple 66 at one end of an air-conducting line 73 which connects the bore 67 with the air motor 3. The disposition of the port 71 is such that when the shoulder 35 formed on the rod 17 abuts the union nut 33, air can pass from the air supply line 5 by way of air-conducting line 53, port 51, first cylinder space 19 and port 71 through the air-conducting line 73 to the air motor 3, and, when the piston 11 abuts shoulder 22 at the inner end of the section 20 of the first cylinder space 19 air can pass from the air supply line 5 by way of air-conducting line 53, port 51, second cylinder space 21 and port 71 through the air-conducting line 73 to the air motor 3. Moreover, in a range of intermediate positions, the extent of which range depends upon the axial length of the piston 11, port 51 is masked by the piston 11 so that flow of air from the air supply line 5 to either the first cylinder space 19 or second cylinder space 21 is prevented.

The cylinder 13 is formed with a further port 75, the inner end of which communicates with the bore 25 and the outer end of which is open to the atmosphere. The location of the port 75 is such that when the piston 11 abuts the shoulder 22 communication is afforded between the first cylinder space 19 an-d atmosphere by way of a passage formed between the bore 25 and an inner end part 16 of the rod 15 and the port 75. It will be appreciated, therefore, that the part 23 of the rod 15 constitutes an obturator serving, towards the end of movement of the piston 11 to the left, to uncover the port 75, thereby connecting the first cylinder space 19 with the atmosphere.

In the fully retracted position of the soot blower spindle 1, that is to say the position depicted in Fig. 1, an abutment 77 provided on the spindle 1 is arranged, through contact with the outer end of the rod 15, to hold the piston 11 in an intermediate or closed position against the biasing force of the spring 37, in which position the port 51 is masked by the piston 11 so cutting off the supply of air to the cylinder 13 from the air supply line 5, whilst an abutment 79 provided on the spindle 1 is arranged, as the spindle 1 is projected to operative position, through contact with the outer end of the rod 17 to move the piston 11 towards the shoulder 22 at the inner end of the section 20 of the first cylinder space 19 so as to uncover the port 71, thereby affording communication between the bore 67 and the second cylinder space 21.

The second control valve 9 comprises a piston 81 disposed within a cylinder 83, the piston being mounted on a rod which extends in slidable relationship through and projects outwardly beyond a bore 87 formed in an end of the cylinder. The end of the cylinder 83 opposite the bore 87 is internally threaded and is closed by means of a bolt 89 and washer 91 and the cylinder is formed with branches 93 and 95 of which the branch 93 includes a bore 97 having a threaded outer section 99 and terminates in a port 101 which affords communication between the interior of the cylinder 83 and the bore 97, whilst the branch includes a bore 103 having a threaded outer end section and at its inner end terminates in a port 107 which affords communication between the interior of the cylinder 83 and the bore 103. The section 99 of the bore 97 is arranged to receive an externally threaded nipple 98 provided at an end of an air-conducting line 109 the opposite end of which opens into the air supply line 5. The threaded outer section 105 of the bore 103 is arranged to receive an externally threaded nipple 104 provided at an end of an air-conducting line 111 which includes a restrictor in the form of a readily replaceable orifice 113 and through which air can be supplied by way of the valve 9 to the air motor 3. The valve 9 is arranged to be biased to the open position thereof, that is to say the position in which air can flow through the valve to the air motor 3 from the air supply line 5 by way of the air-conducting line 109, bore 97, port 101, cylinder 133, port 107, bore 103, air-conducting line 111 and orifice 1.13. VThus, in the retracted position of the spindle 1 the abutment 79 is arranged to hold the piston 81 in a position where the port 107 is masked by the piston, whilst air from the air supply line is available in the cylinder 83 by way of the line 109, bore 97 and port 101 to bias the piston 81 to the left. It will be aptracted position, pressure air within the cylinder 83 will act on the piston 81 moving it to the left as shown in the drawings to uncoverthe port 107 and -thereby make a supply of air available to the air motor 3 through `the air-conducting line 111.

The cylinder 83 is formed on the vlow pressure side of the piston 81 with an exhaust port 115 through which air can fiow to atmosphere from the low pressure side of the piston 31 thereby limiting resistance to movement of the piston in the direction of opening o-f the valve.

Thosev skilled in the art will appreciate that the first and second co-ntrol valves 7 and 9 could be formed in a common body, there being a common abutment provided on the spindle 1 which is adapted to engage the rod of the first control valve 7 and the rod 85 of the second control valve 9 in order, upon movement of the spindle 1 to its retracted position, to move the piston 11 and the piston 81 to their respective, closed positions. A further abutment would serve, during projection of the spindle 1 to operative position, first to allow opening of the valve 9 and then to move the piston 11 so as to uncover first the port 71 and then the port 51.

To initiate mo-vement of the spindle 1, means are provided for conducting an air impulse through the signal receiving line 63 to the valve 7. Such means include a starter valve 117 and a four-position cock 119a connected in series with the starter valve 117 between the end of the signal receiving line 63 remote from the valve 7 and the air supply line 5.

The starter valve 117 comprises a piston 121 disposed within a cylinder 123, one end of which is internally threaded and closed by means of a bolt 12S and washer 127, whilst the opposite end of the cylinder is formed with a bore `129 through which in slidable relationship with the bo-re extends a rod 131 connected at its inner end to the piston 121 and at its outer end to a knob 133. Between the piston 121 and the bolt 125 is arranged a helical spring 135 which biases the piston towards the end of the cylinder 123 opposite the bolt 125. The cylinder 123 is formed with

branches

137 and 139 of which the branch 137 includes a bore 141 having a threaded -o-uter end section 143 and terminating at its inner end at a port 145 which affords communication between the bore 141 and the interior of the cylinder 123. The threaded outer end section 143 of the bore 141 is adapted to receive an externally threaded nipple 144 provided at an end of an air-co-nducting line 147 the opposite end of which opens into the air supply line 5. The branch 139 is formed with a bo-re 149 which includes a threaded outer end section 151 and terminates at its inner end at a port 153 which affords communication between the interior of the cylinder 123 and the bore 149. The threaded outer end section 151 of the bore 149 is arranged to receive an v externally threaded nipple 152 of an air-conducting line 155 the opposite end of which is c-onnected to the fourposition cock 119a. In the' normal, closed position of the starter valve 117 the biasing spring 135 is arranged so to position the piston 121 as to cock the port 145 thereby preventing fiow of air from the air supply line 5 by way of the air-conducting line 147, bore 141 and port 145 to the cylinder 123.

In order to transmit a signal through the starter valve, the knob 133 is pressed so as to move the piston 121 to the left, as shown in Fig. l, thereby unmasking first the port 145 and then the port 153, in which position an air supply to the four-positio-n cock becomes available by way of the air supply line 5, air-conducting line 147, bore 141, port 145, cylinder 123, port 153, bore 149 and air-conducting line 155. It will be appreciated that-upon release of theknob 133 the biasing spring 135 acts to return the starter valve 117 to its closed position..

The'four-position cock 119:1 comprises-a fixed part or body 157 and-a movable part 159, ofrwhich the fixed part 157 is of square cross section and is formed with a central aperture 161 of circular cross section within which the movable part 159 is rotatably engaged. The fixed part 157 is formed with a first inlet port 163 and a second outlet port 165, the

ports

163 and 165 being aligned with respect to a diameter of the movable part 159 and disposed normal to opposite sides of the part 157. The fixed part 157 is also provided with a second inlet port 167 and a first outlet port 169,

ports

167 and 169 being aligned and extending normally to the axis of the

ports

163 and 165 and arranged to open into the aperture 161 at locations spaced apart by 120 with respect to the axis of the movable part 159. The

ports

167 and 169 are angularly spaced by 60 respectively on opposite sides of the port 163. The movable part 159 includes a main diametrically extending duct 171 and a radially extending duct 173 which is angularly spaced by 60 clockwise in advance of the duct 171.

When it is desired to pass a signal from the starter valve to the signal receiving line 63 through the cock 119a, the movable part 159 of that cock is positioned as sh-own in Fig. l so that the radial duct 173 registers with the first inlet port 163, whilst the main duct 171 registers with the rst outlet port 169.

As already intimated, an air signal is made available in the signal transmitting line 65 during operation of the soot blower and this signal can be used to initiate operation of a second soot blower. To this end the signal transmitting line 65 is connected at the end thereof remote from the valve 7 to the second inlet port 167 o-f a second four-position cock 11%, which except for the position occupied by the movable part thereof, is similar in all respects and is, therefore, similarly numbered to the cock 11911, and, the signal receiving line 63 of the second soot blower is connected to the first outlet port 169 of the second four-position cock 11911, the movable part 159 of which is so positioned as to effect connection between the second inlet and first outlet ports of the second four-position cock.

If it were desired to bypass the first soot blower and operate only the second soot blower, this could be effected by rotating the movable part 159 of the first fourposition cock through in an anticlockwise sense and moving the movable part of the second four-position cock through 60 in a clockwise sense. In this way the signal from the starter valve 117 conducted through the line 155 would enter the first four-position cock 119a at the first inlet port 163 thereof, flow through the main duct 171 of the movable part 159, leave the first four-position cock by way of the second outlet port 165, enter the first inlet port 163 of the second four-position cock 119b, flow through the movable part 159 thereof first by way of the radial duct 173 and then by way of the main duct 171 to the first outlet port 169 thereof and thence to the signal receiving line 63 of the first control valve 7 associated with the second soot blower. As shown in Fig. 1

seven four-position cocks 119a to 119g are provided to permit sequential operation of a selection of soot blowers chosen from a seriesof seven soot blowers each of which is of the same nature as the soot blower depicted in Figs. 1 to 4 and has associated therewith an air motor and first and second control valves of the kind described with v reference to the valves 7 and 9. Conveniently, the fourposition cocks 119e to 119g are clamped together in a pile 174, adjacent cocks being arranged with'the second outlet port of lone in register with the first inlet port of the other, the neighbouring faces of the adjacent fourposition cocks being formed with registering annular recesses within which are disposed packing rings, such as the ring 175, toV provide an air-tighty joint between the said neighbouring faces.

, The operation of the soot blower shown in Figs. l to 4 l cannow readily be apprehended Upon movingthe knob 133 momentarily to the left so as to open the starter valve 117, a signal air impulse is transmitted from the air supply line 5, through the air-conducting line 147, the starter valve 117, the air-conducting line 155, the first four-position cock 119:1, the signal receiving line 63 and the bore 55 to the first cylinder space 19 of the valve 7. The impulse transmitted to the first cylinder space 19 moves the piston 11 from a first or closed position, namely, that depicted in Fig. l to a second or open position shown in Fig. 2. 1n the second or Open position air fiows from the air supply line 5 by way of the air-conducting line 53, bore 47, port 51, first cylinder space 19, po-rt 71, operates to initiate movement of the spindle 1 to the left, that is to say from its retracted position towards its operative position. As the abutment 79 or" the spindle 1 moves away from the outer end of the rod 85 of the valve 9, that valve opens and air is supplied by way of the air supply line 5, air-conducting line 109, bore 97, port 101, cylinder S3, port 107, bore 193, air-conducting line 111 and orifice 113 to the air motor 3 causing the air motor 3 to speed up and move the spindle 1 to the left at a relatively high speed. The movement of the spindle 1 to the left at the high speed continues until such time as, through contact between the abutment 79 and the outer end of the rod 17, the piston 11 is moved to the left so as to cover the port 71. The' covering of the port '71 cuts oft the air supply by way of the air-conducting line 73 to the air motor and the speed of the air motor since it is now dependent upon the air supply through the line 111 and the orifice 113, is reduced.

As the spindle 1 which is rotating to and fro in an arc continues to advance to the left the piston 11 covers the port 51 so that communication between the first cylinder space 19 and the air supply line 5 is prevented. At this point cleaning fluid is supplied to the blower element associated with the spindle 1. The blowing period continues as the piston 11 advances to the left across the port 51 and terminates a short time after the port S1 is once again uncovered, through the passage to the left of the piston 11. A short time before the nncovering of the port 51, however, the port 71 is uncovered so that some of the air supplied by way of' the air-conducting line 111 and orifice 113 to the air motor 3 is diverted through the air-conducting line 73 and enters the second cylinder space 21 by way of the bore 67 and port 71. The air thus supplied to the second cylinder space 21 serves first to provide a signal impulse in the impulse transmitting line 65 which impulse can be used to operate a subsequent soot blower and, secondly, to accelerate movement of the piston 11 to the left. When in its further motion to the left the piston 11 uncovers the port 51 air fiows from the air supply line 5 by way of the bore 47, port 51, second cylinder space 21, port 71, bore 67 and air-conducting line 73 to the air motor 3, which is once again speeded up. In this way the blowing period is rapidly terminated. At this stage the piston 11 of the valve 7 having passed through a range of intermediate portie-ns such as that shown in Fig. 3 is in its third or open position as illustrated in Fig. 4 and the reversing mechanism between the air motor 3 and the spindle 1 has just initiated movement of the spindle to the right, that is to say towards its retracted position. The supply of cleaning tiuid to the blower element is cut off as movement of the blower element to its retracted position proceeds.

By virtue'of the movement of the piston 11 to the left after uncovering of the port 51 communication between the exhaust port 75 and the first cylinder space 19 by way of the passage between the section 16 of the rod 15 and the bore 25, is effected so that air pressure in the first cylinder space 19 and the signal receiving line 63 is reduced to atmospheric pressure. From the position depicted in Fig. 4 where, as described above, reversal of motion of the spindle 1 has just taken place, since the air is supplied to the motor 3 from the line 73 and the line 111, withdrawal of the spindle to its retracted position takes place at the higher motor speed. As the spindle 1 approaches its retracted position the abutment 77 contacts the end of the rod 15 and returns the piston 11 to the first or closed position shown in Fig. l. As the abutment 77 contacts the rod 15 of the valve 7 and moves the piston 11, the abutment 79 contacts the rod 85 of the valve 9 so that when the spindle 1 reaches its fully retracted position the valve 9 is closed. The supply of air to the motor 3 through the valves 7 and 9 is therefore cut ott and the motor 3 stops, thereby arresting motion of the spindle 1.

It will be appreciated that since, during retraction' of the spindlel, the motor 3 is supplied with working duid through both the valves 7 and 9 maximum power is available to overcome the thrust of cleaning fluid acting on the blower element at the commencement of retraction thereof from operative position.

If desired, instead of the orifice 113 in the air-conducting line 111, there may be provided between the air motor 3 and the air-conducting lines 73 and 111 a throttling valve which is operable to a throttling position either by a cam movable together with the blower element associated with the spindle 1 or by means responsive to the pressure of cleaning fluid discharged past the main valve, the arrangement being such that the throttling action is exerted only or substantially only during a period of discharge of cleaning fluid.

In the system described above, the sequential operation and the speed control are governed by tworobust piston valves and the control means and the control panel or pile 174 are mechanically simple and of compact dimensions.

Referring to Fig. 5, the first, second and fifth soot blowers of a series of seven soot blowers are arranged t0 operate'in sequence the remaining soot blowers being inoperative. It will be seen that the signal receiving lines 63 associated with the soot blowers are respectively connected to first outlet ports 169 of the four-position cocks 1195i and 119g of the pile 174, whilst the signal transmitting lines of the soot blowers except that of the last soot blower of the series are connected each to the second inlet port 167 of the four-position cock following the four-position cock to which the signal receiving lin: 63 of that soot blower is connected. It will be seen that the movable part 159 of each of the four-position cocks 119:1 to 119g occupies o-ne of four useful positions which are positions in which the ducts of the movable part 159 effect connection between the first inlet port 163 and the first outlet port 169 of the cock, the second inlet port 167 and the first outlet port 169 of the cock, the second inlet port 167 and the second outlet port 165 of the cock or the first inlet port 163 and the second outlet port 165 of the cock. When the movable part of a four-position cock is placed in the first of these positions, that is to say the position in which connection is effected between the first inlet port 163 and the first outlet port 169 of a cock, the cock is able to pass a signal impulse to the signal impulse receiving line 63 associated with that cock either from source, that is to say the air supply line 5 by way of the starter valve 117 (see the four-position cock 119a associated with the first soot blower of the series) or, in the case of cocks associated with soot blowers other than the first, from the four-position cock associated with an inoperative soot blower earlier in the series (see the fourposition cock 119e associated with the fifth soot blower of the series). With the movable part of a four-position cock disposed in the second position, that is to say the position in which connection is effected between the second inlet port 167 and the first outlet port 16,9 of the cock, the cock is able to pass a signal impulse from the signal impulse transmitting line of one soot blower to the signal receiving line of the succeeding soot blower (see the four-position cock 119b associated with the second soot blower).v In its third position, that is to say the position in which `,th'eftnovable partV A159 feffects;` con'nection betweenjthe second inletport 167 iand second outlet port 165. of the four-position'cock, a vsignalitnpulse re-v ceived from the signal impulse transmitting line-65 of one soot blower is passed by the four-position cock to which that line is connected to a succeeding four-position cock (see the four-position cock 119C associated with the third soot blower of the series). When in its fourth position, l that is to say the position' in which the movable part 159 effects connection between the first inlet port 163 and the second outlet port 165 of the cock, the four-position cock may bel used to pass a signal impulse from a four-position cock associated with 'a soot blower which is bypassed to a succeeding four-position cock which is associated with an operative or bypassed soot blower. Alternatively, in its fourth positionyo-n the four-position `cock which constitutes the last cock of the pile, is arranged to pass a signal received from a previousfour-position `cock associated with an inoperative soot blower to an exhaustline 176 which includes a throttle `valve 178., The signal irnpulse transmitting line 65 associated withthe nal soot blower of the series also includes a throttle valve-18th If desired, in order to provide a warning at the termination of operation of the operative soot blowers of the series, the

throttle valves

178 and 180 may be in the form of whistles. It will be appreciated that the throttle valve 178 is operative only when the nal soot blower of the series is ino-perative, since when the final soot blower of the series is operative the transmitted signal therefrom is throttled to exhaust through the valve 180. Advantageously, included in an air supply line a which is arranged to supply air to the air supply lines 5 respectively associated with the soot blowers, is a throttle valve 182 by means of which the supply of air to the control valves 7 and 9 of each o-perative soot blower of the series can be controlled thereby adjusting the speeds at which the soot blowers operate. It will be appreciated that the quantity of cleaning fluid discharged during operation of each soot blower is dependent upon the a1r supply to themotor 3 during the blowing period. Accordingly the setting of the valve 182 determines the consumption of cleaning uid by the soot blower during operation. Thus the speed of operation ofeach soot blo-wer can be adjusted by the valve 182 togive optimum consumption of cleaning uid.

The operative signal lines associated with the series of soot blowers illustrated in Fig. 5 are marked with arrows showing the direction of air travel 'n those lines. Thus, upon operation of the starter valve 117 a signal impulse is transmitted through the air-conducting line 155, the first four-position cock 119a to the signal receiving line 63 to the rst soot blower which is then operated. When the first soot blo-wer arrives at the position indicated in Fig. 3, a signal impulse is developed in the signal transmitting line 65 thereof and passed by way of the second four-posltion cock 119b of the pile 174 to the signal impulse receiving line of the sec-nd soot blower ofthe series. The second soot blower is then operated and as it traverses the position shown in Fig. 3 a signal impulse is passed thro-ugh the signal transmitting line 65 of that soot blower to the th rd fourposition cock 119C of the pile 174. This signal then traverses the four-position cocks 119C and 119d of the pile 174 and passes through the fifth cock 119e in the pile and out to the signal impulse receiving line 63 of the fth soot blower which is associate-d with that cock. The fifth soot blower is then operated and as it passes through the position shown in Fig. 3, it transmits a s gnal impule through its signal impulse transmi.ting line 65 to the sixth four-po-siton ccck 119i of the pile. The signal received at the sixth four-position cock of the pile passes through that cock, the succeeding cock 119g, the exhaust line 176 and the throttle valve 178 to atmo-sphere. A disposition of the movable parts 159 of the four-position cocks of the pile 174 is shown in Fig.

soot blowers of an associated series of seven soot blowers are ren-dered sequentially operative, whilst the remaining soot blowers of the series are inoperative. It will be appreciated that since the seventh soot blower of the series is arranged to be operative the signal impuise transmitted by that soot blower as it traverses the position shown in Fig. 3 will be exhausted through a throttle valve, such as the valve shown in Fig. 5, to atmosphere.

Where several soot blowers are operated in sequence in the manner described above, the total cleaning time is reduced not only because the advance of the blower element to operative position and retraction of the blower element to its retracted position are relatively rapid but also because very shortly after the blower element ceases to discharge a succeeding blower element commences its period of discharge.

What is claimed is:

1. A fluid heater cleaner having a blower element arranged to be power operated and to be projected for operation from an inoperative or retracted posiion and to be rotated while in operative position, rotary driving means arranged through unidirectional rotation to effect projection, retraction and rotation of the blower element and means responsive to the blower element travel to effect rotation of the driving means at a higher speed during projection of the blower element to and retraction of the blower element from operative posit'cn than during a blowing period when the blower element is in operative position.

2. A fluid heater cleaner having a blower element arranged to be projected for operation from an inoperative or retracted position to an operative position and to be rotated while in said operative position, rotary driving means arranged through unidirectional rotation to effect projection, retraction and rotation of the blower element, a uid pressure motor adapted, when ccnnect d to a source of work'ng uid, to actuate the driving means, and first and second control valves in parallel feed relatisnship to said motor and responsive to the travel of said blower element, the first control valve being adapted to effect connection between the motor and a source of wo-rking Huid during projection of the blower element t-o and retraction of the blower element from' operative position, the second control valve being adapted to effect connection between the motor and the source of working duid through a restrictor when the blower elemmt is in operative position and during projection of the blower element to and retraction of the blower element from operative position.

3. A uid heater cleaner as claimed in claim 1, wherein a fluid pressure motor is arranged to operate the blo-wer element through the rotary driving means and means are provided responsive tothe blo-wer element travel for supplying working uid to the motor at a higher rate during said projection and retraction of the blower element than during said blowing period when the blower element is in operative position.

4. A fluid heater cleaner as claimed in yclaim 3, wherein said working fluid supply means include first and second control valves arranged to govern the flow of working uid to the motor, the first control valve serving, through mo-vement o-f a movable valve member thereof in dependence upon axial positioning of the blower element, to effect a reduction in the rate of ow of working fluid to the motor during said blowing period when the blower element is in operative position, and the second control Valve having a movable valve member which is movable to a closed position through movement of the blower element to the retracted position.

5. A tiuid heater cleaner as claimed in claim 4, wherein said first control valve is arranged to ccnnect a source of working fluid to the motor during projection to operative position and retraction of the blower element 1l and said second control valve is `arranged to connect the source to the motor through a restrictor when the blower element is in operative positicn and during profecti n to operative position and iretraction of the blower element.

6. A fluid heater cleaner as claimed in claim 5, wherein the first control valve includes means respansve to the travel of said blower element to effect transmision of a control impulse when said blower element reaches a predetermined position, which impulse may be utilized to in'tiate operatio-n of another fluid heater cleaner.

7. A uid heater cleaner as claimed in claim 6, wherein the first control valve includes means to open a port to effect transmission of the control impulse shortly before the blower element reaches its fully retracted position.

8. A fluid heater'cleaner as claimed in claim 5 including first and second abutments movable with said blower element and aligned with respective cnes of sald movable valve members, and where'n said movable valve member of the second control valveV is movable to a closed position through movement of the blower element to the retracted position, and said movable valve member of the first control valve is movable from a first, closed position to a second, open posiifn by the application of a control impulse, said movable valve member of said first control valve also being movable through `a range of closed posit'ons while the blower element is in operative position, to a third, open positicn by the action of said first abutment, and being further movable, through movement of the blower element to the retracted position, from the third position to the first position by the action of said second abutment.

9. A uid heater cleaner as claimed in claim 8, wherein the first control valve is a piston valve including a first port connected to a source of working uid and the piston of which, when in the first position, occupizs an intermediate position in the cylinder with first and second cylinder spaces on opposite sides thereof, and masks said first port to block the inlet of working fluid, said piston being movable in each direction past said first port, said first control valve also including an init port'on communicating with said first cylinder space for the passage of uid for moving said piston to the second 12 position, an outlet port communicating with the second cylinder space for the transmisin of a control impulse which may be used for initiating operaton of another uid heater cleaner, and a third port connected to said motor and arranged to be masked by the piston durng a blowing period while the blower element is in operative position, an exhaust port associated with the first cylinder space, and an obturator arranged to open said exhaust port towards the end of the movement of said lpiston to the third position.

10.A fluid heater cleaner as claimed in claim 9, wherein the effective piston area exposed to the first cy.ind2r space is greater than the effective piston area exposed to the second cylinder space.

11. A fluid heater cleaner as claimed in claim 10 wherein said piston cf the first control valve is spring biased towards the third position.

12. A fluid heater cleaner as claimed in cla'm l0, wherein the piston is formed with rods extending in opposite directions and having end portions extending through the end walls of the cylinder, and the end portlon of the rod associated with the first cylinder space is of smaller diameter than the end portion of the rod associated with the second cylinder space.

13. A fluid heater cleaner as claimed in claim 12, wherein the rod associated with the first cylinder space is formed with an outer end part of increased diameter arranged to slide through the bore in a cylinder end and to act as the obturator.

14. A uid heater cleaner as claimed in claim 12 wherein the rod associated with the second cylinder space is formed with an inner end part of increased diameter alford'ng a shoulder arranged to act as a stop for engagement with the cylinder end through which the rod extends.

References Cited in the file of this patent UNITED STATES PATENTS 2,491,838 Thomas Dec. 20, 1949 2,722,033 Glinn et al. Nov. 1, 1955 2,730,749 Hibneret al Jan. 17, 1956 FOREGN PATENTS 669,387 Great Britain Apr. 2, 1952 UNITED STATES PATENT OEEICE CERTIFICATE 0F CORRECTION Patent No, 2,865,042 December 23, 195e William McColl It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 8, line 40, for "ll9a and 119g" read e@ 119e to 119g mi@ Signed and sealed this 31st day of March 395% (SEAL) Attest:

KARL H. AXLINE ROBERT C. WATSON Commissioner of Patents Attesting Officer