CA2117510C - Closed loop sludge flow control system - Google Patents
Closed loop sludge flow control system Download PDFInfo
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- CA2117510C CA2117510C CA 2117510 CA2117510A CA2117510C CA 2117510 C CA2117510 C CA 2117510C CA 2117510 CA2117510 CA 2117510 CA 2117510 A CA2117510 A CA 2117510A CA 2117510 C CA2117510 C CA 2117510C
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- sludge material
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- positive displacement
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Abstract
A system and method for controlling operation of a sludge material handling system is disclosed. The sludge material handling system includes a positive displacement piston/cylinder pump (10), a sludge material feed system which delivers sludge material to the pump (10), and a sludge material disposal system (160) which receives and disposes of sludge material from the pump (10). A first parameter is sensed, the first parameter bearing a known relationship to an actual volume of sludge material delivered during a pumping cycle. An output value is determined from the first parameter. A control signal is provided as a function of the output value.
Description
CLOSED LOOP SLUDGE FLOW CONTROL SYSTEM
BACE~GROUND OF TH~ INVT'~TION
The present invention relates to systems for disposing of sludge material. In particular, the present invention relates to a sludge material 5 handling system in which a positive ~ pump, a sludge material feed system which delivers sludge to the positive ~' ' pump and a sludge material disposal system which receives and disposes of sludge from the positive ~"e~'- pump can be controlled as a function of an ach~al volume of sludge delivered by the pump during one or more pumping cycles.
In recent years, sludge pumps have found increasing use for conveying sludge through pipelines in municipal and industrial ,~l ' Positive ~' ' sludge pumps offer a number of significant - " ~
over screw or belt conveyers. For example, a positive '~i~rl~ ' sludge pump can pump sludge through a pipeline while containing odors in order 15 to maintain a safe and secure working ~ Positive ~"er'- -pumps are capable of pumping dlicl~, heavy sludge materials which may not be practical for belt or screw conveyers. This is y~ i ~ ~ important where the sludge material needs to be dried and burned in an ~
Pump and pipeline systems aLso take up less space than screw~0 or belt conveyers and, with the use of simple elbow pipes, are capable of , ii..b sludge materials around corners. ~ y, positive ~ er'- sludge pumps offer a reduction in noise over conveyers as well as greater c' ' and reduced spillage.
Various state and federal l~ v ' covering the processing 25 and disposal of sludge require that the processor accurately measure and record the amount of material handled. Positive ~ sludge pumps such as those described in Oaldey et al., U.S. Patent No. 5,106,272, entitled "SLUDGE FLOW MEASURING SYSTEM", can accurately measure the volume of sludge ~ d. Oaldey et al., discloses a system for ~ A ~ i 1 7 ~ 1 0 i ~ high solids sludge which includes a positive d'sr'- pump for pumping sludge through a pipeline. The volume of sludge i . t~ d is accurately measured by d ~ the fill ~.. of the pumping cylinder during each pumping cycle. The fill pc.~ ~ is d~; ~ by S using any of a nurnber of se~d I including material flow signals, measured time intervals, hydraulic fluid pressure, and hydraulic fluid flow rate during each pumping cycle.
One X of the system and pump disclosed in Oakley et aL, includes a valve, commonly referred to as a poppet valve, between the pumping cylinder and the outlet which opens and connects the pumping cylinder to the outlet only when the pressure within the pumping cylinder essentially equals the pressure at the outlet. The timing of the opening of the outlet poppet valve during the outlet stro}e provides a means for d~; 1" the fill ~. or the total volume delivered during each pumping stro}e.
A second e ~ " of the system and pump disclosed in Oakley et al. includes and outlet valve, commonly referred to as a pivoting transfer tube valve, which connects the oudet to the pumping cylinder during the entire pumping stroke. In this ~ ~ ~ " t, both the hydraulic pressure driving the piston and the outlet pressure are sensed during the pumpirlg stroke. D~ , either the time or the piston position during each pumping stroke when the hydraulic pressure equals the outlet pressure can be used to derive a fill p~ or volume delivered during each of the pumping strokes.
In a typical sludge material handling systern, a sludge material feed system delivers sludge to the positive ~"sr'~ pump. The sludge material feed system may include a belt press, an auger, a centrifuge or other devices for drying the sludge and/or delivering it to the positive d'~rl - ' pump.
CA2i 1 7510 The sludge material handling system also typically includes a sludge material disposal system which disposes of sludge pumped by the positive di~r ~ ~ pump. Typically, the sludge material disposal system will include an which the sludge. However, the S sludge material disposal system could include other means of disposing of the sludge material in a~,-' with El....~ ' Protection Agency (EPA) .~ ' For example, the sludge material disposal system could include a truck which transports the sludge to a remote area where it is spread out over the ground.
In any case, EPA ~cig ' frequently require accurate and recordirg of the amount of sludge which is being disposed.
In most instances, a sludge material handling sy.stem requires at least three or four " ' '- to monitor and control the sludge material feed system, the positive :" .' pump and the sludge rnaterial disposal system.
15 r .~, " a number of ". ' '~ to monitor and control the sludge material handling system adds significant cost to the disposal of sludge.
'" "~, pre,sent systems leave room for human error and makes it difficult to keep accurate records of the amount of sludge handled by the system. Keeping accurate records is typically necessary to satisfy EPA
SUluM~RY OF THF TNVFl~TION
The present invention is based upon the l. " that a sludge material handling system with a positive ~!5pl_ ' piston/cylinder pump, together with a system which d: the percent fill of the pump 25 qlinder(s) or actual volume of sludge delivered during a pumping qcle, offers the capability of ~ " _ the pump, 'l~
~ " _ a sludge material feed system which delivers sludge to the pump and "y . ~ " ~ a sludge material disposal system which receives and disposes of sludge from the pump.
CA21 i7~10 It is not normally possible to fill the glinder(s) of a positive :' ,' pump to 100~o of the }nown capacity. The sludge being pumped typically contains air and other . ~ materials. Therefore, a portion of each pumping stroke of the positive ~ ' pump involves 5 simply; , ~ ~ ,, the sludge in the grlinder before the pressurc driving the piston u. . the pressure at the outlet of the pump so that the sludge begins to flow out of the cylinder. In the present invention, at least one parameter related to operation of the positive ~' ,1; pump is sensed in order to identify the point during the pumping strolce when the hydraulic 10 pressure applied to the piston is sufficient to overcome the outlet pressure (so that sludge material begins to be pumped out of the glinder). From that ~ r '- , which bears a known L_~ ' ', to an actual volume of sludge delivered during a pumping gcle, the pump as well as upstream and down stream c . of the sludge material handling system may be The sludge material handling system of the present invention includes a positive ~ piston/glinder pump for pumping sludge through a pump outlet during each pumping stro~e. A sludge material feed system delivers sludge to a positive ~!q~_ ' pump inlet. The positive 20 ~I~sF~- pump delivers sludge through the pump outlet to a sludge material disposal system. A parameter is sensed during each pumping stroke, the parameter being related to operation of the pump and having a known ,.' ' to an actual volume of sludge delivered during the pumping stroke. An output value is ~' ' from the parameter sensed.
25 A control signal is provided as a function of the output value.
BP~TFF DFSC}~PI-ION OF T~TF. DRAWINGS
Figure 1 is a p.,~l~e.livc view, with portions bro~en away, of a sludge pump system which uses inlet and outlet poppet valves.
~ ~. 2 ~ ~ ~ J l 1~
S
Figure 2 is a bloc} diagram of a ~ system for d - and r ' ' volumes of sludge materials pumped by a positive :" . ' pump.
Figure 3 is a block diagram of a control system for ~h~ ' ,, S a sludge material handling system.
Figure 4 is a nOw chart which illustrates onc method of . " ~ material handling system 150 in the manner described above.
DpTAn Fn DF-ct~RnrFToN OF l~F pplP.FP.T~2Pn Fr~RoDTr~F~lTs A. OV~.T~VIP.W OF PUr 'P 10 Figure 1 shows a two qlinder h, ' '1~ driven positive d sl"- sludge pump 10 which could be used with the present invention. It should be noted, however, that other sludge pumps with variations in the _ q, of the hydraulic and control valve could bc used as well. Pump 10 includes inlets 12 and 14, outlet 16, material qlindcrs 18 and 20, material pistons 22 and 24, inlet poppet ~alves 26 and 28, outlet poppet valves 30 and 32, hydraulic inlet valve glinders 34 and 36, hydraulic outlet valve cylinders 38 and 40, poppet valve housing 42, hydraulic drive pistons 44 and 46, hydraulic glinders 48 and 50, hydraulic pump 52, high pressure lines 54, control valve assembly 56, hydraulic reservoir 58,1ow pressure line 60, folward and rear switching valves 62 and 64 and - 66.
High solids sludge material (sludge) is received at inlets 12 and 14, and is pumped through outlet 16, typically to a pipeline (not shown).
Material pistons 22 and 24 ,c.;~.~t. in material glinders 18 and 20. Inlet poppet valve 26 controls the ~ow of sludge from inlet 12 to material cylinder 18. Similarly, inlet poppet valve 28 controls the flow of sludge from inlet 14 to material glinder 20. The flow of sludge from glinders 18 and 20 to outlet 16 is controlled by outlet poppet valves 30 and 32, leD~ti.~
CA2i l 7~ 1 0 Inlet poppet valves 26 and 28 are controlled by hydraulic ir~et valve cylinders 34 and 36~ L._I~. Outlet poppet valves 30 and 32 are controlled by hydraulic outlet valve cylinders 38 and 40.
In the particular position shown in Figure 1, inlet poppet valve 5 26 and outlet poppet valve 32 are in an open position. This means that piston 22 is moving away from poppet valve housing 42, while piston 24 is moving toward poppet valve housing 42. Sludge is being drawn through inlet 12 and into cylinder 18, while sludge is being pumped from cylinder 20 to outlet 16.
Material pistons 22 and 24 are coupled to hydraulic drive pistons 44 and 46, l~L._I~, which move in hydraulic cylinders 48 and 50.
Hydraulic fluid is pumped from hydraulic pump 52 through high pressure lines 54 to control valve assembly 56. Although not shown in Figure 1, hydraulic pump 52 may be driven by an input shaft connected to a separate motor. Assernbly 56 includes throttle and checlc valves which control the 5 , ~ _ of high and low pressure hydraulic fluid to hydraulic qlinders 48 and 50 and to poppet valve cylinders 34, 36, 38 and 40. Low pressure hydraulic fluid returns to hydraulic reservoir 58 through low pressure line 60 from valve assembly 56.
Forward and rear switching valves 62 and 64 sense the position of piston 46 at the forward and rear ends of travel and are ~
to control valve assembly 56. Each time piston 46 reaches the forward or rear end of its travel in cylinder 50, a valve sequence is initiated which results in the closing of all four poppet valves and a reversal of the high pressure and low pressure - to cylinders 48 and 50.
The sequence of operations of pump 10 is generally as follows.
As drive pistons 44 and 46 and their connected material pistons 22 and 24 come to the end of their stroke, one of the material cylinders (in Figure 1, cylinder 20) is d~ material to outlet 16, while the other cylinder 18 - CA21:1 7~
is loading material from inlet 12. At the end of the pumping stroke, rnaterial piston 24 is at its closest point to poppet valve housing 42, while piston 22 is at its position furthest from poppet valve housing 42. At this point, switching valve 62 senses that hydraulic drive piston 46 has reached 5 the forward end of its stroke. Valve assembly 56 is activated which causes poppet valve cylinders 34 and 40 to be actuated. This causes inlet poppet valve 26 and outlet poppet valve 32 to close.
At this point, pistons 22 and 24 are at thc ends of their stroke, and their direction of movement is about to reverse. AU four poppet valves 26, 28, 30 and 32 are closed. Hydraulic pressure begins to increase in cylinder 48, which drives piston 44 forward. In t~n, piston 22 moves forward toward poppet valve housing 42. Piston 22, therefore, is now in a pumping or ~.' ' v ~ stroke. At the same time, hydraulic fluid located forward of piston 44 is being i ~ ~ d from qlinder 48 through 15 ~ . 66 to the forward end of cylinder 50. This applies hydraulic pressure to piston 46 to move it in a rearward direction. As a result, material piston 24 begins moving away from poppet valve housing 42 and it is in a loading or filling stoke. When the pressure in vah~e housing 42 below poppet vah~e 28 essentially equals the pressurc on the inlet side, poppet 20 valve 28 opens, which aUows sludge to flow through irllet 14 and into qlinder 20 during the fiUing stroke.
As piston 22 be~vins to move forward, it first . , ~ s the sludge within cylinder 18. At the moment when the . . - ~ sludge equals the pressure of the . . ~ d sludge in outlet 16, poppet valve 30 25 opens. Since the poppet valve for the d:~h~, cylinder opens only when the pressure of the content of a cylinder essentiaUy equals the pressure in the pipeline, no material can flow back.
The operation continues, with piston 22 moving for vard and piston 24 moving rearward until the pistons reach the end of their respective ~2 1 1 7~5 1 0 strokes. At that point, switching valve 64 causes valve assembly 56 to close all four poppet valves and reverse the . ~ of the high and low pressure fluids to qlinders 48 and 50. The operation continues with one material piston 22 or 24 operating in a filling stroke while the other is S operating in a pumping or discharge stroke.
It should be noted that pump 10 is one of several positive ILr pump ~ 5" which could be used with the present invention. For example, pump 10 could be of the type which uses a pivoting transfer tube valve, instead of poppet valves, to cormect the pumping 10 cylinder to the outlet during the entire pumping stroke. Detailed d - -of several positive :" ' pumps which could be used with the present invention may be found in Oakley et al., U.S. Patent No. 5,106,272, which is ' hereirl by reference.
B. MONITOP'T~G SYSTFr' 100 Figure 2 shows one possible e ~ ~- of a ~, system which mouitors the operation of pump 10 to provide accurate of the volume of sludge pumped on a . ~..le h, ~, _' - basis and on an ~s ' ~ basis. Monitor system 100 includes pump 10, computer 102, which in a preferred ' is a ~ based computer 20 including associated memory and associated input/output circuitry, clock 104,output device 106, input devioe 108, poppet valve se~rs 110, hydraulic flow rate se~rs 112, and hydraulic system se~rs 114.
Clock 104 provides a time base for computer 102. Although shown separately in Figure 2, clock 104 may be contained as part of 25 computer 102.
Output device 106 is preferably any of a number of devices.
For example output device 106 can include a display output such as a cathode ray tube or a liquid crystal display. Output device 106 can also be a printer, or a ~ device such as a cellular phone which CA2 i 1 7~ ~ ~
g transmits the output of computer 102 to another computer based system (which may monitor or control the overaD operation in which pump 10 is being used).
Input device 108 can also take a variety of forms. In one 5 preferred ~ ~' input device 108 is a ke~pad entry device. Input device 108 can also be a keyboard, a remote program device or any other suitable ' ~ for providing ~ r '- to computer 102.
Sensors 110, 112 and 114 monitor the operation of pump 10 and provide signals to computer 102. The l sensed by sensors 110, 10112 and 114 provide an indication of the percent fill of the pumping cylinder during each pumping stroke of pump 10, and allow computer 102 to determine the time period of each cycle. From this ' computer 102 .' ~ the volu ne of material pumped during that particular cycle, the r ' ' ~ volume pumped during a number of pumping cycles, the 15~ pumping rate and/or an average pumping rate over a selected period of time. Computer 102 stores the data in memory, and also provides signals to output device 106 based upon the particular ~ r - selected by input device 108.
In one preferred . ~ ' ~ the d~,i ~ of volume 20 pumped during a pumping cycle is as follows. Hydraulic system sensors 114 provide signals to computer 102 indicating the start time and stop time of each pumping stroke in pump 10. These signals are supplied to computer 102 by sensors 114 preferably in the form of interrupt signals.
Poppet valve sensors 110 sense when the outlet poppet valve 25 opens during the pumping stroke. The signal from poppet valve sensors 110 are also preferably in the form of an interrupt signal to computer 102.
Hydraulic flow rate sensors 112 are preferably located near hydraulic pump 52 and sense the flow rate of hydraulic fluid from pump 52.
Serlsors 112 are used to provide an indication to computer 102 that the - C-A 2 ~1 17~
velocity of pistons 22 and 24 has remained essentially constant during each pumping cycle. Signals from sensors 112 are preferably in the form of digitally converted analog signals to computer 102. In other preferred ' - ' if piston velocity is not intended to remain constant, sensors 112 are used to adjust the calculated volume of sludge purnped during each pumping stroke.
As pistons 22 and 24 travel through cylinders 18 and 20 during their respective pumping strokes, sludge in the qlinders is _ , ' When the sludge in a glinder is near fully . . i the pressure in that cylinder increases as piston 22 or 24 continues to move forvard in its pumping stroke. The time, during each pumping stroke, that an outlet poppet valve opens is ,.~ of the time that the piston (22 or 24) has built up sufficient pressure to push sludge out of the cylinder, through outlet 16, to a pipeline.
Computer 102, which receives signals from hydraulic systems sensors 114 indicating the start and stop times of each pumping strolce, and poppet valve sensors 110 indicating that sludge is being pumped out of the cylinder, ~ ~ a fill p~ by dividing the pumping stroke time after the poppet valve opens by the total pumping stroke time.
If hydraulic flow rate sensors 112 provide computer 102 with ~ ~ indicating that piston velocity did not remain essentially constant, r ~ are made to the calculated fill ~l. because this method of ~ fill pe.~ ~ is actually based upon the ratio of the length of the piston stroke after the poppet valve opens to the total stroke length.
Knowing the total ' l ' volume of the cylinder and the calculated pc,~ ~ fill during each pumping stroke, computer 102 calculates the actual volume pumped during each cycle. That value may be stored in a register within the memory of computer 102 and/or supplied to C ~ 2 ~
another computer which monitors system 100 and pump 10. In addition, computer 102 updates a register which keeps an r ' ' ~ total volume pumped.
Because computer 102 may also determine the length of time S during each qcle and the ~ time during which an r ' ' ~ li volume has been pumped, it is possible to calculate an pumping rate for each qcle, as well as an average pumping rate over the ~ time. All four values (volume pumped in a particular cycle, total - ' ~ volume, ~ pumping rate, and averagc pumping rate) can be calculated by computer 102.
It should be noted that monitor system 100 is one of many ~ v system . 5,, ~ which could be used to calculate a percent fill, or an actual volume of sludge pumped, during each pumping stroke. For example, ~nitor system 100 could include piston position sensors, instead lS of hydraulic system sensors 114, to notify computer lû2 of the start and stop times of each pumping stroke. Also, different ~ systems may be neoessary for different positive ~ pump . 5" Any ~ ~ system capable of ' ' . the peroent fill of each pumping stroke of a positive d srl- piston/qlinder pump could be for system 100 and used with the present invention.
C. ~T I JDG~ MATF.R-A- . HA~T .~G SYSTI~r ' 1~0 Figure 3 shows a preferred; ' - ' of sludge material handling system lS0 of the present invention. System lS0 includes monitor system 100 (including pump 10), computer 152, clock 154, output device 156, input devioe 158, sludge material feed system 160 and sludge material disposal system 162. In a preferred . ' ' t, computer 152 is a ~ u~J~u~r-based computer including associated memory and associated input/output circuitry. Clock 154 provides a time base for computer 152.
Although shown separately in Figure 3, clock 154 may be contained as part of computer 152. Output device 156 can include a display output such as a cathode ray tube or a liquid crystal display. Output device 156 can also be a printer, or a; ~ device sucb as a cellular phone which trar~nits the output of computer 152 to another computer based system.
5 Input device 158 can also take a variety of forms. In one preferred ~ ' input device 158 is a keypad entry device. Input device 158 can also be a keyboard, a remote program device or any other suitable - ' ~ for providirg ~ ~ to computer 152.
Although in Figure 3 computer 152, clock 154, output device 156 and input device 158 are shown separate from computer 102, clock 104, output device 106 and input device 108 of monitor system 100, in other preferred; ~ ' system 100 and system 150 are integrated and share these ~ , Sludge material feed system 160 can be any of a number of devices capable of drying sludge and/or supplying sludge to pump 10. For ex~nple, feed system 160 can be a oentrifuge which is used to dly sludge and supply it to pump 10 for pumping to sludge material disposal system 162.
Feed system 160 can also be a belt conveyer or a screw-type feeder. Feed system 160 can even include manual dumping, by a hurnan operator, of sludge into a hopper or intake area of purnp 10.
Sludge material disposal system 162 can be any device which disposes of sludge delivered by pump 10. In many instances, the disposal of sludge with disposal system 162 is regulated by the EPA. I~pically, disposal system 162 is an ~ ~ which ~ ~ the sludge delivered by pump 10 in acwl~ with EPA .~i" ' However, disposal system 162 can also be a truck which is loaded with sludge from pump 10 and which transports the sludge to another location for disposaL
D. DEl~.T~MINATION OF W~.TGHT OF SLUDGL
MAI~RTAT puMpT~n 7~J~ 0 EPA ,~,, ' often allow tbe disposal of only oertain quantities of sludge. These quantities may be based on volume, but instead, are frequently based on weight. System 150 can be used to determine the weight of sludge pumped during a single pumping cycle and an ?
5 weight pumped over a number of pumping cycles.
Typically, a user of system 150 }nows the weight per .' r unit of the particular sludge material being pumped. This is supplied to computer 152 through input devioe 158. Through output devioe 106, system 100 provides computer 152 with ~ r .~
0 IG~ of the volume of sludge pumped during a single purnping cycle, the ? ~ ' d volume pumped over a number of pumping cycles, the ~ ~' ~ pumping rate and the average ~ ' -pumping rate. Computer 152 d~; from this ' and from the weight per ~ unit, the weight of sludge pumped during a single 15 pumping cycle, the r ' ' weight pumped over a number of pumping cycles, the weight pumping rate, and the average weight pumping rate.
Clock 154 provides computer 152 with r " indicating the dates and times that the sludge is pumped. This r " is useful 20 in providing date stamped readouS, for the EPA, which verify dates and times of the disposal of quantities (by volume or weight) of sludge.
Computer 152 stores the above r " in memoq and provides signals to output device 156 based upon a particular r .~
format selected by input de~lioe 158. The date stamped r " ~ may be 25 recorded on a chart recorder, printed out in a report format or stored in a database for future use.
E. CONTROL OF PUMP 10. pFFn SYSTF.M 160 ANl~
DT~PO~L SYSTEM 162 CA2 1 i 751:3 Because handUng system 150, with the help of monitor system 100, can determine actual quantities (volume or weight) of sludge pumped by pump 10, system 150 can more easily control the 1~ Of sludge.
Based upon the percent fill of each qlinder as d~ ~ ' by monitor S system 100, computer 152 of handUng system 150 controls the operation ofany or all of pump 10, feed system 160 and disposal system 162. Control of feed system 160 can include; ~" the starting, the stopping and the rate of feed ~r Control of pump 10 can include . ~ starting and stopping of the pump. It can also include ~ ' the pump speed.
Control of disposal system 162 varies greatly depending on the particular type of disposal system used. For cxample, if system 162 includes an ~ , computer 152 can control the operating i . c, the amount of fuel used to incinerab the sludge, and other operating l of the .
In one preferred: ~ of the present invention, a user of material handling system 150 inputs, through input device 158, a maximum quantity of sludge to be processed by system 150. As discussed above, computer 152 d from the measured, ~ ' volume of sludge pumped by pump 10 and from the weight per ~ unit of the sludge, an r ' ~ weight of sludge pumped by pump 10 after each pumping stroke. When the - ~ ~ weight of sludge processed by system 150 equals the maximum quantity of sludge to be processed, computer 152 generates a control signal to control one or more of pump 10, feed system 160 and disposal system 162.
For example, the control signal can cause feed system 160 to stop delivering sludge to pump 10. In this case, computer 152 may also generate additional control signals to control pump 10 and/or disposal system 162. The addUtional control signals can be used to cause pump 10 to stop pumping and disposal system 162 to stop operating as well. However, in alternate ' ' one or both of pump 10 and disposal system 162 is allowed to continue operating after feed system 160 is stopped in order to clean out sludge remaining in the system.
While in preferred ~ ' ~ " ~ control signals are generated S to control pump 10, feed system 160 and disposal system 162, it sbould oe noted that any one of pump 10, system 160 and system 162 can be controlled alone by system 150.
For example, in one preferred ~ - of the present inventio4 a user inputs through input device 158 a desired rate at which pump 10 is to pump sludge to disposal system 162. Monitor system 100 provides computer 152 with the percent fill during each pumping stroke.
Based upon the percent fill during each pumping stroke or over a number of pumping strokes, computer 152 generates control signals which control the rate of which feed system 160 supplies sludge to pump 10. If the peroent fill is too low for pump 10 to pump sludge at the desired rate, the rate at which feed system 160 supplies sludge to pump 10 is increased. Iikewise, if the peroent fill is too high for pump 10 to pump sludge at the desired rate, the rate at which feed system 160 supplies sludge to pump 10 is decreased. This method of ~ " ~ matedal handling system 150 is illustrated in the flow chart shown in Figure 5.
In another preferred e ' ' t, disposal system 162 includes an ~ ~ which requires a known quantity of fuel to incinerate a given quantity of sludge. This ~ ' - is supplied to computer 152 by input device 158. Monitor system 100 provides computer 152 with the percent fill dudng each pumping stroke. Based upon the percent fill dudng each pumping stroke and over a number of pumping strokes, computer 152 generates control signals which control the rate and/or total quantity of fuel used by disposal system 162 while ~ ~ _ the sludge. One method of C A ~ 51 0 ~ ' g material handling system 150 in a~,, ~ with this preferred ~ is illustrated in the flow chart shown in Figures 6A and 6B.
In another preferred ~ " of the present invention, disposal system 162 also includes an ~ However, in this 5 ~ ~ - - t, there is a known ~ ~ . between the quantity of sludge material supplied to the and the i , c at which the - operates. This ~ is supplied to computer 152 through input device 158. An operator of system lS0 inputs, through input device 158, a desired i . c and the weight of the sludge per 10 ~ unit. Based upon the known ,~ ~ ~ . between the quantity of sludge material ~ and the l , c, computer 152 generates control signals which control one or both of feed system 160 and pump 10 so that a sufficient quantity of sludge is supplied to disposal system 162 to maintain the desired i . c.
In other preferred e ~ " control signals generated by computer 152 need not be based only on sensed r ' relating to an a~ual volume of sludge delivered during each pumping cycle. Computer 152 can also sense p related to the operation of feed system 160 and/or disposal system 162 and generate control signals based upon the 20 . ' of the actual volume of sludge deUvered during each pumping cycle and these p For example, in yet another preferred ~ _~ of the present invention which includes an in disposal system 162, computer 152 senses the operating t. ~l-- A~' -- C, compares it to a desired operating ~- c and ~: a difference between the sensed i . c and the desired .~
c. Next, computer 152 ~how much more or less sludge should be suppUed to disposal system 162 to obtain and maintain the desired A~ C. Based upon the quantity of sludge being delivered C-A2i ~7-51~
with each stroke of pump 10, computer 152 generates control signals which cause feed system 160 and pump 10 to increase or decreasc the rate at which sludge is delivered to disposal system 162. Two methods of ~ " ~ operation of material handling system 150 as a function of both S an aclual volume of sludge delivered and a parameter related to operation of sludge material feed system 160 or sludge material disposal system 162 are shown in the flow charts of Figures 7 and 8.
Although the present invention bas been described with reference to preferred: ~ " workers skilled in the art will recogr~ize 10 that changes may be made in form and detail without depar~ng from the spirit and scope of the invention.
BACE~GROUND OF TH~ INVT'~TION
The present invention relates to systems for disposing of sludge material. In particular, the present invention relates to a sludge material 5 handling system in which a positive ~ pump, a sludge material feed system which delivers sludge to the positive ~' ' pump and a sludge material disposal system which receives and disposes of sludge from the positive ~"e~'- pump can be controlled as a function of an ach~al volume of sludge delivered by the pump during one or more pumping cycles.
In recent years, sludge pumps have found increasing use for conveying sludge through pipelines in municipal and industrial ,~l ' Positive ~' ' sludge pumps offer a number of significant - " ~
over screw or belt conveyers. For example, a positive '~i~rl~ ' sludge pump can pump sludge through a pipeline while containing odors in order 15 to maintain a safe and secure working ~ Positive ~"er'- -pumps are capable of pumping dlicl~, heavy sludge materials which may not be practical for belt or screw conveyers. This is y~ i ~ ~ important where the sludge material needs to be dried and burned in an ~
Pump and pipeline systems aLso take up less space than screw~0 or belt conveyers and, with the use of simple elbow pipes, are capable of , ii..b sludge materials around corners. ~ y, positive ~ er'- sludge pumps offer a reduction in noise over conveyers as well as greater c' ' and reduced spillage.
Various state and federal l~ v ' covering the processing 25 and disposal of sludge require that the processor accurately measure and record the amount of material handled. Positive ~ sludge pumps such as those described in Oaldey et al., U.S. Patent No. 5,106,272, entitled "SLUDGE FLOW MEASURING SYSTEM", can accurately measure the volume of sludge ~ d. Oaldey et al., discloses a system for ~ A ~ i 1 7 ~ 1 0 i ~ high solids sludge which includes a positive d'sr'- pump for pumping sludge through a pipeline. The volume of sludge i . t~ d is accurately measured by d ~ the fill ~.. of the pumping cylinder during each pumping cycle. The fill pc.~ ~ is d~; ~ by S using any of a nurnber of se~d I including material flow signals, measured time intervals, hydraulic fluid pressure, and hydraulic fluid flow rate during each pumping cycle.
One X of the system and pump disclosed in Oakley et aL, includes a valve, commonly referred to as a poppet valve, between the pumping cylinder and the outlet which opens and connects the pumping cylinder to the outlet only when the pressure within the pumping cylinder essentially equals the pressure at the outlet. The timing of the opening of the outlet poppet valve during the outlet stro}e provides a means for d~; 1" the fill ~. or the total volume delivered during each pumping stro}e.
A second e ~ " of the system and pump disclosed in Oakley et al. includes and outlet valve, commonly referred to as a pivoting transfer tube valve, which connects the oudet to the pumping cylinder during the entire pumping stroke. In this ~ ~ ~ " t, both the hydraulic pressure driving the piston and the outlet pressure are sensed during the pumpirlg stroke. D~ , either the time or the piston position during each pumping stroke when the hydraulic pressure equals the outlet pressure can be used to derive a fill p~ or volume delivered during each of the pumping strokes.
In a typical sludge material handling systern, a sludge material feed system delivers sludge to the positive ~"sr'~ pump. The sludge material feed system may include a belt press, an auger, a centrifuge or other devices for drying the sludge and/or delivering it to the positive d'~rl - ' pump.
CA2i 1 7510 The sludge material handling system also typically includes a sludge material disposal system which disposes of sludge pumped by the positive di~r ~ ~ pump. Typically, the sludge material disposal system will include an which the sludge. However, the S sludge material disposal system could include other means of disposing of the sludge material in a~,-' with El....~ ' Protection Agency (EPA) .~ ' For example, the sludge material disposal system could include a truck which transports the sludge to a remote area where it is spread out over the ground.
In any case, EPA ~cig ' frequently require accurate and recordirg of the amount of sludge which is being disposed.
In most instances, a sludge material handling sy.stem requires at least three or four " ' '- to monitor and control the sludge material feed system, the positive :" .' pump and the sludge rnaterial disposal system.
15 r .~, " a number of ". ' '~ to monitor and control the sludge material handling system adds significant cost to the disposal of sludge.
'" "~, pre,sent systems leave room for human error and makes it difficult to keep accurate records of the amount of sludge handled by the system. Keeping accurate records is typically necessary to satisfy EPA
SUluM~RY OF THF TNVFl~TION
The present invention is based upon the l. " that a sludge material handling system with a positive ~!5pl_ ' piston/cylinder pump, together with a system which d: the percent fill of the pump 25 qlinder(s) or actual volume of sludge delivered during a pumping qcle, offers the capability of ~ " _ the pump, 'l~
~ " _ a sludge material feed system which delivers sludge to the pump and "y . ~ " ~ a sludge material disposal system which receives and disposes of sludge from the pump.
CA21 i7~10 It is not normally possible to fill the glinder(s) of a positive :' ,' pump to 100~o of the }nown capacity. The sludge being pumped typically contains air and other . ~ materials. Therefore, a portion of each pumping stroke of the positive ~ ' pump involves 5 simply; , ~ ~ ,, the sludge in the grlinder before the pressurc driving the piston u. . the pressure at the outlet of the pump so that the sludge begins to flow out of the cylinder. In the present invention, at least one parameter related to operation of the positive ~' ,1; pump is sensed in order to identify the point during the pumping strolce when the hydraulic 10 pressure applied to the piston is sufficient to overcome the outlet pressure (so that sludge material begins to be pumped out of the glinder). From that ~ r '- , which bears a known L_~ ' ', to an actual volume of sludge delivered during a pumping gcle, the pump as well as upstream and down stream c . of the sludge material handling system may be The sludge material handling system of the present invention includes a positive ~ piston/glinder pump for pumping sludge through a pump outlet during each pumping stro~e. A sludge material feed system delivers sludge to a positive ~!q~_ ' pump inlet. The positive 20 ~I~sF~- pump delivers sludge through the pump outlet to a sludge material disposal system. A parameter is sensed during each pumping stroke, the parameter being related to operation of the pump and having a known ,.' ' to an actual volume of sludge delivered during the pumping stroke. An output value is ~' ' from the parameter sensed.
25 A control signal is provided as a function of the output value.
BP~TFF DFSC}~PI-ION OF T~TF. DRAWINGS
Figure 1 is a p.,~l~e.livc view, with portions bro~en away, of a sludge pump system which uses inlet and outlet poppet valves.
~ ~. 2 ~ ~ ~ J l 1~
S
Figure 2 is a bloc} diagram of a ~ system for d - and r ' ' volumes of sludge materials pumped by a positive :" . ' pump.
Figure 3 is a block diagram of a control system for ~h~ ' ,, S a sludge material handling system.
Figure 4 is a nOw chart which illustrates onc method of . " ~ material handling system 150 in the manner described above.
DpTAn Fn DF-ct~RnrFToN OF l~F pplP.FP.T~2Pn Fr~RoDTr~F~lTs A. OV~.T~VIP.W OF PUr 'P 10 Figure 1 shows a two qlinder h, ' '1~ driven positive d sl"- sludge pump 10 which could be used with the present invention. It should be noted, however, that other sludge pumps with variations in the _ q, of the hydraulic and control valve could bc used as well. Pump 10 includes inlets 12 and 14, outlet 16, material qlindcrs 18 and 20, material pistons 22 and 24, inlet poppet ~alves 26 and 28, outlet poppet valves 30 and 32, hydraulic inlet valve glinders 34 and 36, hydraulic outlet valve cylinders 38 and 40, poppet valve housing 42, hydraulic drive pistons 44 and 46, hydraulic glinders 48 and 50, hydraulic pump 52, high pressure lines 54, control valve assembly 56, hydraulic reservoir 58,1ow pressure line 60, folward and rear switching valves 62 and 64 and - 66.
High solids sludge material (sludge) is received at inlets 12 and 14, and is pumped through outlet 16, typically to a pipeline (not shown).
Material pistons 22 and 24 ,c.;~.~t. in material glinders 18 and 20. Inlet poppet valve 26 controls the ~ow of sludge from inlet 12 to material cylinder 18. Similarly, inlet poppet valve 28 controls the flow of sludge from inlet 14 to material glinder 20. The flow of sludge from glinders 18 and 20 to outlet 16 is controlled by outlet poppet valves 30 and 32, leD~ti.~
CA2i l 7~ 1 0 Inlet poppet valves 26 and 28 are controlled by hydraulic ir~et valve cylinders 34 and 36~ L._I~. Outlet poppet valves 30 and 32 are controlled by hydraulic outlet valve cylinders 38 and 40.
In the particular position shown in Figure 1, inlet poppet valve 5 26 and outlet poppet valve 32 are in an open position. This means that piston 22 is moving away from poppet valve housing 42, while piston 24 is moving toward poppet valve housing 42. Sludge is being drawn through inlet 12 and into cylinder 18, while sludge is being pumped from cylinder 20 to outlet 16.
Material pistons 22 and 24 are coupled to hydraulic drive pistons 44 and 46, l~L._I~, which move in hydraulic cylinders 48 and 50.
Hydraulic fluid is pumped from hydraulic pump 52 through high pressure lines 54 to control valve assembly 56. Although not shown in Figure 1, hydraulic pump 52 may be driven by an input shaft connected to a separate motor. Assernbly 56 includes throttle and checlc valves which control the 5 , ~ _ of high and low pressure hydraulic fluid to hydraulic qlinders 48 and 50 and to poppet valve cylinders 34, 36, 38 and 40. Low pressure hydraulic fluid returns to hydraulic reservoir 58 through low pressure line 60 from valve assembly 56.
Forward and rear switching valves 62 and 64 sense the position of piston 46 at the forward and rear ends of travel and are ~
to control valve assembly 56. Each time piston 46 reaches the forward or rear end of its travel in cylinder 50, a valve sequence is initiated which results in the closing of all four poppet valves and a reversal of the high pressure and low pressure - to cylinders 48 and 50.
The sequence of operations of pump 10 is generally as follows.
As drive pistons 44 and 46 and their connected material pistons 22 and 24 come to the end of their stroke, one of the material cylinders (in Figure 1, cylinder 20) is d~ material to outlet 16, while the other cylinder 18 - CA21:1 7~
is loading material from inlet 12. At the end of the pumping stroke, rnaterial piston 24 is at its closest point to poppet valve housing 42, while piston 22 is at its position furthest from poppet valve housing 42. At this point, switching valve 62 senses that hydraulic drive piston 46 has reached 5 the forward end of its stroke. Valve assembly 56 is activated which causes poppet valve cylinders 34 and 40 to be actuated. This causes inlet poppet valve 26 and outlet poppet valve 32 to close.
At this point, pistons 22 and 24 are at thc ends of their stroke, and their direction of movement is about to reverse. AU four poppet valves 26, 28, 30 and 32 are closed. Hydraulic pressure begins to increase in cylinder 48, which drives piston 44 forward. In t~n, piston 22 moves forward toward poppet valve housing 42. Piston 22, therefore, is now in a pumping or ~.' ' v ~ stroke. At the same time, hydraulic fluid located forward of piston 44 is being i ~ ~ d from qlinder 48 through 15 ~ . 66 to the forward end of cylinder 50. This applies hydraulic pressure to piston 46 to move it in a rearward direction. As a result, material piston 24 begins moving away from poppet valve housing 42 and it is in a loading or filling stoke. When the pressure in vah~e housing 42 below poppet vah~e 28 essentially equals the pressurc on the inlet side, poppet 20 valve 28 opens, which aUows sludge to flow through irllet 14 and into qlinder 20 during the fiUing stroke.
As piston 22 be~vins to move forward, it first . , ~ s the sludge within cylinder 18. At the moment when the . . - ~ sludge equals the pressure of the . . ~ d sludge in outlet 16, poppet valve 30 25 opens. Since the poppet valve for the d:~h~, cylinder opens only when the pressure of the content of a cylinder essentiaUy equals the pressure in the pipeline, no material can flow back.
The operation continues, with piston 22 moving for vard and piston 24 moving rearward until the pistons reach the end of their respective ~2 1 1 7~5 1 0 strokes. At that point, switching valve 64 causes valve assembly 56 to close all four poppet valves and reverse the . ~ of the high and low pressure fluids to qlinders 48 and 50. The operation continues with one material piston 22 or 24 operating in a filling stroke while the other is S operating in a pumping or discharge stroke.
It should be noted that pump 10 is one of several positive ILr pump ~ 5" which could be used with the present invention. For example, pump 10 could be of the type which uses a pivoting transfer tube valve, instead of poppet valves, to cormect the pumping 10 cylinder to the outlet during the entire pumping stroke. Detailed d - -of several positive :" ' pumps which could be used with the present invention may be found in Oakley et al., U.S. Patent No. 5,106,272, which is ' hereirl by reference.
B. MONITOP'T~G SYSTFr' 100 Figure 2 shows one possible e ~ ~- of a ~, system which mouitors the operation of pump 10 to provide accurate of the volume of sludge pumped on a . ~..le h, ~, _' - basis and on an ~s ' ~ basis. Monitor system 100 includes pump 10, computer 102, which in a preferred ' is a ~ based computer 20 including associated memory and associated input/output circuitry, clock 104,output device 106, input devioe 108, poppet valve se~rs 110, hydraulic flow rate se~rs 112, and hydraulic system se~rs 114.
Clock 104 provides a time base for computer 102. Although shown separately in Figure 2, clock 104 may be contained as part of 25 computer 102.
Output device 106 is preferably any of a number of devices.
For example output device 106 can include a display output such as a cathode ray tube or a liquid crystal display. Output device 106 can also be a printer, or a ~ device such as a cellular phone which CA2 i 1 7~ ~ ~
g transmits the output of computer 102 to another computer based system (which may monitor or control the overaD operation in which pump 10 is being used).
Input device 108 can also take a variety of forms. In one 5 preferred ~ ~' input device 108 is a ke~pad entry device. Input device 108 can also be a keyboard, a remote program device or any other suitable ' ~ for providing ~ r '- to computer 102.
Sensors 110, 112 and 114 monitor the operation of pump 10 and provide signals to computer 102. The l sensed by sensors 110, 10112 and 114 provide an indication of the percent fill of the pumping cylinder during each pumping stroke of pump 10, and allow computer 102 to determine the time period of each cycle. From this ' computer 102 .' ~ the volu ne of material pumped during that particular cycle, the r ' ' ~ volume pumped during a number of pumping cycles, the 15~ pumping rate and/or an average pumping rate over a selected period of time. Computer 102 stores the data in memory, and also provides signals to output device 106 based upon the particular ~ r - selected by input device 108.
In one preferred . ~ ' ~ the d~,i ~ of volume 20 pumped during a pumping cycle is as follows. Hydraulic system sensors 114 provide signals to computer 102 indicating the start time and stop time of each pumping stroke in pump 10. These signals are supplied to computer 102 by sensors 114 preferably in the form of interrupt signals.
Poppet valve sensors 110 sense when the outlet poppet valve 25 opens during the pumping stroke. The signal from poppet valve sensors 110 are also preferably in the form of an interrupt signal to computer 102.
Hydraulic flow rate sensors 112 are preferably located near hydraulic pump 52 and sense the flow rate of hydraulic fluid from pump 52.
Serlsors 112 are used to provide an indication to computer 102 that the - C-A 2 ~1 17~
velocity of pistons 22 and 24 has remained essentially constant during each pumping cycle. Signals from sensors 112 are preferably in the form of digitally converted analog signals to computer 102. In other preferred ' - ' if piston velocity is not intended to remain constant, sensors 112 are used to adjust the calculated volume of sludge purnped during each pumping stroke.
As pistons 22 and 24 travel through cylinders 18 and 20 during their respective pumping strokes, sludge in the qlinders is _ , ' When the sludge in a glinder is near fully . . i the pressure in that cylinder increases as piston 22 or 24 continues to move forvard in its pumping stroke. The time, during each pumping stroke, that an outlet poppet valve opens is ,.~ of the time that the piston (22 or 24) has built up sufficient pressure to push sludge out of the cylinder, through outlet 16, to a pipeline.
Computer 102, which receives signals from hydraulic systems sensors 114 indicating the start and stop times of each pumping strolce, and poppet valve sensors 110 indicating that sludge is being pumped out of the cylinder, ~ ~ a fill p~ by dividing the pumping stroke time after the poppet valve opens by the total pumping stroke time.
If hydraulic flow rate sensors 112 provide computer 102 with ~ ~ indicating that piston velocity did not remain essentially constant, r ~ are made to the calculated fill ~l. because this method of ~ fill pe.~ ~ is actually based upon the ratio of the length of the piston stroke after the poppet valve opens to the total stroke length.
Knowing the total ' l ' volume of the cylinder and the calculated pc,~ ~ fill during each pumping stroke, computer 102 calculates the actual volume pumped during each cycle. That value may be stored in a register within the memory of computer 102 and/or supplied to C ~ 2 ~
another computer which monitors system 100 and pump 10. In addition, computer 102 updates a register which keeps an r ' ' ~ total volume pumped.
Because computer 102 may also determine the length of time S during each qcle and the ~ time during which an r ' ' ~ li volume has been pumped, it is possible to calculate an pumping rate for each qcle, as well as an average pumping rate over the ~ time. All four values (volume pumped in a particular cycle, total - ' ~ volume, ~ pumping rate, and averagc pumping rate) can be calculated by computer 102.
It should be noted that monitor system 100 is one of many ~ v system . 5,, ~ which could be used to calculate a percent fill, or an actual volume of sludge pumped, during each pumping stroke. For example, ~nitor system 100 could include piston position sensors, instead lS of hydraulic system sensors 114, to notify computer lû2 of the start and stop times of each pumping stroke. Also, different ~ systems may be neoessary for different positive ~ pump . 5" Any ~ ~ system capable of ' ' . the peroent fill of each pumping stroke of a positive d srl- piston/qlinder pump could be for system 100 and used with the present invention.
C. ~T I JDG~ MATF.R-A- . HA~T .~G SYSTI~r ' 1~0 Figure 3 shows a preferred; ' - ' of sludge material handling system lS0 of the present invention. System lS0 includes monitor system 100 (including pump 10), computer 152, clock 154, output device 156, input devioe 158, sludge material feed system 160 and sludge material disposal system 162. In a preferred . ' ' t, computer 152 is a ~ u~J~u~r-based computer including associated memory and associated input/output circuitry. Clock 154 provides a time base for computer 152.
Although shown separately in Figure 3, clock 154 may be contained as part of computer 152. Output device 156 can include a display output such as a cathode ray tube or a liquid crystal display. Output device 156 can also be a printer, or a; ~ device sucb as a cellular phone which trar~nits the output of computer 152 to another computer based system.
5 Input device 158 can also take a variety of forms. In one preferred ~ ' input device 158 is a keypad entry device. Input device 158 can also be a keyboard, a remote program device or any other suitable - ' ~ for providirg ~ ~ to computer 152.
Although in Figure 3 computer 152, clock 154, output device 156 and input device 158 are shown separate from computer 102, clock 104, output device 106 and input device 108 of monitor system 100, in other preferred; ~ ' system 100 and system 150 are integrated and share these ~ , Sludge material feed system 160 can be any of a number of devices capable of drying sludge and/or supplying sludge to pump 10. For ex~nple, feed system 160 can be a oentrifuge which is used to dly sludge and supply it to pump 10 for pumping to sludge material disposal system 162.
Feed system 160 can also be a belt conveyer or a screw-type feeder. Feed system 160 can even include manual dumping, by a hurnan operator, of sludge into a hopper or intake area of purnp 10.
Sludge material disposal system 162 can be any device which disposes of sludge delivered by pump 10. In many instances, the disposal of sludge with disposal system 162 is regulated by the EPA. I~pically, disposal system 162 is an ~ ~ which ~ ~ the sludge delivered by pump 10 in acwl~ with EPA .~i" ' However, disposal system 162 can also be a truck which is loaded with sludge from pump 10 and which transports the sludge to another location for disposaL
D. DEl~.T~MINATION OF W~.TGHT OF SLUDGL
MAI~RTAT puMpT~n 7~J~ 0 EPA ,~,, ' often allow tbe disposal of only oertain quantities of sludge. These quantities may be based on volume, but instead, are frequently based on weight. System 150 can be used to determine the weight of sludge pumped during a single pumping cycle and an ?
5 weight pumped over a number of pumping cycles.
Typically, a user of system 150 }nows the weight per .' r unit of the particular sludge material being pumped. This is supplied to computer 152 through input devioe 158. Through output devioe 106, system 100 provides computer 152 with ~ r .~
0 IG~ of the volume of sludge pumped during a single purnping cycle, the ? ~ ' d volume pumped over a number of pumping cycles, the ~ ~' ~ pumping rate and the average ~ ' -pumping rate. Computer 152 d~; from this ' and from the weight per ~ unit, the weight of sludge pumped during a single 15 pumping cycle, the r ' ' weight pumped over a number of pumping cycles, the weight pumping rate, and the average weight pumping rate.
Clock 154 provides computer 152 with r " indicating the dates and times that the sludge is pumped. This r " is useful 20 in providing date stamped readouS, for the EPA, which verify dates and times of the disposal of quantities (by volume or weight) of sludge.
Computer 152 stores the above r " in memoq and provides signals to output device 156 based upon a particular r .~
format selected by input de~lioe 158. The date stamped r " ~ may be 25 recorded on a chart recorder, printed out in a report format or stored in a database for future use.
E. CONTROL OF PUMP 10. pFFn SYSTF.M 160 ANl~
DT~PO~L SYSTEM 162 CA2 1 i 751:3 Because handUng system 150, with the help of monitor system 100, can determine actual quantities (volume or weight) of sludge pumped by pump 10, system 150 can more easily control the 1~ Of sludge.
Based upon the percent fill of each qlinder as d~ ~ ' by monitor S system 100, computer 152 of handUng system 150 controls the operation ofany or all of pump 10, feed system 160 and disposal system 162. Control of feed system 160 can include; ~" the starting, the stopping and the rate of feed ~r Control of pump 10 can include . ~ starting and stopping of the pump. It can also include ~ ' the pump speed.
Control of disposal system 162 varies greatly depending on the particular type of disposal system used. For cxample, if system 162 includes an ~ , computer 152 can control the operating i . c, the amount of fuel used to incinerab the sludge, and other operating l of the .
In one preferred: ~ of the present invention, a user of material handling system 150 inputs, through input device 158, a maximum quantity of sludge to be processed by system 150. As discussed above, computer 152 d from the measured, ~ ' volume of sludge pumped by pump 10 and from the weight per ~ unit of the sludge, an r ' ~ weight of sludge pumped by pump 10 after each pumping stroke. When the - ~ ~ weight of sludge processed by system 150 equals the maximum quantity of sludge to be processed, computer 152 generates a control signal to control one or more of pump 10, feed system 160 and disposal system 162.
For example, the control signal can cause feed system 160 to stop delivering sludge to pump 10. In this case, computer 152 may also generate additional control signals to control pump 10 and/or disposal system 162. The addUtional control signals can be used to cause pump 10 to stop pumping and disposal system 162 to stop operating as well. However, in alternate ' ' one or both of pump 10 and disposal system 162 is allowed to continue operating after feed system 160 is stopped in order to clean out sludge remaining in the system.
While in preferred ~ ' ~ " ~ control signals are generated S to control pump 10, feed system 160 and disposal system 162, it sbould oe noted that any one of pump 10, system 160 and system 162 can be controlled alone by system 150.
For example, in one preferred ~ - of the present inventio4 a user inputs through input device 158 a desired rate at which pump 10 is to pump sludge to disposal system 162. Monitor system 100 provides computer 152 with the percent fill during each pumping stroke.
Based upon the percent fill during each pumping stroke or over a number of pumping strokes, computer 152 generates control signals which control the rate of which feed system 160 supplies sludge to pump 10. If the peroent fill is too low for pump 10 to pump sludge at the desired rate, the rate at which feed system 160 supplies sludge to pump 10 is increased. Iikewise, if the peroent fill is too high for pump 10 to pump sludge at the desired rate, the rate at which feed system 160 supplies sludge to pump 10 is decreased. This method of ~ " ~ matedal handling system 150 is illustrated in the flow chart shown in Figure 5.
In another preferred e ' ' t, disposal system 162 includes an ~ ~ which requires a known quantity of fuel to incinerate a given quantity of sludge. This ~ ' - is supplied to computer 152 by input device 158. Monitor system 100 provides computer 152 with the percent fill dudng each pumping stroke. Based upon the percent fill dudng each pumping stroke and over a number of pumping strokes, computer 152 generates control signals which control the rate and/or total quantity of fuel used by disposal system 162 while ~ ~ _ the sludge. One method of C A ~ 51 0 ~ ' g material handling system 150 in a~,, ~ with this preferred ~ is illustrated in the flow chart shown in Figures 6A and 6B.
In another preferred ~ " of the present invention, disposal system 162 also includes an ~ However, in this 5 ~ ~ - - t, there is a known ~ ~ . between the quantity of sludge material supplied to the and the i , c at which the - operates. This ~ is supplied to computer 152 through input device 158. An operator of system lS0 inputs, through input device 158, a desired i . c and the weight of the sludge per 10 ~ unit. Based upon the known ,~ ~ ~ . between the quantity of sludge material ~ and the l , c, computer 152 generates control signals which control one or both of feed system 160 and pump 10 so that a sufficient quantity of sludge is supplied to disposal system 162 to maintain the desired i . c.
In other preferred e ~ " control signals generated by computer 152 need not be based only on sensed r ' relating to an a~ual volume of sludge delivered during each pumping cycle. Computer 152 can also sense p related to the operation of feed system 160 and/or disposal system 162 and generate control signals based upon the 20 . ' of the actual volume of sludge deUvered during each pumping cycle and these p For example, in yet another preferred ~ _~ of the present invention which includes an in disposal system 162, computer 152 senses the operating t. ~l-- A~' -- C, compares it to a desired operating ~- c and ~: a difference between the sensed i . c and the desired .~
c. Next, computer 152 ~how much more or less sludge should be suppUed to disposal system 162 to obtain and maintain the desired A~ C. Based upon the quantity of sludge being delivered C-A2i ~7-51~
with each stroke of pump 10, computer 152 generates control signals which cause feed system 160 and pump 10 to increase or decreasc the rate at which sludge is delivered to disposal system 162. Two methods of ~ " ~ operation of material handling system 150 as a function of both S an aclual volume of sludge delivered and a parameter related to operation of sludge material feed system 160 or sludge material disposal system 162 are shown in the flow charts of Figures 7 and 8.
Although the present invention bas been described with reference to preferred: ~ " workers skilled in the art will recogr~ize 10 that changes may be made in form and detail without depar~ng from the spirit and scope of the invention.
Claims (33)
1. A method of controlling operation of a sludge material handling system, the sludge material handling system having a positive displacement piston/cylinder pump, having a sludge material feed system which delivers sludge material to the positive displacement pump, and having a sludge material disposal system which receives and disposes of sludge material from the positive displacement pump, the positive displacement pump having an inlet for receiving sludge material delivered by the sludge material feed system and an outlet through which sludge material is delivered to the sludge material disposal system under pressure, the sludge material received at the inlet being partially compressible such that a reduction in volume of the sludge material occurs during a pumping cycle as it is pumped from the inlet to the outlet, the method comprising:
sensing a first parameter, the first parameter being related to operation of the pump and bearing a known relationship to an actual volume of sludge material delivered during a pumping cycle;
determining from the sensed first parameter an output value;
and providing a control signal as a function of the output value.
sensing a first parameter, the first parameter being related to operation of the pump and bearing a known relationship to an actual volume of sludge material delivered during a pumping cycle;
determining from the sensed first parameter an output value;
and providing a control signal as a function of the output value.
2. The method of claim 1 wherein the sludge material feed system is controlled in response to the control signal.
3. The method of claim 2 wherein a rate at which the sludge material feed system delivers sludge material to the positive displacement pump is controlled in response to the control signal.
4. The method of claim 1 wherein the positive displacement pump is controlled in response to the control signal.
5. The method of claim 4 wherein a pumping speed of the positive displacement pump is controlled in response to the control signal.
6. The method of claim 1 wherein the sludge material disposal system is controlled in response to the control signal.
7. The method of claim 6 wherein the sludge material disposal system includes an incinerator which incinerates the sludge material.
8. The method of claim 1 further comprising:
sensing a second parameter, the second parameter being related to operation of the sludge material disposal system.
sensing a second parameter, the second parameter being related to operation of the sludge material disposal system.
9. The method of claim 8 wherein the control signal is also provided as a function of the second parameter.
10. The method of claim 9 wherein the sludge material disposal system includes an incinerator and the second parameter is related to an operating temperature of the incinerator.
11. The method of claim 1 further comprising:
sensing a second parameter, the second parameter being related to operation of the sludge material feed system.
sensing a second parameter, the second parameter being related to operation of the sludge material feed system.
12. The method of claim 11 wherein the control signal is also provided as a function of the second parameter.
13. The method of claim 1 wherein the output value represents an actual quantity of sludge material delivered by the pump during a pumping cycle.
14. The method of claim 1 wherein the output value represents an accumulated quantity of sludge material delivered by the pump during a plurality of pumping cycles.
15. The method of claim 14 wherein the sludge material handling system is controlled in response to the control signal in order to prevent the sludge material handling system from disposing of more than a predetermined quantity of sludge material.
16. The method of claim 1 wherein the output value represents a flow rate of sludge material delivered by the pump.
17. The method of claim 1 wherein the parameter sensed indicates a time following a beginning of piston movement when sludge material begins to flow out of the cylinder.
18. A control system for controlling a sludge material handling system, the sludge material handling system having a positive displacement piston/cylinder pump, having a sludge material feed system which delivers sludge material to the positive displacement pump, and having a sludge material disposal system which receives and disposes of sludge material from the positive displacement pump, the positive displacement pump having an inlet for receiving sludge material delivered by the sludge material feed system and an outlet through which sludge material is delivered to the sludge material disposal system under pressure, the sludge material received at the inlet being partially compressible such that a reduction in volume of the sludge material occurs during a pumping cycle as it is pumped from the inlet to the outlet, the method comprising:
means for sensing a first parameter, the first parameter being related to operation of the pump and bearing a known relationship to an actual volume of sludge material delivered during a pumping cycle;
means for determining from the sensed first parameter an output value; and means for generating a control signal as a function of the output value.
means for sensing a first parameter, the first parameter being related to operation of the pump and bearing a known relationship to an actual volume of sludge material delivered during a pumping cycle;
means for determining from the sensed first parameter an output value; and means for generating a control signal as a function of the output value.
19. The control system of claim 18 wherein the sludge material feed system is controlled as a function of the control signal.
20. The control system of claim 19 wherein a rate at which the sludge material feed system delivers sludge material to the positive displacement pump is controlled as a function of the control signal.
21. The control system of claim 18 wherein the positive displacement pump is controlled as a function of the control signal.
22. The control system of claim 21 wherein 8 pumping speed of the positive displacement pump is controlled as a function of the control signal.
23. The control system of claim 18 wherein the sludge material disposal system is controlled as a function of the control signal.
24. A method of controlling operation of a sludge material handling system, the sludge material handling system having a positive displacement piston/cylinder pump, having a sludge material feed system which delivers sludge material to the positive displacement pump, and having a sludge material disposal system which receives and disposes of sludge material from the positive displacement pump, the positive displacement pump having an inlet for receiving sludge material delivered by the sludge material feed system and an outlet through which sludge material is delivered to the sludge material disposal system under pressure, the sludge material received at the inlet being partially compressible such that a reduction in volume of the sludge material occurs during a pumping cycle as it is pumped from the inlet to the outlet, the method comprising:
providing a control signal as a function of a fill percentage of the pump; and controlling operation of the sludge material feed system as a function of the control signal.
providing a control signal as a function of a fill percentage of the pump; and controlling operation of the sludge material feed system as a function of the control signal.
25. The method of claim 24 wherein a rate at which the sludge material feed system delivers sludge material to the pump is controlled as a function of the control signal.
26. The method of claim 24 wherein controlling operation of the sludge material feed system includes controlling drying of the sludge material.
27. The method of claim 24 further comprising:
controlling operation of the sludge material disposal system as a function of the control signal.
controlling operation of the sludge material disposal system as a function of the control signal.
28. A method of controlling operation of a sludge material handling system, the sludge material handling system having a positive displacement piston/cylinder pump, having a sludge material feed system which delivers sludge material to the positive displacement pump, and having a sludge material disposal system which receives and disposes of sludge material from the positive displacement pump, the positive displacement pump having an inlet for receiving sludge material delivered by the sludge material feed system and an outlet through which sludge material is delivered to the sludge material disposal system under pressure, the sludge material received at the inlet being partially compressible such that a reduction in volume of the sludge material occurs during a pumping cycle as it is pumped from the inlet to the outlet, the method comprising:
providing a control signal as a function of a fill percentage of the pump; and controlling operation of the sludge material disposal system as a function of the control signal.
providing a control signal as a function of a fill percentage of the pump; and controlling operation of the sludge material disposal system as a function of the control signal.
29. The method of claim 28 wherein a rate at which the sludge material disposal system disposes of sludge material is controlled as a function of the control signal.
30. The method of claim 28 wherein the sludge material disposal system includes an incinerator which incinerates the sludge material.
31. The method of claim 28 further comprising:
controlling operation of the sludge material feed system as a function of the control signal.
controlling operation of the sludge material feed system as a function of the control signal.
32. A method of controlling operation of a sludge material handling system, the sludge material handling system having a positive displacement piston/cylinder pump, having a sludge material feed system which delivers sludge material to the positive displacement pump, and having a sludge material disposal system which receives and disposes of sludge material from the positive displacement pump, the positive displacement pump having an inlet for receiving sludge material delivered by the sludge material feed system and an outlet through which sludge material is delivered to the sludge material disposal system under pressure, the sludge material received at the inlet being partially compressible such that a reduction in volume of the sludge material occurs during a pumping cycle as it is pumped from the inlet to the outlet, the method comprising:
determining a fill percentage of the pump based upon a parameter related to operation of the pump; and controlling operation of the sludge material feed system as a function of the fill percentage determined.
determining a fill percentage of the pump based upon a parameter related to operation of the pump; and controlling operation of the sludge material feed system as a function of the fill percentage determined.
33. A method of controlling operation of a sludge material handling system, the sludge material handling system having a positive displacement piston/cylinder pump, having a sludge material feed system which delivers sludge material to the positive displacement pump, and having a sludge material disposal system which receives and disposes of sludge material from the positive displacement pump, the positive displacement pump having an inlet for receiving sludge material delivered by the sludge material feed system and an outlet through which sludge material is delivered to the sludge material disposal system under pressure, the sludge material received at the inlet being partially compressible such that a reduction in volume of the sludge material occurs during a pumping cycle as it is pumped from the inlet to the outlet, the method comprising:
determining a fill percentage of the pump based upon a parameter related to operation of the pump; and controlling operation of the sludge material disposal system as a function of the fill percentage determined.
determining a fill percentage of the pump based upon a parameter related to operation of the pump; and controlling operation of the sludge material disposal system as a function of the fill percentage determined.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US08/113,841 | 1993-08-30 | ||
| US08/113,841 US5336055A (en) | 1990-10-10 | 1993-08-30 | Closed loop sludge flow control system |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2117510A1 CA2117510A1 (en) | 1995-03-01 |
| CA2117510C true CA2117510C (en) | 2002-07-02 |
Family
ID=22351831
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2117510 Expired - Lifetime CA2117510C (en) | 1993-08-30 | 1994-08-16 | Closed loop sludge flow control system |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2117510C (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP3347774A1 (en) * | 2015-09-11 | 2018-07-18 | Henkel IP & Holding GmbH | Remote adhesive monitoring system |
-
1994
- 1994-08-16 CA CA 2117510 patent/CA2117510C/en not_active Expired - Lifetime
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP3347774A1 (en) * | 2015-09-11 | 2018-07-18 | Henkel IP & Holding GmbH | Remote adhesive monitoring system |
| EP3347774A4 (en) * | 2015-09-11 | 2019-05-08 | Henkel IP & Holding GmbH | Remote adhesive monitoring system |
| US10421097B2 (en) | 2015-09-11 | 2019-09-24 | Henkel Ag & Co. Kgaa | Remote adhesive monitoring system |
Also Published As
| Publication number | Publication date |
|---|---|
| CA2117510A1 (en) | 1995-03-01 |
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