CA1286344C - Product pump system - Google Patents

Abstract

Abstract of the Disclosure A product pump system having a compressed product pump for conveying dry free-flowing material. The product pump has a product chamber, a product receiving inlet communi-cating with the product chamber, a product discharge outlet communicating with the product chamber, and a pressurized air inlet also communicating with the product chamber.
A receiving inlet valve is connected to the product receiving inlet for regulating the flow of product through the product receiving inlet into the product chamber. An air inlet valve is connected to the pressurized air inlet for regulating the flow of compressed air into the product chamber. The pressurized air inlet means includes an upper and lower air inlets. The upper inlet is positioned so that the pres-surized air passing through it generally impacts the upper portion of the product in the product chamber when filled and also pressurizes the product chamber. The lower air inlet is positioned so that the pressurized air passing through it sweeps the product on the floor of the product chamber out through the product discharge outlet. A vent communicates with the product chamber through an upper pump surface and vents the product chamber after the product in the chamber has been discharged out through the product discharge outlet and after the air inlet valve has closed the pressurized air inlet. A venting line valve regulates the flow of air from said product chamber out through the vent.

Description

~2~i3 14 PRODI~CT P[~MP SYSTEM

This invention relates to product pumps that move product from the discharge of a hopper, bin, silo or other product container and deliver the product to one or more collecting points by means of a dense-phase, positive-pressure, pneumatic conveying system, and the entire product pump assemblies for doing this. It more particularly relates to pump assemblies used to discharge into pressurized vessels or into liquids that cause a high system back pressure. It also relates to such pump assemblies which can be used to convey products that are light and fluffy or otherwise have poor flow characteristics.
Small quick cycling product pumps were frequently used as a means of introducing a product into a pneumatic conveying line. Each successive cycle of the pump pushed a new charge of product into the conveying line and the air trapped between each charge pushed the previously-loaded charge further along the conveying line. These devices are normally cycled with electric or pneumatic controls incorporating adjustable timing devices.
The timers are arranged to vary the time of each function within the cycle so that the system can be adjusted to meet varying field conditions. The cycle starts with the product inlet valve open and product flows by gravity from the hopper, or the like, into the product pump. After a short full time, the product inlet valve is closed and the air pressure is app]ied to the pump chamber to force the product charge from the pump into the conveying line. After the air flow is shut off, air pressure remains . . . . . . . . . . . . . . . . . . . . . . . . . . . .

~2863~

in the product pump and in the conveying line. Some of this air will dissipate through the product charge and out the discharge of the conveying system providing a delay time is employed between the compressed air shut off the opening of the product inlet valve. In actual practice, a delay time is selected that permits some compressed air to bleed off down the pipe with the remaining compressed air blowing up into the product when the inlet valve is opened. Both the time required to bleed off the compressed air and the air blowback reduce the overall delivery rate of the pneumatic conveying system. Additionally, the higher the back pressure at the discharge of the system, the greater the inlet venting problem. Also, a high rate of blowback at the inlet feed point often causes a dust problem. It is further noted that this type of system cannot be used to transport to a pressurized vessel or into a liquid that presents a large hydraulic back pressure.

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1~:l363~4 Object of the Invention Accordingly, it is the principal object of the present invention to provide an improved means for moving product by dense-phase positive-pressure pneumatic-conveying means from a storage container to a collecting point.
Another object of the present invention is to provide a novel conveying system which can effectively convey products that are light and fluffy or otherwise have poor flow character-istics.
A further object of the present invention is to provide a novel system that uses pressurized air to discharge the product into a high pressurized vessel or into a liquid that causes a high system back pressure.
A still further object of the present invention is to provide a novel conveying system which eliminates or minimizes the dust problems previously experienced.
A further object is to provide a novel product pump system which has an adequate filling of the product chamber and improved conveying cycling rate.
A further object is to provide an improved compressed air pump having superior product delivery rates.
A still further object is to provide a novel pump system with excellent efficiencies for pumping a variety of products.
Another object is to provide an improved pump which has excellent pumping efficiency for a variety of system piping arrangements.
A further object is to provide a novel pump assembly which can be readily adjusted to insure peak delivery efficiency.

A still furthèr object is to provide an improved pump system which completely discharges the product out of the ~Z~3 ~

pressure pot or chamber without leaving a heel of material in the chamber.
A still further object is to provide an improved compressed air pump which efficiently delivers light and/or fluffy dry free-flowing products.
Other objects and advantages of the present invention will become more apparent to those persons having ordinary skill in the art from the following description taken in conjunction with the accompanying drawings.

lZ863'~4 Brief Description of the Drawings Figure 1 is a side elevational view of a product pump system embodying the present inven~ion.
Figure 2 is an end elevational view of the system of Figure 1.
Figure 3 is an enlarged perspective view of the pump of the system of Figure 1 illustrated in isolation.
Figure 4 is an electrical schematic of the timing control means for the product pump system of Figure 1.
Figure 5 is a front view of the control panel for the control means of Figure 4.
Figure 6 is a schematic of the field wiring for the panel of Figure 5.
Figure 7 is a view of the engraved nameplates of the panel of Figure 5.

lZ~63~4 Description of the Preferred Embodiment Referring to Figures 1 and 2, a product pump system embodying the present invention is illustrated generally at 10. System 10 basically includes a product source or hopper 12 leading down into a product pump 14. A compressed air supply or source shown generally at 16 pumps air through product pump 14 through a two-inch delivery line 18 delivering the product to a product collector 20. System lo can effi-ciently deliver a wide range of dry free-flowing products, such as wheat flour, plastic compounds, powders, pellets, and finely divided clays, from hopper 12 to product collector 20.
Product pump 14 is best illustrated in Figure 3 wherein it is shown in isolation and it defines an interior product ' pot or chamber 22. Product pump 14 has a product receiving inlet 24 on its upper surface having a mounting flange 26 surrounding it. At one end of the product pump 14 is the product discharge outlet 28 which is secured to and communicates directly with delivery line 18. At the opposite end a pair of compressed air inlets is provided, each communicating with compressed air source 16, and, as shown, comprising an upper air inlet 30 positioned directly above a lower air inlet 32. A venting pipe 34 exits through an upper surface of product pump 14 and it also has a mounting flange 36 at its end for mounting to a venting valve.
The compressed air for system 10 is supplied to the air inlets by compressed air source 16, which usually will be from the compressed air source of the system user's plant, and which typically will be at a pressure of sixty to one hundred and twenty psi. The air is supplied through a com-pressed air supply line 40 to the pressure regulator 42 where the pressure is dropped down to the pump operating ~L2~6344 pressure of twenty to fifty pounds and held there. Heavier products and longer conveying distances require greater pressures. From the regulator the air flows to pressurized solenoid air valves 44, 46 which control the flow of the compressed air into upper and lower air inlets 30, 32.
As will later be described more fully, these air valves are opened and closed together so that the air passes through both of the inlets into the chamber at the same time. However, it is also within the scope of the invention to have upper air inlet 30 open before lower air inlet 32. Upper air inlet 30 enters product chamber 22 at an upper location such that the pressurized air exiting therefrom will impact the upper portion of the product when chamber 22 is full.
The compressed air from upper air inlet 30 also pressurizes the entire chamber 22 and thereby forces the product out through product discharge outlet 28. Lower air inlet 32, on the other hand, is positioned so that compressed air passing therethrough will be generally adjacent the floor of product chamber 22 and sweep the product out through product discharge outlet 28, thereby preventing a heel of material from being left in chamber 22. Thus, this novel dual inlet system provides for the thorough and quick discharge of the product from product chamber 22 out product discharge outlet 28.
The product, when forced by the compressed air out product discharge outlet 28, travels through delivery line 18 past a check valve 48 into product collector 20. Product collector 20 may comprise a liquid tank or vessel having a positive pressure exerting a back pressure through delivery line 18. To prevent the product from flowing back into product chamber 22, when air valves 44, 46 have been closed, by the force of this back pressure, check valve 48 is provided .

,i lZ863~4 and mounted in delivery line 18. The details of the construc-tion of check valve 48 are set forth in the aforementioned parent application. However, any suitable directional valving means may be used.
The product is stored in hopper 12 positioned directly over product pump 14. Hopper 12 communicates through product receiving inlet 24 with chamber 22, and product receiving inlet valve 50 controls the flow of the product into chamber 22. The product, which is dry, free-flowing material and can be very light and fluffy, gravity flows from hopper 12 through inlet valve 50 when open and into chamber 22.
! Venting pipe 34 exits from the upper side surface of the product chamber and is controlled by a vent valve 52, such as a butterfly gate which has quick opening and closing characteristics, mounted to mounting flange 36. Vent valve 52 is opened after the pressurized air inlet valves 44, 46 have closed and before product receiving inlet valve 50 has opened. Venting pipe 34 allows the excess pressure to drain out of chamber 22 so that air is not released through receiving inlet 24 which, as has been experienced in the past, creates a dust condition and reduces the flow rate of the product into the chamber. The venting helps zero ; the pressure in the chamber, so that lighter products, such as those lighter than ten pounds per cubic foot, can be used and can gravity flow into the chamber. If vent valve i 52 opens too early, the product is conveyed up vent line ~ , .
34. If the venting time is set too short, then air vents through product receiving inlet 24 when receiving inlet valve 50 opens. The product delivery rate is dependent ;

~ on the adequate filling of product chamber 22 and the number ;: :~

lZ~63 ~4 of conveying cycles per minute. Adequa~e venting allows the product to flow freely into product chamber 22 to permit a shorter fill time. Excessive vent time, on the other hand, reduces the overall conveying rate by extending the time required for each cycle. Thus, vent valve 52 opens, then product inlet valve 50 opens and after filling is completed, they both close.
Ideally, check valve 48 should be positioned adjacent product pump 14. However, because of the presence and configur-ation of hopper 12, as best shown in Figure 1, check valve 48 must be positioned a short distance away from chamber 22. Thus, in addition to chamber 22, the portion of delivery line 18 between check valve 48 and chamber 22 must also be vented by ventiny pipe 34. Venting pipe 34 vents into a suitable filtering device shown generally at 54 in Figure 2. Filtering device 54 can be any suitable device such as the "Self-contained Filter Bag Dump Station," manufactured by The Young Industries of Muncy, Pennsylvania. It is also noted that when the top of the product source is equipped with a dust collector and negative draw fan, the negative pressure will assist venting pipe 34 to remove the excess pressure out of product chamber 22 and will also provide additional dust control.
The product delivery rate of system 10 is maximized by the use of a novel electrical timing means for controlling the operation of each of the valves. The wiring circuit for this sequence is shown in Figure 4 generally at 58, and is mounted in the electrical sequencing control panel 60 positionable adjacent hopper 12. The operating cycle starts when control panel 60 is placed in the "automatic"
position. Product receiving inlet valve 50 opens and the fill timer TDl is energizeæ. When timer TDl times out and it has a normal setting of .4 to 1.0 seconds, inlet valve 50 and vent valve 52 close and the timer TD2 is energized.
This timer provides a delay for opening the pressurized air valves 44, 46 to allow inlet valve 50 and vent valve 52 to completely close and has a normal setting of o.l to O . 2 seconds. When timer TD2 times out, air valves 44, 46 open, conveying of the product starts and timer TD3 is ener-gized. When timer TD3 times out and it has a normal setting of 0.3 to 0.8 seconds, pressurized air valves 44, 46 close and vent timer TD4 is energized. When timer TD4 times out and it has a normal setting of 0.3 to 0.5 seconds, vent valve 52 opens and timer TD5 is energized. Then when timer TD5 times out and it has a normal setting of 0.5 to l.o seconds, inlet valve 50 opens and the cycle is repeated until the panel manual, off, automatic switch as shown in Figure 7 is placed in the "off" position. The manual position of the switch provides a means, by pressing PBl and PB2 as shown in Figure 5, of manually filling and conveying the product. The "manual" position provides a method of purging system 10 prior to shutdown.
The sequencing timer may be either electrically or pneumatically controlled with the timing devices arranged for manual adjustment of each function of the complete cycle.
The combined use of check valve 48, venting pipe 34 with a fast acting vent valve 52 and the electrical means of precise control of the sequencing timers 58 makes product pumping system 10 extremely efficient. System 10 has an excellent product delivery rate of at least one hundred cubic feet per hour, which is generally twice that previously possible. This superior system efficiency can be maintained for a wide variety of product characteristics and system ', 12~

piping arrangement. The sequence control further permits product pump system 10 to be easily adjusted to ensure peak efficiency.
From the foregoing detailed description, it will be evident that there are a number of changes, adaptations and modifications of the present invention which come within the province of those skilled in the art. However, it is intended that all such variations not departing from the spirit of the invention be considered as within the scope thereof as limited solely by the appended claims.

Claims (37)

1. A product pump system comprising:
a product pump having a product chamber, a product receiving inlet communicating with said product chamber, a product discharge outlet communicating with said product chamber, and a pressurized air inlet communicating with said product chamber, a receiving inlet valve connected to said product receiving inlet for regulating the flow of product through said product receiving inlet into said product chamber, an air inlet valve connected to said pressurized air inlet for regulating the flow of compressed air through said pressurized air inlet into said product chamber, and a venting means generally spaced from said product receiving inlet, from said product discharge outlet, and from said pressurized air inlet, and communicating with said product chamber for venting said product chamber after the product in said product chamber has been generally dis-charged out through said product discharge outlet and said air inlet valve has closed said pressurized air inlet.

2. The system of Claim 1 including, said venting means including a venting line communi-cating with said product chamber and a venting line valve connected to said venting line for regulating the flow of air from said product chamber out through said venting line.

3. The system of Claim 2 including, said venting means including a controlling means connected to said venting line valve for opening said venting line valve only when said air inlet valve is closed.

4. The system of Claim 3 including, said controlling means closing said venting line valve after said receiving inlet valve has opened and product has started to pass through said product receiving inlet into said product chamber.

5. The system of Claim 2 including, said venting line communicating with said product chamber on an upper surface thereof.

6. The system of Claim 2 including, said venting means further including a filter device attached to said filtering line, and said venting line valve being positioned on said venting line between said filter device and said product chamber.

7. The system of Claim 2 including, a timed controlling means operatively connected to said receiving inlet valve, said air inlet valve, and said venting line valve and automatically controlling their relative timed regulating operations.

8. The system of Claim 7 including, said timed controlling means including first, second, third, fourth, and fifth timers.

9. The system of Claim 8 including said timed con-trolling means further including, a means for energizing said first timer, when said receiving inlet valve is open, for a first set period of time, a means for, immediately after said first timer has timed out, closing said receiving inlet valve and said venting line valve and energizing said second timer for a second set period of time, a means for, immediately after said second timer has timed out, opening said air inlet valve and energizing said third timer for a third set period of time, a means for, immediately after said third timer has timed out, closing said air inlet valve and energizing said fourth timer for a fourth set period of time, a means for, immediately after said fourth timer has timed out, opening said venting line valve and energizing said fifth timer for a fifth set period of time, and a means for, immediately after said fifth timer has timed out, opening said receiving inlet valve.

10. The system of Claim 9 including, said first, second, third, fourth, and fifth set periods of time totalling generally between two and two and a half seconds.

11. The system of Claim 9 including, said first set period of time being between .4 and 1.0 seconds, inclusive, said second set period of time being between .1 and .2 second, inclusive, said third set period of time being between .3 and .8 seconds, inclusive, said fourth set period of time being between .3 and .5 seconds, inclusive, and said fifth set period of time being generally between .5 and 1.0 seconds, inclusive.

12. The system of Claim 11 including, said first, second, third, fourth, and fifth set periods of time totalling between two and two and a half seconds.

13. The system of Claim 7 including, said timed controlling means being electrically controlled.

14. The system of Claim 7 including, said timed controlling means being pneumatically controlled.

15. The system of Claim 1 including, a pressurized vessel into which said product pump conveys the product through said product discharge outlet.

16. The system of Claim 15 including, a check valve positioned between said pressurized vessel and said product discharge outlet for preventing the flow of the product back into said product chamber.

17. An apparatus for handling comminuted material comprising:
means defining a zone into which said material may be deposited, filter means having an inlet communicating with said material depositing zone, pump means defining a chamber for receiving material from said material depositing means, valve means for controlling the supply of material from said material depositing means to said pump chamber, means for injecting a fluid under pressure into said pump chamber to flush material disposed therein through a pump outlet, valve means for controlling the supply of fluid into said pump chamber, venting means intercommunicating said pump chamber and the inlet of said filter means, and valve means for controlling the flow of fluid through said venting means.

18. An apparatus according to claim 17 including control means operable to sequentially close said fluid supply valve means while opening said material supply valve means for supplying a batch of material to said pump chamber, close said material supply valve means and said venting valve means while opening said fluid supply valve means for flushing said batch of material out of said pump chamber through said pump outlet and then open said venting valve means while closing said fluid supply valve means and maintaining said material supply valve means closed for venting said pump chamber.

19. An apparatus according to Claim 18 wherein said control means is electrically operated.

20. An apparatus according to Claim 17 wherein said means for injecting fluid under pressure into said pump chamber includes a first means for injecting a stream of fluid into an upper region of said pump chamber and second means for injecting a stream of fluid into a lower region of said pump chamber.

21. An apparatus according to Claim 20 including means for controlling said fluid supply valve means to operate said first and second injection means sequentially.

22. An apparatus according to Claim 17 wherein said material depositing means comprises a hopper.

23. An apparatus according to Claim 22 wherein said hopper is provided with a bottom discharge outlet communicating with said material supply valve means for supplying material to said pump chamber by gravity flow.

24. An apparatus according to Claim 17 wherein said filter means includes means for drawing air from said material depositing zone.

25. An apparatus according to Claim 17 wherein said filter means includes suction means and a filter medium disposed between the inlet thereof and said suction means, and wherein said venting means communicates with said filter means at a location between the inlet and filter medium thereof.

26. An apparatus according to Claim 25 wherein said suction means comprises a centrifugal fan.

27. An apparatus according to Claim 26 wherein said valve means are solenoid actuated valves.

28. An apparatus according to Claim 17 including material conveying means intercommunicating the outlet of said pump means and a material collector means.

29. An apparatus according to Claim 28 including a check valve disposed in said material conveying means.

30. An apparatus according to Claim 17 including control means for opening said venting valve means only when said fluid supply valve means is closed.

31. An apparatus according to Claim 30 wherein said control means is operable to close said venting valve means after said material supply valve means is open and material has begun to flow into said pump chamber.

32. An apparatus according to Claim 18 wherein said control means is operable in a predetermined timed sequence.

33. An apparatus for handling a communited material comprising:
means defining a zone open to the atmosphere into which said material may be deposited, pump means defining a chamber for receiving material from said material depositing zone, valve means for controlling the supply of material from said material depositing zone to said pump chamber, means for injecting a fluid under pressure into said pump chamber to flush material deposited therein out through a pump outlet, valve means for controlling the supply of fluid into said pump chamber, venting means intercommunicating said pump chamber and said material depositing zone, and valve means disposed in said venting means operable in an open condition when said fluid supply valve means is in the closed condition to communicate said pump chamber with said material depositing zone and in a closed condition when said fluid supply valve means is in an open condition to preclude communication of said pump chamber with said material depositing zone.

34. An apparatus according to Claim 33 including control means operable to sequentially close said fluid supply valve means while opening said material supply valve means for supplying a batch of material in said pump chamber, close said material supply valve means and said vent valve means while opening said fluid supply valve means for flushing said batch of material out of said pump chamber through said pump outlet and then open said vent valve means while closing said fluid supply valve means and maintaining said material supply valve means closed for venting said pump chamber.

35. An apparatus according to Claim 33 wherein said means for injecting fluid under pressure into said pump chamber includes a first means for injecting a stream of fluid into an upper region of said pump chamber and second means for injecting a stream of fluid into a lower region of said pump chamber.

36. An apparatus according to Claim 35 including means for controlling said fluid supply valve means to operate said first and second injection means sequentially.

37. An apparatus according to Claim 33 including a check valve disposed in an outlet of said pump means.