GB2054502A - Conveying flowable material by suction and pressure - Google Patents

Abstract

A method or an apparatus for conveying flowable material, for example, pulverised fuel ash or heavy oils or slurries, by utilising two cyclone separators 1 and 2, the suction for which is derived from a liquid ring pump 5, valves 27, 28 being provided for controlling the flow of material to draw material into the cyclone separators from which the material is discharged by pressure from a compressor 8 via valves 46, 47, the arrangement being such that whilst material is being sucked into one separator it is being discharges from the other. The cyclone separators are jointly connected to a third cyclone separator which enables the light fraction to be further separated and the liquid ring pump being in a liquid circuit with a water separation tank whereby any particulate material which finds its way into the water circuit will be separated out. All the valves are pneumatically operated from a compressor driven by a diesel engine. <IMAGE>

Description

SPECIFICATION A method of and apparatus for conveying flowable material Description This invention relates to a method of an apparatus for conveying flowable material. As examples of what is meant by flowable material can be mentioned cement, pulverised fly ash, coal, coke, mill scale, sand aggregates, catalysts, blasting shot and grit, abrasives, grain, lime, digested sewage, detritus, slag, sludges and slurries, water, oil sludge, wax or any other granular, liquid or semi-liquid materials.

Such flowable materials niay be conveyed from silos, tanks, digestors, ships, holds, barges, hoppers, precipitators, flues, screens, settling beds, sewers, elevators, clarifers, filter beds, mill beds, elevated areas, furnaces, or fixed installation applications. By virtue of the invention, these materials may be conveyed from one location to another for a total distance of up to 300 metres, depending on the bulk density of the material to be handled.

According to the present invention there is provided a method of conveying flowable material from a first location to a second location, which includes drawing the material under suction from the first location into a first container by opening a suction line to the first container, closing the suction line to the first container and opening the suction line to a second container to continue the drawing of the material from the first location, and thereafter alter naming the opening and closing of the suction line to the containers; on the suction line being closed to one said container, opening a pressure line to said container to pressurize the material therein and then opening a discharge valve of said container to convey the material under pressure through a discharge line to the second location; and thereafter alternating the opening of the pressure line to said containers and opening the discharge valves to convey material under pressure to the second location; the suction input to the containers or the pressure discharge from the containers being continuous.

Preferably, the method as aforesaid includes the containers being cyclone separators and as material is drawn into the containers, the material is subjected to separation of heavy and light fractions, the heavy fraction being discharged under pressure.

The invention also includes apparatus for conveying flowable material from a first location to a second location, including two containers having a common inlet line and valves for controlling the flow of material to each container, a suction line common to both containers and valves for controlling the suction from each container, an outlet line common to both containers and valves for controlling the outlet from each container, and an air pressure line and valves for controlling the supply of air under pressure to each container.

Preferably, the suction is provided by a liquid ring pump.

Preferably, the containers are cyclone separators which receive te material tangentially and discharge the heavy fraction at the base and the light fraction at the top, the light fraction being sucked to a third cyclone separator for further extraction.

One embodiment of apparatus according to the invention will now be described, by way of example only, and with reference to the accompanying drawings in which: Figure 1 is a side elevation of apparatus constructed in accordance with the invention; Figure 2 is a plan view of Figure 1; Figure 3 is an end view of Figure 1; and Figure 4 is a schematic layout of the apparatus of Figures 1 to 3.

Referring to the drawings, there is provided first and second containers in the form of first and second cyclone separators 1 and 2 and a third cyclone separator 3 below which is a material collection vessel 4. A liquid ring pump 5 is driven by a diesel engine 6 through a suitable transmission mechanism 7, the engine 6 also driving a compressor 8 and a fan 9.

The liquid pump 5 discharges a mixture of air and water through pipe 10 to a separation tank 11 having a sludge bottle 12 connected to th base thereof. The tank 11 leads, via pipe 13, to radiator 14 cooled by the fan 9. Water flows from the radiator 14to a header tank 15, the level of which is controlled buy a float 16 operating an inlet valve. Water flows from the header tank, via pipe 17, back to the pump thus completing the water circuit.

The entire apparatus is mounted on a chassis 18 on road wheels 19 with a hitch 20 for towing purposes.

There are two connections 21 and 22 at one end of the vehicle. The connection 21 is to connect a vacuum hose. This is the suction connection and leads via common pipe 23 to a fork 24 and short pipes 25 and 26 through valves 27 and 28 to convey material tangentially into the cyclone separators 1 and 2 respectively.

At the base of the cyclone separators 1 and 2 are axial outelts 29 and 30 respectively controlled by valves 31 and 32 respectively. Also at the bases of the separators 1 and 2 are pressure lines 33 and 34 respectively incorporating valves 35 and 36 respectively. These pressure lines 33 and 34 lead to a common pressure line 37 which leads to the pressure discharge connection 22 and a pressure hose.

Leading axially from the top of the separators 1 and 2 are suction lines 38 and 39 respectively, which via valves 40 and 41 respectively, lead to a common suction line 42 which leads tangentially into the third cyclone separator 3.

At the base of the third separator 3 is a time controlled valve 43 leading to the material collection vessel 4. Extending axially from the top of the third separator 3 is a pipe 44 which leads to the pump 5 which is the source of suction.

The compressor 8 is connected to air pressure reservoir 45 and builds up pressure therein for feeding air under pressure to the separators 1 and 2 via valves 46 and 47 respectively. The material collection vessel 4 is provided with a valve 48 for venting to atmosphere and with a valve 49 at the base thereof which leads via pipe 50 into the common inlet line 23 for recirculating material.

In the line 44 is a valve 51 which enables the pump to be vented to atmosphere if the separators 1 and 2 are both full. The valve 51 also acts as a pressure relief valve should air escape from separators 1 or 2.

In operation the apparatus works as follows.

The apparatus is drawn by a vehicle to an appropriate site and a suction hose is coupled to connection 21. The free end of the suction hose is in the area of the material to be conveyed i.e. the first location. A pressure discharge hose is connected to connection 22 the free end of this hose being at the second location where ever the material is to be conveyed to. The suction hose may be anything up to 70 metres in length and the discharge hose up to 230 metres in length making the total conveying distance in the order of 300 metres.

The diesel engine 6 is started and the compressor 8 and liquid ring pump 5, together with the fan 9, are driven.

To fill separator 1, valves 27 and 40 are opened and valves 46, 35 and 31 are closed. Initially, all the valves concerned with separator 2 are in the closed position, namely, valves 28, 41, 47, 32 and 36.

The liquid ring pump generates a suction of 27 inches of mercury through pipes 44, 42 and 38 and the suction transports the material from the first location into the separator 1.

It is possible to operate the valve mechanism by the actuation of sensors within separators 1 and 2 which sense the level of material within the separators. However, this is not preferably and the preferable way is to time the period of flow. Such timer may be preset dependent upon the flow rate and the type of material being conveyed. For very fine particulate material, the apparatus can generate a flow rate of 1,100 cubic feet per minute.

As soon as separator 1, is full, the valves 27 and 40 close and valves 28 and 41, which are concerned with separator 2, open. This means that the suction is still present in the suction pipe 23 and material starts to flow into separator 2. The valve 46 of separator 1 now opens and air under pressure from storage reservoir 45, is injected into separator 1 until a preset pressure of 40 to 60 psi is reached. At this stage, the valve 35 is opened and the material in separator 1 is discharged until all the material in separator 1 has been ejected and there is zero pressure in this separator. However, the apparatus may be set so that the valve 35 closes when the pressure in separator 1 is one or two psi.

Alternatively, instead of pressurizing the material out via the outlet line 37, the valves 31 and 32 may be opened and the material discharged vertically by gravity through outlets 29 and 30. A skip or other container may be positioned below the outlet 29 or 30 to receive the material.

During the time when separator 1 is being discharged, the separator 2 is being filled with material until such time as this is full. The valves 28 and 41 will then close and the valve 47 will open allowing pressure to build up inside the separator 2 until the desired pressure of 40 to 60 psi has been reached whereupon valve 36 will open and discharge the material from separator 2. The operation will continue, simuitaneously charging one separator and discharging the other in succession.

As will be appreciated, the type of material being handled may mean that the container being filled is full before the container being emptied is empty, in which case the pump 5 will have to be vented to atmosphere through valve 51 to conserve energy.

On the other hand, it may be that the nature of the material being conveyed is that the separator being filled is only partially filled before the container being discharged is fully empty, in which case the time mechanism will be adjusted so that the valves do not change their state until such time as the separator being filled is full.

When the type of the material being conveyed contains fractions of different weight, as soon as the material enters one of the separators, because they are cyclone separators, the heavy fraction will fall to the bottom and the lighter fraction will rise to the top. The lighter fraction will be drawn upwardly through the common suction pipe 42 and into the third separator 3. This third separator will again separate heavy and light fractions and the heavy fractions will fall through the base into the material collection vessel 4. The valve 43 is timed to open once every 30 minutes or at any other preset time interval so that material which has accumulated into the third separator 3 will fall into the material collection vessel 4. When the valve 43 is closed, valve 48 will be opened to atmosphere and eventually, when the vacuum has been relieved, the valve 49 will open and draw the heavy material through pipe 50 back into the upstream suction line 23 for further processing.

The lighter fraction from the third separator 3 will pass through pipe 44 and into the liquid ring pump 5.

Only a small amount of material will thus be passed and this small amount of material will be separated in the water separation tank 11 and finds its way into the sludge bottle 12. Because this small amount of material passes into the water circulation system of the liquid ring pump it can readily be separated out.

Claims (19)

1. A method of conveying flowable material from a first location to a second location, which includes drawing the material under suction, from the first location into a first container by opening a suction line to the first container, closing the suction line to the first container and opening the suction line to a second container to continue the drawing of material from the first location, and thereafter alternating the opening and closing of the suction line to the containers; on the suction line being closed to one said container, opening a pressure line to said container to pressurize the material therein and then opening a discharge valve of said container to convey the material under pressure through a discharge line to the second location; thereafter alternating the opening of the pressure line to said containers and opening the discharge valves to convey material under pressure to the second location; the suction input to the containers or the discharge from the containers being continuous.

2. The method of conveying flowable material as claimed in Claim 1, in which the containers are cyclone separators and, as material is drawn into the separators, the material is subjected to separation of the heavy a light fractions, the heavy fraction being discharged under pressure.

3. The method of conveying flowable material as claimed in Claim 2, in which the light fraction is fed to a third cyclone separator and subjected to further separation.

4. The method of conveying flowable material as claimed in Claim 3, in which the light fraction from the third separator is fed directly to a liquid ring pump and the heavy fraction from the third separator is fed to a material collection vessel, a valve between the third separator and the material collection vessel being controlled to open at spaced time intervals to draw material therein back to the suction line upstream of the first and second separators.

5. A method of conveying flowable material as claimed in Claim 4, in which air under presure of 100 psi is stored in a reservoir and released as necessary to the first and second separators.

6. The method of conveying flowable material as claimed in Claim 5, in which the air pressure in the reservoir is controlled not to fall below 40 psi to maintain valve operation.

7. The method of conveying flowable material as claimed in Claim 4, in which the liquid ring pump discharges water and air to a water separation tank having beneath it a sludge trap in which sludge is collected, separated water being fed to an air cooled radiator and thence to a header tank which feeds the pump with water.

8. A method of conveying flowable material substantially as herein described.

9. Apparatus for conveying flowable material from a first location to a second location, including two containers having a common inlet line and valves for controlling the flow of material to each container, a suction line common to both containers and valves for controlling the suction from each container, an outlet line common to both containers and valves for controlling the outlet from each container, and an air pressure line and valves for controlling the supply of air under pressure to each container.

10. Apparatus for conveying flowable material as claimd in Claim 9, in which the suction is provided by a liquid ring pump.

11. Apparatus for conveying flowable material as claimed in Claim 10, in which the liquid ring pump is driven by an internal combustion engine which also drives a compressor and a radiator fan.

12. Apparatus for conveying flowable material as claimed in any one of Claims 9 to 11, in which the containers are cyclone separators which receive the material tangentially and discharge the heavy fraction at the base and the light fraction at the top, the light fraction being drawn to a third cyclone separator for further extraction.

13. Apparatus for conveying flowable material as claimed in Claim 12, in which the base of the third separator is connected to a material collection vessel via a time controlled valve, the material collection vessel having a vent to atmosphere and having an outlet connected via a valve to the common inlet line to the other separators for recirculating the heavy fraction from the third separator.

14. Apparatus for conveying flowable material as claimed in either Claim 12 or Claim 13, in which the top of the third separator is connected to the liquid ring pump.

15. Apparatus for conveying flowable material as claimed in Claim 14, in which the connection between the third separator and the liquid ring pump incorporates a valve which opens the suction side of the pump to atmosphere when the first and second separators are full of material.

16. Apparatus for conveying flowable material as claimed in Claim 10, in which the liquid ring pump discharges into a water separation tank having a sludge bottle connected to the base thereof and a vent at the top for the escape of air, the said tank being connected to a fan cooled radiator and a header tank and thence to the pump.

17. Apparatus for conveying flowable material as claimed in any one of Claims 9 to 15, mounted on a chassis having wheels.

18. Apparatus for conveying flowable material as claimed in any one of Claims 9 to 17 in which all the valves are pneumatically operated.

19. Apparatus for conveying flowable material substantially as herein described with reference to the accompanying drawings.