JP2796324B2 - Granular material mixing device and pressurized gaseous fluid circulation device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus and a system for supplying a pressurized gaseous fluid to a container containing a material. In particular, the invention relates to an apparatus for supplying a pressurized gaseous fluid to an apparatus for mixing particulate materials.

B. Prior art Prior to the present invention, mixing devices for particulate materials, such as plastic pellets, are already known. A mixing device of the type to which the present invention relates has a container with a vertically oriented lift tube mounted at its center, the lift tube serving as a means for circulating the material at the bottom of the container to the top of the container. Have been to be. This function is achieved by supplying a gaseous fluid or air under pressure into the bottom of the container and conducting it upward through said vertical lift tube.
This pressurized air entrains the material in the bottom of the container, transports it upward through the lift tube and discharges said material from the lift tube in the form of a geyser into the top of the container, thus allowing the material to pass through the container. Circulated. Performing such circulation of the material through the lift tube requires the use of a given gas velocity at a given pressure. But,
During the start phase of the material mixing, the container contains some resting material and the lift tube is partially full of material. In order to initiate the circulation of the material through the lift tube and thus the mixing of the material, a stationary head or pressure of the material remaining clogging inside said lift tube and / or inside the container surrounding the inlet of the lift tube. It is necessary to overcome

To provide the required pressure, the pressurized gas supply system typically ranges from about 0.28-0.42 Kg / cm ² (4-6 psi) at gas velocities on the order of about 750-1050 m / min (2500 ft-3500 ft). It has a rotary positive displacement blower or other medium pressure gas supply that supplies pressurized gas. This pressure is higher than required during steady-state operation of the pressurized gas supply system after startup. During steady state operation, pressurized gas in the range of 0.10 Kg / cm ² -0.170 Kg / cm ² (1.5-2.5 psi) is required. Such pressures and demands may be provided by low pressure centrifugal blowers or high pressure fans.

C. SUMMARY OF THE INVENTION Initial equipment costs and maintenance requirements for centrifugal blowers or high pressure fans are lower than for rotary displacement blowers. In the case of a centrifugal blower, the motor does not become overloaded when the exhaust air flow rate is reduced to zero, and does not require a safety release valve in such situations. Furthermore, centrifugal blowers or high-pressure fans are significantly quieter than rotary displacement blowers, so that no muffler is required during operation. For these reasons, it is desirable to be able to use a centrifugal blower or a high pressure fan rather than a rotary displacement blower in a mixing device for particulate materials, but there are some drawbacks. Unfortunately, the basic performance characteristics of centrifugal blowers or high pressure fans lack the high pressure surge capability to break through the initial pressure in the vessel, for example, during start-up or during restart of the mixing device.

Accordingly, it is a primary object of the present invention to provide a low cost system for supplying pressurized gaseous fluid to a container for a material, particularly containing particulate material.

Another object of the present invention is a system for supplying pressurized gaseous fluid to a container for particulate material, the centrifugal blower or high pressure fan as a source of pressurized gaseous fluid for start-up and continuous operation. Is to provide something that can be used.

D. Means and actions for achieving the object In general, these and other objects are to provide a device for mixing particulate material, a vertically oriented container having a centrally mounted vertical lift tube. A lift tube having a material inlet proximate the bottom of the container and a material outlet proximate the top of the container, wherein the container has an inlet for a gaseous fluid adjacent the bottom, whereby the pressurized gaseous fluid Wherein the material is fed to the bottom of the container to entrain the material in the container, transport the material from the inlet of the lift tube through a vertical lift tube to its outlet, and discharge the material into the top of the container. The first of the gaseous fluids that can supply a gaseous fluid at a pressure sufficient to circulate the gas in the vessel but insufficient to break up the initial pressure of the material in the vessel encountered at the start-up of the apparatus. A supply source and the first supply source Conduit means in flow communication with the inlet for the bodily fluid; and gaseous fluid in flow communication with the conduit means for pressurizing the conduit means to a pressure sufficient to disrupt the initial pressure of the material in the vessel. A second source;
Control means for regulating the supply of gaseous fluid from the first source and the second source to the conduit means and from the conduit means to the inlet for the gaseous fluid in the container. This is achieved by providing

In accordance with the present invention, the gaseous fluid supply conduit serves as a miniature receiver or receiver that is pressurized prior to startup. This pressurization is performed by pressurizing the conduit by the action of a centrifugal blower or fan to a first pressure which is the maximum capacity of the blower or fan, ie, to zero flow capacity of the blower or fan. You. In addition, the conduit is connected to a second source of pressurized gas, such as plant air, which constantly has a pressurization capacity of 7.0 kg / cm ² (100 psig). The plant air is used to pressurize the gas supply conduit until the initial head or pressure in the remaining portion of the material is broken down to a suitable pressure to initiate circulation of the material. When the conduit is pressurized to a desired pressure,
The main air supply valve for the container is opened to allow a burst of high pressure in the conduit, thereby breaking down the pressure of the material in the container and allowing the mixing operation to commence. Continuous mixing is maintained by a continuous supply of a first lower pressure gaseous fluid in a centrifugal blower or fan. Appropriate controls are provided to control the pressurization of the conduit and the release of pressure from the conduit to the mixing vessel.

The present invention will now be described in connection with the accompanying drawings.

E. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention is particularly directed to use in connection with a mixing device for particulate material, which is desirous of supplying a pressurized gas to a container containing the particulate material and relieving the pressure of the material. It should be understood that it is also useful in other applications where it is required to do so. The present invention is also required to supply pressurized gas to containers that are required to overcome the initial back pressure, while in other applications where continuous operation can be performed at relatively low pressures. Useful.

The present invention is described below as applied to a mixing device generally designated 1. This mixing device 1 is 1
It has a single upstanding container 2, which has a suitable inlet for the pellets of the material to be mixed, for example plastic, in its bottom or in its top.
The disclosed container 2 has a vertically oriented and centrally mounted lift tube 5, which has a lower material inlet 6 and an upper material outlet 7. A distribution cone 8 is mounted above the upper material outlet 7. A plurality of circumferentially spaced downcomers 9 each having a vertically spaced material inlet 10 are provided inside the container. The material is supplied from the upper part of the container so as to enter the downcomer 9 through the material inlet 10 and to be discharged through the outlet 3 into the lower section 11 of the container 2. Pressurized gas is supplied to the bottom of the container 2 through an inlet 15 for pressurized gaseous fluid. The gaseous fluid entrains the material present in the lower section 11 of the container 2 and conveys it upward through said lift tube 5 and is discharged in a manner similar to a geyser into the top of the container 2 through the upper material outlet 7. So as to be introduced into the lower material inlet 6 of the lift tube 5. Such a circulation of material from the upper section through the downcomer 9 to the lower section 11 and from the lower section 11 to the top of the container 2 causes a circulation or mixing of the material present in the container 2. A vent 12 is provided for discharging the used mixing gas from the container 2.

The mixing device 1 itself and its operation are described in U.S. Pat. No. 4,569,596, issued Feb. 11, 1986, and U.S. Patent Application No. 06/848005, filed Apr. 3, 1986, and are hereby incorporated by reference. It need not be described in further detail.

Said inlet 15 for the pressurized gas is connected to a conduit 16 which serves as a supply conduit for the pressurized gas from a gas supply and control device to be described later and for the mixed particulate material. Work as an exit. For the latter operation, the conduit 16 is connected to a material recovery line 17. A main air valve 18 and a material outlet valve 19 are located in conduit 16. During operation, when the material is being mixed, the material outlet valve 19 is closed and the air valve 18 is open. When it is desired to recover material from the container 2, both the air valve 18 and the material outlet valve 19 are opened.

The system for supplying pressurized gaseous fluid is generally designated by 25 and has a first source 26 of gaseous fluid having a first pressure. This source 26 typically has 0.210 kg /
It is in the form of a high-pressure fan or a centrifugal blower capable of supplying air cm ² (3psi). The system 25 also has a second source 28 of gaseous fluid. Source 28 has a second pressure that is higher than the first pressure and is up to 7.030 kg / cm ² (100 psi).
g) may be available plant air capable of supplying pressurized air. This high pressure source is also used for other applications in the installation in which the mixing device is located, thus providing a separate capital cost allocation for the mixing device, except for some connection valves and the control device contemplated by the present invention. do not need. Each of the pressurized gas sources 26, 28 is connected to a conduit 29 for supplying a pressurized gaseous fluid to the conduit 16 and the inlet 15 for the pressurized gas in the container 2.

The present invention provides a control, generally designated 30, for controlling the supply of gaseous fluid from a first supply 26 and a second supply 28 to conduit 29 and from conduit 29 to inlet 15 for gaseous fluid. With device. This control device 30 is
It has a first pressure responsive valve 32 for controlling the flow rate of gas sent to the container 2 through 15. This valve 32 is set to open when the pressure in conduit 29 exceeds a predetermined maximum pressure. The maximum pressure is 0.420 Kg / cm ² (6 psig), a level slightly higher than that required to start the initial operation of the mixing apparatus and to break up the initial pressure of the material. The control device 30
Also has a pressure relief valve 34 connected to the conduit 29 to relieve pressure in the conduit 29 if a predetermined safety pressure higher than the pressure is exceeded. The valve 34 is not shown as a component required for the operation of the present invention, but as one typically used for good design practice.

Further, the controller 30 connects the second source 28 to the conduit to control the flow rate of gas flowing from the second source 28 to the conduit 29.
It has a second valve 36 located in a conduit 40 in flow communication with 29. Valve 36 is an on / off (two-way) solenoid valve. Valve 36 is adapted to be closed when the mixing device is not starting. The controller 30 also has a third valve 38 for adjusting the pressure of the gas supplied to the conduit 29 by the second supply 28. A non-return valve 39 is located between the first low pressure source 29 and the conduit 29 so that when high pressure is present in the conduit 29 it does not flow back through the source 26.

During operation, when the container 2 is filled with materials, the container 2
There is a material pressure in the lower section 11 and also inside the lift tube 5. Thus in order to initiate the lifting and circulating upwardly through the lift tube 5 material by crushing pressure of such materials, specific gas pressure for example 0.420Kg / cm ² (6psig) it is required. This pressure is higher during steady-state operation. In the present invention, conduit 29 may serve as a reservoir or receiver for high pressure air. Conduit 29 is pressurized by using a combination of a source 26 of low pressure air and a source 28 of high pressure air until a pressure sufficient to break the pressure of the material is reached.
With the main air valve 18 and the material outlet valve 19 closed, the first supply 26, a centrifugal blower or high pressure fan, is started. The source 26 immediately pressurizes the conduit 29 to a pressure corresponding to the zero flow pressure capability of the source 26. At the same time, source 28 is turned on and valve 36 is opened to allow a small amount of high pressure air from source 28 to pressurize conduits 40 and 29. This pressure is regulated by a valve 38 or pressure regulating valve, thereby setting the desired predetermined pressure. If the mixing device 1 and the first source 26 or centrifugal blower are connected in close proximity to one another,
It should be noted that if is short, it is necessary to provide a small receiver in the conduit 29 to provide a suitable amount of gas at a higher pressure. Said pressure relief valve 34 functions as a pressure safety switch to guarantee a maximum pressure in the conduit 29 in the event of a valve 38 failure.

The first pressure response valve 32, that is, the pressure switch, is set to a predetermined maximum pressure. As soon as the pressure in the conduit 29 has reached its predetermined pressure, the second valve 36 is closed, so that no additional air is supplied to the conduit 20 from the second supply 28. When it is desired to start pressurized gaseous fluid supply system 25, main air valve 18 and first pressure responsive valve 32 are simultaneously opened. At this moment, the pressurized air trapped in the conduit 29 between the check valve 39 and the inlet 15 rushes into the mixing device 1 and is directed upwards through the lift pipe 5 and during the previous shutdown As a result, the residual particulate material stagnated in the lift pipe 5 is carried away.

When the pressure in conduit 29 drops below the zero flow pressure of first source 26, check valve 39 causes source 26 to enter inlet 15 through conduit 29 to perform a continuous mixing operation at the low pressure capacity of source 26. It allows the supply of pressurized gas to be continued.

When it is desired to transfer the mixed material from the container 2, the air supply through said conduit 29 is shut off and the main air valve 18 and the material outlet valve 19 are opened, whereby
Material can be discharged through the outlet of the material recovery line 17.

The particular valves used in connection with the present invention are well known and those skilled in the art will be able to properly select the correct size and capacity valve according to the particular application.

From the above description, it can be understood that the objects of the present invention have been achieved. A system was provided to supply a short burst of high pressure air to the mixing device to crush the pressure of residual material stagnating in the vessel. However, this system utilizes low equipment cost centrifugal blowers or fans for continuous operation.

While the above describes one preferred embodiment of the present invention, it is intended that the invention be limited only by the subject matter of the appended claims.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a mixing device for a granular material, and FIG. 2 is a schematic diagram of a control device of the present invention. In the drawing, 1 ... mixing device, 2 ... container, 3 ... outlet, 5
… Lift tube, 6… Lower material inlet, 7… Upper material outlet,
15 ... inlet, 17 ... material recovery line, 18 ... main air valve, 25
... pressurized gaseous fluid supply system, 26 ... first supply source, 28 ...
... a second supply source, 29 ... a conduit, 30 ... a controller, 32 ... a first pressure responsive valve, 34 ... a pressure relief valve, 36 ... a second valve, 38 ... a third valve, 39 ... check valve, 40 ... conduit.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁶ , DB name) B01F 13/02 B29B 7/00-7/94 WPI (DIALOG)

Claims (6)

(57) [Claims] 1. An apparatus for mixing particulate material, comprising a vertically oriented container having a vertically mounted vertical lift tube, the lift tube being adjacent to a bottom of the container and a material inlet and a container. A material outlet adjacent the top, wherein the container has an inlet for a gaseous fluid adjacent the bottom, whereby pressurized gaseous fluid is supplied to the bottom of the container to entrain the material in the container. An apparatus for transporting said material through said vertical lift tube from said inlet to said outlet of said lift tube and discharging it into the top of a container, comprising a gaseous fluid supply system, said gaseous fluid supply system comprising: Gaseous fluid that can supply a gaseous fluid at a pressure sufficient to circulate the material in the vessel through the vessel, but insufficient to break up the initial pressure of the material in the vessel encountered at the start of the apparatus. A first source and the first source Conduit means in flow communication with the inlet for the gaseous fluid of the vessel, and flow communication with the conduit means for pressurizing the conduit means to a pressure sufficient to disrupt the initial pressure of the material in the vessel; And a supply of gaseous fluid from the first and second sources to the conduit means and from the conduit means to an inlet for the gaseous fluid in the container. An apparatus for mixing particulate material, comprising: control means for adjusting the particle size. 2. The apparatus of claim 1 wherein said control means is mounted between first and second sources of said pressurized gaseous fluid and an inlet for said gaseous fluid. A first pressure responsive valve for limiting the supply of gaseous fluid from the means to an inlet for the gaseous fluid; and a second pressure supply valve disposed between the second source of pressurized gaseous fluid and the conduit means. Apparatus for mixing particulate material having a second valve for controlling the flow of pressurized gaseous fluid from said second source to said conduit means. 3. The apparatus of claim 2 wherein said control means is located between a second source of said gaseous fluid and said conduit means and is supplied to said conduit means by said second source. A third valve for adjusting the pressure of the gaseous fluid to mix the particulate material. 4. The apparatus of claim 3 further comprising a main air valve between said conduit means and an inlet for said gaseous fluid, said second source of said gaseous fluid being provided by said conduit. An apparatus for mixing particulate material, wherein the main air valve is closed when used to pressurize the means. 5. The apparatus for mixing particulate materials according to claim 4, further comprising a check valve located between said first source of gaseous fluid and said conduit means. 6. The apparatus of claim 4, wherein said second valve is closed when the pressure in said conduit means reaches a predetermined maximum pressure, and said first response valve and said main valve are closed. A device for mixing particulate material, wherein the air valve is adapted to open simultaneously upon start-up of the device after reaching said predetermined maximum pressure.