GB2038265A

GB2038265A - Suction collection devices and the collection of material by suction

Info

Publication number: GB2038265A
Application number: GB7937712A
Authority: GB
Original assignee: RENVAC Ltd
Current assignee: RENVAC Ltd
Priority date: 1978-10-31
Filing date: 1979-10-31
Publication date: 1980-07-23

Abstract

A suction collection device for material that shows a tendency to adhere to the suction conduit has a duct member (2) with an entry nozzle (4) at its forward end and a water inlet (12a) rearwards of the nozzle to admit a water flow that reduces the likelihood of blockage by adhered material. To maintain the suction flow when the entry nozzle may be buried deep in the material, a secondary air inlet (16a) to the duct can draw air from a point (16b) spaced rearwards remote from the nozzle. The device is employed in a vacuum collection apparatus in which a vacuum pump generating the suction flow draws the flow through separation means where the collected material is deposited from the flow. <IMAGE>

Description

SPECIFICATION Suction collection devices and the collection of material by suction This invention relates to suction collection devices and to vacuum collection apparatus using such devices.

Industrial vacuum collection apparatus is used for collecting particulate material, e.g. for the purpose of conveying and/or loading the material, and such apparatus has been designed for handling a wide range of particle sizes. The apparatus uses relatively large suction pressures and generally relies on inducing a high-rate airflow that has a fluidising action on the material to be able to convey large quantities of material at considerable speed.

However, the moisture content of the material is often found to be a critical factor for the efficiency of operation of the apparatus. Dry material can be quite easily entrained and near liquid mixtures, such as slurries, can also be handled easily by such equipment. But materials which are mixed with smaller amounts of liquid, such that they tend to be sticky or rather than wet, can cause considerable difficulties by tending to agglomerate as they are being drawn along with the airflow and to adhere to the sides of the conveying conduit.

A similar difficulty can arise if an attempt is made to collect fluid-like materials by suction, e.g. heavy oil deposits which may have a treacle-like consistency. Like sticky particulate materials these can easily block or substantially restrict the cross-section available for the flow.

According to one aspect of the present invention, there is provided a suction collection device comprising a suction duct member that is to be connected to a suction source, the forward end of the duct member providing an entry nozzleforthe material and a liquid supply means opening into said duct adjacent the entry nozzle for introducing liquid into the duct when the particulate material is being drawn in through said entry nozzle.

The entry nozzle can with advantage have a divergent cross-section, and preferably then the liquid supply means introduces liquid into the duct downstream or rearwards of said divergent crosssection. There may also be vent means for drawing a secondary airflow into the duct, preferably substantially in the region of the liquid supply means opening.

The liquid supply means may inject the water into the duct as a spray or as a trickle flow.

One particularform of suction collection device according to the invention is illustrated in the accompanying drawing, in which Figures 1 to 3 are side, plan and end views of the device respectively.

The drawings show a circular cross-section duct 2 having at its entry end a nozzle piece 4, the cross-section of which changes from square at its front end 4a to circular at its rear end 4b where it is welded to the entry end of the duct. The nozzle piece provides a cross-sectional area that gradually increases as it changes from square to a circular shape of substantially the same diameter as the duct. At its rear outlet end, the duct can be attached to a flexible pipe 6 for connection to a vacuum pump (not shown). Rigidly mounted on the duct is a water supply pipe 8, having at its rear end a connection fitting 10 for attachment to a flexible hose and its front end an elbow 12 leads to entry point 12a to the interior of the duct 2 immediately adjacent the rear of the nozzle piece 4.Near the rear end of the water supply pipe is a ballcock 14to control the flow through the pipe.

In use, an operator is able to manipulate the duct while the vacuum is applied through the flexible pipe, to bring the nozzle onto the material to be located, while at the same time admitting a flow of water of opening the ballcock. The divergent form of the nozzle piece 4 prevents jamming of the particulate material as it enters the duct entrained in the suction airflow, and further back the water acts as a lubricant, particularly between the material and the walls of the duct, to prevent the material sticking to and building up on the walls of the duct. In order to ensure that a flow of entrainment air is maintained even if the nozzle piece is deep into a pile of material, an entry air vent 16 is provided, opening into the duct at 16a immediately behind the nozzle piece and drawing in air from rearwardly spaced entry aperture 16b.

In the illustrated example, the duct 2 has an internal diameter of 7.6 cm. The nozzle section entry opening is 6 cm square and it is found that with these dimensions the device can handle particulate material of all sizes up to 5 cm.

The pipe 8 may receive its supply from the water main at normal mains pressure. The water may enter the duct in the form of a finely divided spray or a trickle flow. Although a single water inlet point into the duct is shown, it will be appreciated that two or more inlet points may be provided to distribute the water more uniformly at its entry, but preferably all the water inlets are under a common control. A large number of inlets could be provided by connecting the pipe 8 to a distributor ring running around the circumference of the duct.

The illustrated device forms part of a vacuum collection apparatus in use, of course, in which flexible pipe 6 is connected to a vacuum pump of said apparatus by suitable conduit means that in the passage of the flow to the pump lead the flow through a separation means where the collected material is deposited from the flow. Known forms of separation means can be employed and the choice in any particular apparatus will depend on the nature of the material. The means can for example comprise simple gravity separation means for larger particles, and/or cyclonic separators and/or electrostatic dust collectors for smaller particles.

1. A suction collection device comprising a suction duct member that is to be connected to a suction source, the forward end of the duct member providing an entry nozzle for the material and a liquid supply means opening into said duct adjacent the entry nozzle for introducing liquid

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Suction collection devices and the collection of material by suction This invention relates to suction collection devices and to vacuum collection apparatus using such devices. Industrial vacuum collection apparatus is used for collecting particulate material, e.g. for the purpose of conveying and/or loading the material, and such apparatus has been designed for handling a wide range of particle sizes. The apparatus uses relatively large suction pressures and generally relies on inducing a high-rate airflow that has a fluidising action on the material to be able to convey large quantities of material at considerable speed. However, the moisture content of the material is often found to be a critical factor for the efficiency of operation of the apparatus. Dry material can be quite easily entrained and near liquid mixtures, such as slurries, can also be handled easily by such equipment. But materials which are mixed with smaller amounts of liquid, such that they tend to be sticky or rather than wet, can cause considerable difficulties by tending to agglomerate as they are being drawn along with the airflow and to adhere to the sides of the conveying conduit. A similar difficulty can arise if an attempt is made to collect fluid-like materials by suction, e.g. heavy oil deposits which may have a treacle-like consistency. Like sticky particulate materials these can easily block or substantially restrict the cross-section available for the flow. According to one aspect of the present invention, there is provided a suction collection device comprising a suction duct member that is to be connected to a suction source, the forward end of the duct member providing an entry nozzleforthe material and a liquid supply means opening into said duct adjacent the entry nozzle for introducing liquid into the duct when the particulate material is being drawn in through said entry nozzle. The entry nozzle can with advantage have a divergent cross-section, and preferably then the liquid supply means introduces liquid into the duct downstream or rearwards of said divergent crosssection. There may also be vent means for drawing a secondary airflow into the duct, preferably substantially in the region of the liquid supply means opening. The liquid supply means may inject the water into the duct as a spray or as a trickle flow. One particularform of suction collection device according to the invention is illustrated in the accompanying drawing, in which Figures 1 to 3 are side, plan and end views of the device respectively. The drawings show a circular cross-section duct 2 having at its entry end a nozzle piece 4, the cross-section of which changes from square at its front end 4a to circular at its rear end 4b where it is welded to the entry end of the duct. The nozzle piece provides a cross-sectional area that gradually increases as it changes from square to a circular shape of substantially the same diameter as the duct. At its rear outlet end, the duct can be attached to a flexible pipe 6 for connection to a vacuum pump (not shown). Rigidly mounted on the duct is a water supply pipe 8, having at its rear end a connection fitting 10 for attachment to a flexible hose and its front end an elbow 12 leads to entry point 12a to the interior of the duct 2 immediately adjacent the rear of the nozzle piece 4.Near the rear end of the water supply pipe is a ballcock 14to control the flow through the pipe. In use, an operator is able to manipulate the duct while the vacuum is applied through the flexible pipe, to bring the nozzle onto the material to be located, while at the same time admitting a flow of water of opening the ballcock. The divergent form of the nozzle piece 4 prevents jamming of the particulate material as it enters the duct entrained in the suction airflow, and further back the water acts as a lubricant, particularly between the material and the walls of the duct, to prevent the material sticking to and building up on the walls of the duct. In order to ensure that a flow of entrainment air is maintained even if the nozzle piece is deep into a pile of material, an entry air vent 16 is provided, opening into the duct at 16a immediately behind the nozzle piece and drawing in air from rearwardly spaced entry aperture 16b. In the illustrated example, the duct 2 has an internal diameter of 7.6 cm. The nozzle section entry opening is 6 cm square and it is found that with these dimensions the device can handle particulate material of all sizes up to 5 cm. The pipe 8 may receive its supply from the water main at normal mains pressure. The water may enter the duct in the form of a finely divided spray or a trickle flow. Although a single water inlet point into the duct is shown, it will be appreciated that two or more inlet points may be provided to distribute the water more uniformly at its entry, but preferably all the water inlets are under a common control. A large number of inlets could be provided by connecting the pipe 8 to a distributor ring running around the circumference of the duct. The illustrated device forms part of a vacuum collection apparatus in use, of course, in which flexible pipe 6 is connected to a vacuum pump of said apparatus by suitable conduit means that in the passage of the flow to the pump lead the flow through a separation means where the collected material is deposited from the flow. Known forms of separation means can be employed and the choice in any particular apparatus will depend on the nature of the material. The means can for example comprise simple gravity separation means for larger particles, and/or cyclonic separators and/or electrostatic dust collectors for smaller particles. CLAIMS

1. A suction collection device comprising a suction duct member that is to be connected to a suction source, the forward end of the duct member providing an entry nozzle for the material and a liquid supply means opening into said duct adjacent the entry nozzle for introducing liquid into the duct when the particulate material is drawn in through said entry nozzle.

2. A device according to claim 1 wherein the entry nozzle has a rearwardly divergent form.

3. A device according to claim 2 wherein the liquid supply means is arranged to introduce liquid into the duct rearwardly of said divergent crosssection.

4. A device according to any one of claims 1 to 3 having an opening spaced rearwardly of the forward end of the duct member for the admission of a secondary airflow into the duct member.

5. A device according to claim 4 wherein an inlet extending passage extends rearwardly along the duct from said opening to draw in air from a position remote from said forward end.

6. A device according to claim 4 or claim 5 wherein said secondary air flow opening is positioned longitudinally of the duct substantially in the region of the liquid supply means opening.

7. A device according to any one of the preceding claims wherein said liquid supply means opens into the duct at more than one position circumferen tially thereof.

8. A device according to claim 7 wherein the liquid supply means opens into the duct through a distributor ring.

9. A method of collecting material of a sticky or adherent by suction through a duct member, wherein a flow of liquid is introduced into the duct member rearwards of the forward entry end for the material in order to reduce any tendency of the material to accumulate on the internal walls of the duct member.

10. A suction collection device constructed and arranged for use and operation substantially as described herein with reference to the accompanying drawing.

11. A vacuum collection apparatus comprising a suction collection device according to any one of claims 1 to 8 or 10.

12. A method of collecting a sticky or adherent material substantially as described herein.