GB2089310A

GB2089310A - Suction nozzle for pneumatically conveying bulk material

Info

Publication number: GB2089310A
Application number: GB8135575A
Authority: GB
Original assignee: Waeschle Maschinenfabrik GmbH
Current assignee: Waeschle Maschinenfabrik GmbH
Priority date: 1980-12-09
Filing date: 1981-11-25
Publication date: 1982-06-23
Also published as: SE8107244L; CH653647A5; AT386816B; ATA503081A; DE8032676U1; FR2495587A3; LU83816A1; DK543081A; JPS57111727U; BE891392A; JPS6040508Y2; IT8123484V0; FR2495587B3; NO814186L; NL8105287A; IT8123484U1; GB2089310B

Abstract

A suction nozzle for pneumatically conveying bulk material, which includes a feed pipe member (1) for extending into the bulk material via an open mouth (2) which is connected by a pipe portion to a primary suction air intake opening (5) for the conveying air. The opening (5) is disposed at a position on the member (1) which in use is outside the level of the bulk material, and the feed pipe member. (1) is provided above its maximum depth of immersion with a secondary suction air intake opening (3), the cross section of which is adjustable by means of a slide member (7). The feed pipe member (1) is divided into two flow paths by a partitioning wall (4) which extends parallel to or in line with the longitudinal axis of the pipe member and which extends from the mouth thereof to beyond the primary air intake opening (5), one of the flow paths connecting the primary air intake opening (5) to the mouth (2) of the feed pipe member and the other carrying the bulk material which is sucked in and communicating with the secondary air opening. <IMAGE>

Description

SPECIFICATION Suction nozzle for pneumatically conveying bulk material This invention relates to a suction nozzle for pneumatically conveying loose or bulk material, including a feed pipe member with an open mouth at one end for extension into bulk material, which mouth is connected by a pipe portion to a primary suction air intake opening for conveying air, with the primary opening being located on the pipe portion at a position which, in operation of the nozzle, is disposed outside the level of bulk material, and with the pipe member being provided at a position which in operation is above its maximum depth of engagement into the bulk material, with a secondary suction air intake opening, the cross-section of which is adjustable by means of a slide member.

A suction nozzle of this kind is known from DOS No. 25 23 1 55. In that arrangement, the tube portion which connects the mouth of the suction nozzle to the primary suction air intake opening which is above the level of bulk material comprises a jacket tube which is coaxial with respect to the feed pipe member and which, together with the feed pipe member, defines two annular gaps, of which the upper gap forms the air intake opening for the conveying air and the lower gap forms a flow transfer opening through which the conveying air flows into the mouth of the feed pipe member, thereby entraining the bulk material.

A disadvantage with that arrangement is the comparatively large amount of space occupied by and the amount of material used for the coaxial arrangement comprising the feed pipe member and the jacket tube which is disposed therearound.

There is thus a need for a generally improved suction nozzle, preferably one which saves space and material.

According to the present invention there is provided a suction nozzle for pneumatically conveying bulk material, including a feed pipe member with an open mouth at one end for extension into bulk material, whicn mouth is connected by a pipe portion to a primary suction air intake opening for conveying air, with the primary opening being located on the pipe portion at a position which, in operation of the nozzle, is disposed outside the level of bulk material, and with the pipe member being provided at a position which in operation is above its maximum depth of engagement into the bulk material, with a secondary sunction air intake opening, the cross-section of which is adjustable by means of a slide member, wherein the feed pipe member is divided into two flow paths (I, II) by a partitioning wall which extends parallel to or in line with the longitudinal axis of the pipe member and which extends from the region of the mouth of the pipe member to beyond the primary air intake opening, and by a transverse web portion, one (I) of the two flow paths connecting the primary air intake opening to the mouth and the other flow path (II) carrying bulk material which is sucked in and being in communication with the secondary air intake opening.

An embodiment of a suction nozzle according to the present invention is shown by way of example in diagrammatic simplified form in the accompanying drawings, in which: Figure 1 is a view in longitudinal section through a suction nozzle in operation, and Figure 2 is an end view and a side view of the suction nozzle shown in Fig. 1.

Referring to Fig. 1, a suction nozzle of the invention has a feed pipe member 1 which, in use, is passed preferably at an inclined angle through an opening which is formed in a suitable manner (not shown in detail herein) in a side wall of a loose or bulk material container 10. An open mouth 2 of the feed pipe member 1 extends into the bulk material S.

The other end of the feed pipe member 1 is connected to a conveyor conduit of a suction conveyor installation of any kind. Over the major part of its length, the feed pipe member 1 is subdivided into a flow path I and a flow path Il by a partitioning wall 4 which extends parallel to or in line with the longitudinal axis of the pipe member.Conveying air F is sucked in at a primary suction air intake opening 5 and flows by way of the flow path I to the mouth 2 of the pipe member and from there flows by way of the flow path II into the conveyor conduit which is connected to the suction nozzle, thereby entraining bulk material from the container 1 0. Together with the conveying air F, secondary air N is also sucked in at a secondary suction air intake opening 3 which is adjacent to but downstream of the primary air intake opening 5 and which is separated therefrom by a transverse web portion 6 between the pipe casing and the partitioning wall 4. Associated with the two openings 3 and 5 is a common slide member 7 which is displaceable parallel to the axis of the pipe member, in order to set optimum conveying conditions or a desired degree of entrainment of bulk material in the conveying air.

As can be seen in particular from Fig. 2, the slide member 7 operates on the differential principle, that is to say, the cross-sectional area of one opening 3, 5 which is exposed by the slide member increases in proportion to movement of the slide member in a direction such as to reduce the cross-section of the respective other opening.

Associated with each of the two openings 3 and 5 is a respective automatically operating non-return flap valve 8 and 9 respectively, made for example of a suitable resilient material. The non-return flap valves ensure that bulk material, in particular, bulk material in dust form, cannot escape from the openings 3 and 5 respectively, if for example the conveyor conduit which is connected to the suction nozzle is suddenly vented, that is to say, the reduced pressure therein is lost and possibly an increased pressure is built up for a short period of time.

Claims

1. A suction nozzle for pneumatically conveying bulk material, including a feed pipe member with an open mouth at one end for extension into bulk material, which mouth is connected by a pipe portion to a primary air intake opening for conveying air, with the primary opening being located on the pipe portion at a position which, in operation of the nozzle, is disposed outside the level of bulk material, and with the pipe member being provided at a position which in operation is above its maximum depth of engagement into the bulk material, with a secondary suction air intake opening, the cross-section of which is adjustable by means of a slide member, wherein the feed pipe member is divided into two flow paths (I, II) by a partitioning wall which extends parallel to or in line with the longitudinal axis of the pipe member and which extends from the region of the mouth of the pipe member to beyond the primary air intake opening, and by a transverse web portion, one (I) of the two flow paths connecting the primary air intake opening to the mouth and the other flow path (il) carrying bulk material which is sucked in and being in communication with the secondary air intake opening.

2. A suction nozzle according to claim 1, wherein the cross-section of the primary air intake opening and that of the secondary air intake opening are variable in opposition to each other by a common slide member which operates on a differential principle.

3. A suction nozzle according to claim 1 or claim 2, wherein the secondary air intake opening is arranged downstream of the primary air intake opening, in the direction of conveyance of the bulk material, and is separated from the primary air intake opening by the transverse web portion which connects a casing of the feed pipe member to the partitioning wall.

4. A suction nozzle according to any one of claims 1 to 3, wherein a respective automatically operable non-return flap valve is associated with each of the primary and secondary air intake openings.

5. A suction nozzle according to claim 4, wherein the non-return flap valves are arranged within the feed pipe member.

6. A suction nozzle for pneumatically conveying bulk material, substantially as hereinbefore described.