|Title of Invention||
"A PIPE CLEANING SYSTEM FOR CONVEYOR LINES"
|Abstract||A pipe cleaning system for conveyor lines with a feed station (4), which includes a component, particularly a slide valve, which is movable by an external power drive (5), with a chamber (4k) for inserting a cleaning body (11), with a chamber (4k) is situated, in a first position, outside a conveyor line (2, 3) and is movable into a second position with the aid of the external power drive in order to introduce the cleaning body (11) inserted into it into the conveyor (2,3) wherein means (6, 8, 10) are provided for securing the movable component against being moved by the external power drive during the insertion and/or the removal of the cleaning body (11), characterized in that the securing means include at least one switching element (8), which detects the insertion or removal process, and at least one switching means (10), which is actuable by the latter and, in the event of a condition or signal from the at least one switching element (8) representing an insertion/removal process, prevents movement of the chamber (4k) by the external power drive. Fig. 2|
|Full Text|| The present invention relates to a pipe cleaning system for conveyor lines
Sludge pumps have been used to convey concrete, in particular, for a long time. As a rule, they are configured as hydraulically operated piston pumps, usually twin-cylinder pumps, which convey the concrete through hoses or pipes. In the following, for the sake of simplic¬ity, reference will always be to concrete conveyance. However, the invention is not re¬stricted to use with concrete pumps, but may be used for all similar pipe-cleaning systems involving sludge pumps.
A special version of these concrete pumps is mounted on trucks fitted with a boom or the like. Concrete pumps of this kind are of particular interest in connection with the invention, since with these pumps, there is the problem that on completion of a pumping, i.e., convey¬ing operation, residual concrete in the delivery lines must be blown out therefrom with the boom extended, thus clearing the lines for the next pour. Depending on the position, length and height of the boom and delivery lines, pump discharge pressures of upto 10 bar are' encountered.
It is known (DE-A1-29 27 324) that for this purpose, a wiping or cleaning element can be introduced into the delivery line, this element being so dimensioned that it essentially fills out the cross-section of the delivery line and may be driven by fluid pressure (especially air pressure) through the entire length of the delivery line. As it moves through the line, it pushes the sludge in front of it. In most cases, a ball-shaped cleaning element of relatively soft material (e.g. rubber) is used, which makes a good seal with the pipeline walls. In the following, the cleaning element will thus always be referred to as a ball, without thereby precluding other shapes and materials.
To introduce the ball into delivery line engineered to withstand relatively high pressures, the line must be temporarily opened. A preferred embodiment of a device for introducing the ball into the delivery line consists in an importation station installed permanently in the de-livery line, directly at the pump outlet. The importation station is engineered preferably as a hydraulically operated dual-chamber slide. During normal pump operation, one slide cham-ber is located in the delivery line, i.e. it forms a short section of the delivery line itself. The other slide chamber, by contrast, is located outside the delivery line in a loading position, and the ball can be inserted into it by hand.
To clean out residual sludge/concrete from the delivery line, the slide chamber containing the ball is moved by external force into the position of the first chamber. This operation re-quires a considerable amount of force, as gravity may be causing the column of sludge in the delivery line to press on the side walls of the slide. The slide is preferably moved back and forth with the help of a hydraulically operated differential cylinder, but other reversible drives, e.g. electric drives, are also possible. As a result, the ball is moved into the delivery line, while the first chamber is now located outside the delivery line, where it may, if neces-sary, be emptied and cleaned. A small section of the line still filled with the hitherto con-veyed sludge is thus replaced by a sludge-free section containing only the ball for clearing the delivery line.
During the customary manual insertion of the ball there is a certain risk of the slide's exter-nal drive being switched on unintentionally. If this happens despite all the safety informa-tion that is naturally contained in the operating manual, the hand of the person inserting the ball is endangered. To ensure that the line is leakproof irrespective of which line section of the slide is operative at any one moment, firm sealing edges have to be provided, along which the slide is guided.
It is known (SCHWING GmbH's operator's manual for Item No. 101 98 516), that acci-dents of this kind can be prevented by providing a safety detent with mechanically/manually operated slides in the hydraulic installation. However, operator errors can not be ruled out with this system, either.
It would also be conceivable to configure the insertion opening in such manner as to prevent one from reaching into the endangered zone with one's hand, for example, by attaching an adequately long pipe to the opening, through which the ball can roll in by itself or be forced in by an additional device. However, an arrangement of such kind would make it difficult to remove the ball and would unsuitably enlarge the necessary compact design.
The problem addressed by the invention is thus to develop a pipe-cleaning system of like kind and including a safety device in such manner that danger to the operator while inserting the cleaning element can be practically be ruled out.
This problem is solved according to the invention with the features of claim 1. The features of the subclaims represent useful developments of the invention.
In implementing the invention it must be remembered that sludge purnps, especially con-crete pumps, have to withstand extremely harsh service conditions with a high degree of soiling, and that operating instructions and safety regulations may not always be observed. All safety devices must therefore be sturdy and reliable and must, if necessary, be of redun-dant design.
It would by all means be conceivable, for example, to provide a light barrier or other di-rectly acting sensors (infrared, ultrasonic) in the ball insertion area, which detect every ob-ject that comes into the vicinity of the slide or the monitored openings. In the event of a de-tection signal from the sensor, operation of the importation station's external drive will be directly or indirectly interrupted. To this end, electrically/electromagnetically switched safety valves, for example, may be installed especially for this purpose in the hydraulic or pneumatic circuit of the actuating cylinder, or else existing valves of such kind may be de-activated in a suitable manner. Of course, it is preferable to configure a shut-off or safety valve of this kind in such manner that it is normally closed and prevents the supply of pres-sure medium to the actuating cylinder, that is, to the insertion-station drive. The shut-off valve may be configured to act directly or indirectly, i.e. it may be connected into an exist-
ing actuating-cylinder feed circuit or it may be configured as a control valve that actuates a main valve.
An electric drive may be deactivated even more easily by cutting off its power supply if the safety device reacts. Here too, directly or indirectly acting switching means (relay, elec-tronic) may be provided.
With sensor arrangements of this kind, however, which are relatively delicate, a certain risk of damage and/or impaired functioning under harsh construction-site conditions can not be permanently ruled out.
Accordingly, in a preferred embodiment - to be explained in even more detail - of the in-vention, the importation station is provided with at least one movable closure member whose position is mechanically detected by means of at least one switching element. The closure member is preferably mounted such that it can and must be opened manually in or-der to insert the ball into the importation station, and must be closed after the ball has been inserted.
The closure member is preferably configured as a pivotable or slidable shutter that closes off the ball-insertion opening completely or at least far enough to prevent a foreign body from getting through the opening when the shutter is in the closed position. However, it would also be conceivable to provide a removable shutter.
If this closure member is in an even partly open position, the switching element responds and prevents operation of the external drive.
The switching element may be a switch, a sensor or also a valve. It changes its state de-pending on the position of the closure member, i.e. a sensor or switch will generate a signal, or a valve acting as switching element will be closed or opened. The switching element and
the switching means may thus be one and the same thing, since a valve, as a perfect exam-ple, may both detect a certain position and, in this position, influence the operation of the external drive.
The switching element may also be provided on a device for locking the closure member, so that it will respond even if the closure member has merely been unlocked and there is ac-cordingly a possibility of its being moved from the closed into the open position.
In a useful development of the pipe-cleaning system according to the invention, not only the opening for inserting or removing the ball is monitored but, if necessary, also the area into which, once the ball has been inserted, the other chamber of the importation station is moved. The same risk of injury, namely, will always exist there if this chamber is moved into a space which, for example, is not completely enclosed by a protective cover. It may be to advantage, for example, if a protective cover of this kind is not of completely closed de-sign, thus permitting easy cleaning of the line section moved into it.
Here, a safety device according to the invention can prevent body parts from being squashed between the outer wall of the outwardly-moving pipe chamber and the aforementioned pro-tective cover; during cleaning work, it will also prevent any actuation or reversal of the drive for returning the importation station to the other position.
This area can likewise be provided, for example, with a movable closure member whose closure state is monitored directly or indirectly by a switching element. If this switching element signalizes that the closure member is open or has been removed, the external drive is deactivated or blocked.
It goes without saying that the system according to the invention can be used not only for importation stations with linear-motion components, but also for stations with rotary-motion components, for example.
It is also possible to advantageously combine several of the safety elements discussed above in order to form a redundant system if required. For example, even if a closure member has been fitted, it is possible to additionally provide a sensor for the contact-free detection of an object or body part in the danger zone.
Further details and advantages of the subject of the invention are apparent from the simpli-fied drawings of an embodiment and the subsequent detailed description thereof that fol-lows.
Fig. 1 shows a first perspective view of an importation station for a pipe-cleaning system according to the invention, with the closure shutter closed;
Fig. 2 shows a second view similar to that of Fig. 1, with the closure shutter open;
Fig. 3 shows a detailed view of the closure shutter of Fig. 1 and of its safety mechanism;
Fig. 4 shows another detailed view after the closure shutter has been unlocked;
Fig. 5 shows a detailed view of the open closure shutter of Fig. 2, with the operation of the insertion-station drive being actively prevented.
As shown in Fig. 1, an importation station 1 installed downstream of a sludge pump that is not shown comprises a reducer bend 2 on the inlet side (between the pump and the importa-tion station 1), a pipe bend 3 on the outlet side (to which the delivery line to be cleaned -not shown here connects) and a slide casing 4 that has a hydraulic actuating cylinder 5 at the drive end and a closure shutter 6. The latter is mounted on the slide casing 4 such that it is pivotable about an axis A, and is shown here in the closed position.
Above the closure shutter 6 a pivoted safety lever 8 is also visible, which in turn acts di-rectly on a valve 10. The latter forms a switching element for detecting an open position of the closure shutter 6. When the safety lever 8 is in the locking position as shown, the valve is open and permits the supply of pressure medium to the actuating cylinder 5 (operative position).
Fig. 2 shows the same view as Fig. 1, here with the closure shutter 6 open. Behind it, the pipe-shaped chamber 4K is visible, into which a ball 11 may be inserted, which, after the closure shutter 6 has been closed and the chamber 4K moved into position between the pipe elbows 2 and 3, may be pushed through the delivery line by a pressure medium in order to blow out the line and clean it. It is also evident from Fig. 2 that the safety lever 8 has been swung upwards to release the closure shutter 6. The switching element, or the valve 10, is now closed and interrupts the supply of pressure medium to the actuating cylinder 5. The swung-up position of the safety lever 8 creates a state that represents the insertion or re-moval process.
At the opposite end of the importation station to the actuating cylinder 5 - in the drawing at the bottom right - a closed space is visible into which, when the chamber 4K is slid into the delivery line, the chamber or line section that is normally in the delivery line is transferred.
In a manner not shown, a closure member to be provided for this space - like the closure shutter 6 for the importation station 4 - could be monitored by means of a switching ele-ment in order to largely rule out the risk of injury in this area, too.
Fig. 3 is a detail showing a possible arrangement of the closure shutter 6, the safety lever 8 and the switching valve 10. The axis A of the closure shutter 6 is again evident. A gate ele-ment 7 is permanently mounted on the shutter side facing the safety lever 8. The gate ele-ment is of roughly triangular outline, with the side of the triangle facing away from the axis A of the shutter closure 6 being convex.
The gate element 7 is in the same plane as a sickle-shaped disk 9 mounted on the safety lever 8. The disk 9 is essentially circular, with a segment cut out of it. The centre point of the sickle-shaped disk 9 coincides with the pivoting axis of the safety lever 8. The cutting line of the segment cut out of the circular disk is slightly concave. It has approximately the same radius of curvature as the convex side of the triangular gate element 7.
In Fig. 3 it is evident that the gate element 7 would run up against the sickle-shaped disk 9 if the closure shutter 6 were to be swung up around its axis A. The closure shutter 6 is thus safely locked in this position by mechanical means, and no access to the chamber 4K is pos-sible. Even if the safety lever were to be raised slightly, the locked condition of the closure shutter 6 would not change.
Figures 4 and 5 show, in a similar way to Fig. 2, the safety lever 8 after it has been swung up anti-clockwise by about 90° out of the locking position. It is evident that the curvature of the convex side of the of the gate element 7 continues in the concave line along which the segment was cut out of the sickle-shaped disk 9. Only when the safety lever 8 is in this posi-tion, in which the valve 10 is closed, can the closure shutter 6 be raised.
When the shutter is raised, the convex side of the triangular gate element 7 slides along the concave cutting line of the segment cut out of the sickle-shaped disk 9, as can be seen in Fig. 5, which also shows the final position reached by the closure shutter 6 when it is swung upwards. The convex side of the triangular gate element abuts against the concave cut side of the sickle-shaped disk 9 such that the safety lever 8 is prevented from turning for as long as the closure shutter 6 is in the swung-up position. In consequence, the valve 10 can not be opened again while the closure shutter 6 is open, thus preventing any operation of the actu-ating cylinder 5.
The closure shutter 6 may be pivoted in such manner that it closes automatically under the influence of gravity when let go. To insert the ball, the user must hold the closure shutter 6 open with one hand and insert the ball with the other.
However, an arrangement is also possible whereby the closure shutter 6 engages in the raised position and requires slight pressure to push it down into the closed position.
Instead of the closure shutter 6 being pivotable about the axis of rotation A, which, as shown here, is horizontal in the fitting position, other configurations are also possible; pro-vision may be made, for example, for a closure shutter to be pivotable about a vertical axis, or to be pushed in a straight line or along an arc. It would also be possible to provide a re-movable closure shutter. Which variant will ultimately be implemented will depend primar-ily on the amount of space available for moving parts under the respective installation con-straints.
Further, in place of the purely mechanical sensing - as shown here - of the closure and locked position of the closure shutter 6 by means of the safety lever 8 and the valve 10, elec-tromechanical, electrical or electronic variants are conceivable, too, as already mentioned at the beginning.
For example, if the operation of the actuating cylinder 5 is controlled by means of electri-cally switchable valves that are closed when the cylinder is in the inoperative position, the power supply to these valves can be interrupted by way of an electric switching element that monitors the position of the closure shutter 6 or of the safety lever 8. In consequence, no pressure medium can reach the cylinder for as long the closure shutter 6 is open or the safety lever 8 raised.
1. A pipe cleaning system for conveyor lines with a feed station (4), which includes a component, particularly a slide valve, which is movable by an external power drive (5), with a chamber (4k) for inserting a cleaning body (11), with a chamber (4k) is situated, in a first position, outside a conveyor line (2, 3) and is movable into a second position with the aid of the external power drive in order to introduce the cleaning body (11) inserted into it into the conveyor (2,3) wherein means (6, 8, 10) are provided for securing the movable component against being moved by the external power drive during the insertion and/or the removal of the cleaning body (11), characterized in that the securing means have at least one switching element (8), which detects the insertion or removal process, and at least one switching means (10), which is actuable by the said insertion or removal process and in the event of a condition or signal from the at least one switching element (8) representing an insertion/removal process, prevents movement of the chamber (4k) by the external power drive.
2. A pipe cleaning system as claimed in claim 1, wherein the switching element is constituted by at least one sensor for detecting the presence of an article in the vicinity of the insertion opening.
3. A pipe cleaning system as claimed in claim 1 or 2, wherein the securing means includes at least one movable valve member (6), which is movable away from a rest position for the insertion or removal of the cleaning body (11) and that at least one switching element (10) is provided for detecting a position of the valve member (6) differing from the rest position and, in this position, prevents activation of the external power drive (5).
4. A pipe cleaning system as claimed in claim 1, 2 or 3, wherein the valve member (6) is constructed as a cover or flap closing the insertion or removal opening for the cleaning body (11).
5. A pipe cleaning system as claimed in claim 3 or 4, wherein at least one securing element (8) is provided for locking the valve member (6) in its closed position and that at least one switching element (10) is provided for detecting the position of the securing element (8), which, in a released position of the securing element (8), prevents activation of the external power drive.
6. A pipe cleaning system as claimed in one of the preceding claims, wherein the securing means also includes at least one switching element (10) for monitoring an entry region, into which the movable portion of the feed station moves when moving into its second position, wherein the said switching element (10) directly or indirectly prevents operation of the external power drive, when an object is detected in the entry region; and/or a valve member (6) closing access to the entry region is not situated in the closed position; and/or a securing member provided for securing the valve member closing the access to the entry region is situated in a released position.
7. A pipe cleaning system as claimed in one of the preceding claims, wherein the valve member (6) is constructed as a flap, which is pivotable about a shaft (A) and whose closed position may be blocked with the aid of a safety lever (8), wherein the safety lever (8) operates a switching means (10) which blocks the external power drive (5) in a released position of the safety lever.
8. A pipe cleaning system as claimed in claim 7, wherein the safety lever (8) and the closure flap (6) are mutually mechanically lockable with the aid of a detent system (7, 9).
9. A pipe cleaning system as claimed in one of the preceding claims, wherein at least one switching element (10) is constructed in the form a switchable valve, which at the same time, as a switching element in a switch
position representing the insertion or removable process, directly or indirectly blocks a pressure medium supply to the hydraulic or pneumatic external power drive (5).
10. A pipe cleaning system as claimed in claim 9, wherein the valve (10) is switchable mechanically, electromechanically or electromagnetically.
11. A pipe cleaning system as claimed in one of the preceding claims, wherein at least one switching element (10) is constructed in the form of an electric switch which, in a switch position representing the insertion or removal process, directly or indirectly prevents a supply of electric power to an electric external power drive.
12. The pipe cleaning system as claimed in one or more of the preceding claims installed in the conveyor line of a viscous material pump.
4131-delnp-2005-complete specification (granted).pdf
|Indian Patent Application Number||4131/DELNP/2005|
|PG Journal Number||01/2009|
|Date of Filing||13-Sep-2005|
|Name of Patentee||SCHWING GMBH|
|Applicant Address||HEERSTRASSE 11, 44647 HERNE, GERMANY.|
|PCT International Classification Number||B08B 9/04|
|PCT International Application Number||PCT/EP2004/001773|
|PCT International Filing date||2004-02-23|