GB1564827A

GB1564827A - Suction apparatus for textile machines

Info

Publication number: GB1564827A
Application number: GB4013076A
Authority: GB
Original assignee: Luwa Ltd
Current assignee: Luwa Ltd
Priority date: 1975-10-03
Filing date: 1976-09-28
Publication date: 1980-04-16
Also published as: IT1072946B; FR2326491A1; JPS5246125A; FR2326491B3; DE2643654A1; CH604828A5

Description

(54) SUCTION APPARATUS FOR TEXTILE MACHINES (71) We, LUWA AG, a Swiss Body Corporate of Anemonenstrasse 40, 8047 Zurich, Switzerland, do hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement : The present invention relates to a new and improved construction of a suction apparatus for cleaning air charged with fibers and dust obtained from the vicinity of a textile machine.

It is known that in textile machines, especially drawing frames which are equipped with suction devices, the quantity of material which is to be sucked-off and to be filtered, is of rather considerable volume and, in the case of drawing frames in the wool or linen industry, possess an extremely large content of fine dust.

The formed waste quantities can amount to 1% of the processed material and more, in other words for instance for 300 kg/h of process material the waste may comprise 300 gr/h.

The large quantities of air which are needed for the suction cleaning operation exceed by far the quantities required for the climatization of the machine room.

At least a part of the exhaust air should be sufficiently cleaned, and returned directly into the room or forced back into the machine. In the woollen industry there exists a further problem due to the processing of dyed goods. The large quantities of air which are returned into the room must be distributed almost free of drafts, otherwise fibers of one color can be de- posited upon slivers or banks of another color, leading to considerable damage of the processed materials.

There are known to the art suction installations for gill boxes which possess a filter box connected with the suction device at the end of the creel. Also attempts have already been made to erect an automatic filter drum at the end of the creel. However, these devices were not capable of solving the distribution problem existing with larger quantities of air.

According to the present invention there is provided a suction apparatus for cleaning air charged with fibres and dust obtained from the vicinity of a textile machine, such apparatus comprising an elongated channel having a single inlet at one end thereof and a outlet at the opposite end thereof, suction means provided at said inlet end for supplying air to be cleaned into said inlet end of the channel and a collection device for separated fibres and dust connected to th- outlet end of the channel, said channel comprising two planar, spaced apart filter walls for filtering dust from air passing through the walls from the interior of the channel defined between said filter walls in use of the apparatus, the width of the walls trans tersely of the direction of extent of the channel being greater than the spacing between the walls.

The invention will be better understood and will become further apparent when consideration is given to the following detailed description with reference to the accompanying drawings, wherein: Figure 1 illustrates in schematic elevational view a suction apparatus according to a first exemplary embodiment; Figure 2 Is a cross-sectional view taken substantially along the line II-II of Figure 1; Figure 3 is a cross-sectional view through the suction apparatus according to a second exemplary embodiment; and Figure 4 illustrates in elevational view the suction apparatus of Figure 3.

Describing now the drawings, in Figures 1 and 2 reference character 2 designates an elongated substantially horizontally extending channel or channel means which communicates at its inlet end 6 with outlet connection 10 of a ventilator 8 having a powered impeller fan. The ventilator 8 possesses a suction connection 12 which is connected with a non-illustrated collection conduit of the suction device of a textile machine, for instance a gill box.

At the outlet end 14 of the channel 2 there is connected a settling box 16 with a collecting bag or sack 18 detachably secured to its underside. The channel 2 is composed of a number of lengthwise sections 20 which are sealingly connected with one another in any convenient manner. The channel 2 possesses a rectangular outline or contour containing a substantially U-shaped unobstructed cross-section or portion 22.

The U-shaped portion 22 is defined between leg 45 and 47 which are formed by substantially vertical air permeable walls 24 and 26, whereas the base 49 and the web 51 defining the bight of the U-shaped crosssection 22, respectively, possess air impervious walls 28 and 30. The ends of the legs 45 and 47 of the U-shaped portion 22 are closed by a plate 32 which possesses a perforated sheet metal portion or apertured plate 34 located between the legs. Hence, the inner space 36 bounded by the U-shaped portion 22 and the plate 32 communicates via holes, not shown, of the perforated sheet metal portion 34 with the atmosphere.

The channel 2 and the perforated or apertured plate 32 can serve as part of a support for a feeding frame schematically illustrated in Figures 1 and 2, the pairs of feed rolls 38 of which are secured to the supports 40. The channel 2 thus extends in the lengthwise direction of a drawing frame (not shown), the feeding frame forming a part thereof.

Due to its profile the channel 2 is extremely suitable from its strength standpoint as a support for the feeding frame.

However, its decisive advantage resides in the fact that a large proportion of the surface defining the sides of the U-shaped portion 22 consists of air pervious walls in relation to the cross-sectional surface, the width of the air pervious walls transversely of the direction of extent of the channel being greater than the spacing between the outer walls defining the rectangular crosssection channel. This is due to the crosssectional shape. The walls 24 and 26 are designed as filter surfaces. Each of these walls 24 and 26 consist of two parallel perforated sheet metal plates 42 and 44 which are spaced from one another by the thickness of a foam mat 46 located therebetween.The walls 24 and 26 can be constituted by structural units of a length corresponding to that of the sections 20 of the channel 2 and can be exchangeably connected, for instance, by means of conventional quick-operating closures or snap closure eiements (not shown). In each of the herein disclosed embodiments the outer filter walls constitute the long or lengthwise sides of a rectangle when the channel is viewed in cross-section. Preferably the sides of this rectangle have a ratio of at least 5:1.

By virtue of the large peripheral proportion of filter surfaces which are provided by the walls 24 and 26, related to the crosssectional area of the channel, such is capable of handling large air quantities notwithstanding low pressure drop.

The air conveyed by the ventilator or fan 8 is distributed at a large filter surface, so that its exit from the channel 2, especially through the walls 24, takes place at low velocity i.e. is relatively diffuse. The air departing through the walls 26 collects at the internal space of the compartment 36 into an air current effluxing through the sheet metal portion 34, however such, when it is directed upwardly, neither disturbs the operating personnel nor the operation of the drawing frame. The air departing from the channel 2 generally has the tendency of preventing entry and deposition of contaminents from the room or ambient air at the drawing frame.

Since the flow velocity at the inlet end 6 of the channel 2 is relatively high, for instance 15 ml sec, there occurs a separation of the coarser contaminants at the walls 24 and 26. To the extent that such contaminents even contact these walls, they are continously "flushed away" by the air flow and finally arrive at the settling box or compartment 16. Contamination of the walls 24 and 26, to the extent that the air conveyed by the ventilator contains fine dust, however cannot be avoided. Since such fine dust settles at the waii surfaces i.e.

in the pores of the filter material, it is necessary to periodically exchange or clean these walls 24 and 26.

The contaminents reaching the settling box or compartment 16, in the event that the bag or sack 18 is formed of an air pervious or formanious material, is conveyed directly into such bag with the aid of a residual air current. Otherwise the residual air escapes through the air pervious walls of the settling compartment, whereas the contaminents drop into the sack. In the settling box of compartment 16 there also can be arranged a sack tamper or plunger, not illustrated, which periodically presses the fibers collecting in the settling box 16 into the sack 18 and at that location compacts the same.

While in the embodiment illustrated in Figures 1 and 2 the cross-sectional surface of the channel 2 remains constant over its length, in order to take into account the quantity of air which decreases in the flow direction, it is possible gradually or stepwise in sections to reduce the effective crosssection in such direction. In this respect it can be advantageous if the filtering channel periphery is not reduced or not reduced to the same degree as the cross-sectional area.

An exemplary embodiment of a channel having a cross-section which reduces in the flow direction has been shown in Figures 3 and 4. The channel 52, which is again connected to a ventilator or fan 58 and with a settling box, not illustrated, possesses a rectangular cross-section 60, and the longitudinal sides or walls 54 are air pervious and in their construction correspond to the surfaces 24 of Figures 1 and 2. The shorter sides 56 of the rectangular crosssection 60 are formed by plates or profile members which are impervious to air.

As will be apparent from the showing of Figure 4 baffle plates 62, which are secured to the upper plate 56, are distributed over the length of the channel 52 and which, as best seen by referring to Figure 3, block part of the cross-section of such channel 60. The front surface of the baffle plates 62, viewed in the flow direction of the air through the channel 60, increases, as indicated by the inclination of the projection bne 64 (Figure 4) which interconnects the lower structure or end of each of the baffle plates 62 with one another.

The width of the baffle plates 62 can be constant, and such is smaller than the width of the cross-section of the channel 60. The baffle plates 62 are arranged such that there remain at both sides thereof the gaps 66 which render possible passage of the air flow along the surface of the walls 54.

The baffle plates 62, due to their distribution with increasing size, ensure that the initial flow velocity remains practically constant over the entire length of the channel 60. A corresponding effect could also be obtained by means of a filler body arranged in the channel which increases in cross-section in the flow direction.

The deposition of fine dust in the pores of the filtering surface-which cannot be completely prevented--resufts in a gradual increase in the pressure drop at the filter and thus a corresponding decrease in the suction capacity of the ventilator. Since such drop in the suction capacity, in certain instances, can result in a disturbance in the operation of the machine which is serviced by the suction device (for instance a drawing frame for long-staple fibers which is encased and at which there must be maintained constant flow conditions) measures can be provided in order to compensate for the increase in the pressure drop at the filter.

As will be apparent from the showing of Figure 4, the housing 70 of the ventilator 58 is provided at the periphery of the suction connection 72- with an opening 74 which can be regulated or closed by a flap member 76 or equivalent structure. A pneumatic adjustment motor 78 pivots the flap member 76, against the action of a return spring (not shown) in the closing direction when the pressure increases in a compressed air conduit 80 connected with the adjustment motor 78. The pressure in the conduit 80 is determined by an adjustable control valve 82, which, on the one hand is connected with a compressed airsupply conduit 84 and, on the other hand, is connected via a control line 86, upstream with regard to the ventilator 58, to the suction system. The control valve 82 can be adjusted by means of an adjustment screw 88 to a predetermined swinging pressure.

If, due to coating or covering of the walls 54 to the channel 52 with the fine dust, the negative pressure in the suction system drops, then the control valve 82 opens and allows compressed air to flow from the supply line or conduit 84 to the adjustment motor 78. As a function of the pressure increase in the adjustment motor 78 and in the conduit SO the flap member 76 is rocked in the dosing direction until, due to a corresponding increase m the negative pressure in the suction system to the set or adjusted value, the control valve 82 again closes. The flap member 76 remains in the corresponding position until there is again triggered a compensation movement due to dropping of the negative pressure.

If the flap member 76 approaches the completely closed position, which, for instance, can be indicated by means of a signal triggered by a proximity switch, then there now must occur a cleaning of the channel or exchange of the walls. In lieu of, or in addition to, triggering a signal a current circuit containing the proximity switch also can cause stoppage of the drawing frame or other machine. This can be of significance in those mstances where there must be prevented that the operation occurs or continues under conditions which deviate from a reference state or condition such as for instance the negative pressure, prescribed for maintenance of a predeter mined quality standard.

After cleaning of the channel has been completed and prior to again placing into operation the drawing frame the flap member 76 again must be opened by venting the conduit 80 under the action of the restoring or return spring of the adjustment motor 78. The apparatus then again is in a condition for maintaining a constant suction pressure during a predetermined dura tion of operation, notwithstanding increasing coating or contamination of the filter.

Although the pressure compensation described in conjunction with the exemplary embodiments employing throttling or false air regulation by means of a compensation flap, presupposes the use of a more efficient ventilator, due to increasing the operating time of the filter walls and avoiding interruption in the operation for the exchange of the walls, there Is realized a better quality of the processed textile material along with an increased production efficiency of the machine serviced by the suction system.

The pressure compensation is also possible by changing the delivery capacity of the ventilator, for instance by regulation of its rotational speed. A construction utilizing a compensation shutoff element, however, has the advantage that it is simpler and thus less expensive. On the other hand, the compensation flap member also can be arranged as a throttle flap member at the outlet of the ventilator or at the inlet of the filter channel and can correspondingly increase the throughflow crosssection with increasing contamination or coating of the filter walls, in order to thereby compensate the pressure drop.

According to a preferred constructual manifestation of the suction apparatus, such also possesses a protective device in order to avoid the cause of disturbances at the textile machine during starting and stopping thereof. The drive motors of textile machines and ventilators are usually powered by the same current circuit and thus switching-on and switching-off thereof occurs simultaneously. However, the ventilator, when it is turned-on, reaches its normal operating speed much more quickly than the textile machine, and when turnedoff, the suction effect of the ventilator is maintained under certain circumstances after the machine already has been completely stopped.Experience has shown that for the textile machines of the types being envisaged, the suction action produced by the ventilator at the work locations should become effective only when the machine has reached its operating rotational speed. Conversely, the suction action then must stop practically suddenly when the machine runs down. Otherwise, there is the danger of sucking-up valuable fiber material or that sliver or fiber rupture will occur, especially if the sliver or fiber is not or no longer completely tensioned.

According to a preferred embodiment of the invention, the protecive device is combined with the means for the compensation of the pressure drop at the filter surfaces in a manner such that there is partially made use of the same elements. In particular, when using a compensation flap member, either as a throttle flap member or as a false air flap member, this flap member also can be employed with the protecive device.

The protective device has been illustrated in Figure 4 in conjunction with the therein illustrated false air flap member 76 and its control Mounted in the line 80 is an actuation member in the form of for instance a 3/2-way magnetic vaive 89 which, upon shutting-off the textile machine, is no longer placed under current, frees the path between the locations 80 and 91 and, at the same time blocks the path from location 90 to location 80. As a consequence, the adjustment motor 78 is vented and flap member 76 suddenly opens. Since upon restarting of the machine and the ventilator the valve 89 is again placed under current, such frees the path from location 90 to location 80, whereas the path from location 80 to claim 91 Is blocked.In order to ensure that now the flap member 76 will slowly travel into the position determined by the control valve 82, a throttle 92 defining a time-delay element is niounted in the line 90. The suction action at the machine then begins after its moved or rotating parts have reached their normal operating speed.

Finally, it is to be stated that the described channel with its lengthwise sides or U-legs could also be arranged horizontally or inclined instead of (as illustrated) vertically. Yet, the vertical arrangemen has the advantage that the effects of gravity upon the separation operation act in the same manner-if at all L ' ?ble-- at both confronting filter walls.

WHAT WE CLAIM IS: 1. A suction apparatus for cleaning air charged with fibres and dust obtained from the vicinity of a texile machine, such apparatus comprising an elongated channel having a single inlet at one end thereof and an outlet at the opposite end thereof, suction means provided at said inlet end for supplying air to be cleaned into said inlet end of the channel and a collection device for separated fibres and dust connected to the outlet end of the channel, said channel comprising two planar, spaced apart filter walls for filtering dust from air passing through the walls from the interior of the channel defined between said filter walls in use of the apparatus, the width of the walls transversely of the direction of extent of the channel being greater than the spacing between the walls.

2. Apparatus as claimed in claim 1, wherein the width of the walls is at least five times the spacing between the walls.

3. Apparatus as claimed in claim 1 or 2, wherein said channel extends substantially

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

Claims

**WARNING** start of CLMS field may overlap end of DESC **. tion of operation, notwithstanding increasing coating or contamination of the filter. Although the pressure compensation described in conjunction with the exemplary embodiments employing throttling or false air regulation by means of a compensation flap, presupposes the use of a more efficient ventilator, due to increasing the operating time of the filter walls and avoiding interruption in the operation for the exchange of the walls, there Is realized a better quality of the processed textile material along with an increased production efficiency of the machine serviced by the suction system. The pressure compensation is also possible by changing the delivery capacity of the ventilator, for instance by regulation of its rotational speed. A construction utilizing a compensation shutoff element, however, has the advantage that it is simpler and thus less expensive. On the other hand, the compensation flap member also can be arranged as a throttle flap member at the outlet of the ventilator or at the inlet of the filter channel and can correspondingly increase the throughflow crosssection with increasing contamination or coating of the filter walls, in order to thereby compensate the pressure drop. According to a preferred constructual manifestation of the suction apparatus, such also possesses a protective device in order to avoid the cause of disturbances at the textile machine during starting and stopping thereof. The drive motors of textile machines and ventilators are usually powered by the same current circuit and thus switching-on and switching-off thereof occurs simultaneously. However, the ventilator, when it is turned-on, reaches its normal operating speed much more quickly than the textile machine, and when turnedoff, the suction effect of the ventilator is maintained under certain circumstances after the machine already has been completely stopped.Experience has shown that for the textile machines of the types being envisaged, the suction action produced by the ventilator at the work locations should become effective only when the machine has reached its operating rotational speed. Conversely, the suction action then must stop practically suddenly when the machine runs down. Otherwise, there is the danger of sucking-up valuable fiber material or that sliver or fiber rupture will occur, especially if the sliver or fiber is not or no longer completely tensioned. According to a preferred embodiment of the invention, the protecive device is combined with the means for the compensation of the pressure drop at the filter surfaces in a manner such that there is partially made use of the same elements. In particular, when using a compensation flap member, either as a throttle flap member or as a false air flap member, this flap member also can be employed with the protecive device. The protective device has been illustrated in Figure 4 in conjunction with the therein illustrated false air flap member 76 and its control Mounted in the line 80 is an actuation member in the form of for instance a 3/2-way magnetic vaive 89 which, upon shutting-off the textile machine, is no longer placed under current, frees the path between the locations 80 and 91 and, at the same time blocks the path from location 90 to location 80. As a consequence, the adjustment motor 78 is vented and flap member 76 suddenly opens. Since upon restarting of the machine and the ventilator the valve 89 is again placed under current, such frees the path from location 90 to location 80, whereas the path from location 80 to claim 91 Is blocked.In order to ensure that now the flap member 76 will slowly travel into the position determined by the control valve 82, a throttle 92 defining a time-delay element is niounted in the line 90. The suction action at the machine then begins after its moved or rotating parts have reached their normal operating speed. Finally, it is to be stated that the described channel with its lengthwise sides or U-legs could also be arranged horizontally or inclined instead of (as illustrated) vertically. Yet, the vertical arrangemen has the advantage that the effects of gravity upon the separation operation act in the same manner-if at all L ' ?ble-- at both confronting filter walls. WHAT WE CLAIM IS:

1. A suction apparatus for cleaning air charged with fibres and dust obtained from the vicinity of a texile machine, such apparatus comprising an elongated channel having a single inlet at one end thereof and an outlet at the opposite end thereof, suction means provided at said inlet end for supplying air to be cleaned into said inlet end of the channel and a collection device for separated fibres and dust connected to the outlet end of the channel, said channel comprising two planar, spaced apart filter walls for filtering dust from air passing through the walls from the interior of the channel defined between said filter walls in use of the apparatus, the width of the walls transversely of the direction of extent of the channel being greater than the spacing between the walls.

horizontally with said filter walls being arranged substantially vertically.

4. Apparatus as claimed in claim 1 2 or 3, wherein the effective cross-sectional area of the channel is reduced progressively from its inlet end to its outlet end.

5. Apparatus as claimed in claim 1, 2, 3, or 4, wherein the channel has a rectangular cross-section.

6. Apparatus as claimed in claim 1 2, 3 or 4, wherein the cross-section of said channel is substantially U-shaped.

7. Apparatus as claimed in any one of claims 1 to 5, further including baffle plates distributed along the length of the channel and extending transversely with respect to the flow direction of the air lengthwise of the channel, said baffle plates extending in spaced relationship from the filter walls and, vidwed in the flow direction, with each downstream baffle plate blocking a larger portion of the cross-section of the channel means than an upstream located baffle plate.

8. Apparatus as claimed in any preceding claim further including means for compensating for pressure drop across the filter walls.

9. Apparatus as claimed in any one of olaims 1 to 7, wherein said suction means includes an air impeller, and a control flap member operatively associated with said ventilator.

10. Apparatus as claimed in claim 9, wherein the impeller has a suction side provided with an opening, said flap member serving for closing said opening and means for actuating the flap member as a function of changes in the negative pressure.

11. Apparatus as claimed in claim 9 or 10, further including actuation means and time-delay means for controlling the flap member.

12. A suction apparatus for cleaning air charged with fibers and dust for a textile machine, constructed and arranged to operate substantially as hereinbefore de scribed with reference to and as shown in Figures 1 and 2 or Figures 3 and 4 of the accompanying drawings.

13. A textile machine including the suction apparatus of any preceding claim, and having a drawing frame including pairs of feed rolls supported by the channel of the suction apparatus.