GB1579706A

GB1579706A - Sandblasting chamber floor

Info

Publication number: GB1579706A
Application number: GB932377A
Authority: GB
Original assignee: SCHLICK KG HEINRICH
Current assignee: SCHLICK KG HEINRICH
Priority date: 1976-03-04
Filing date: 1977-03-04
Publication date: 1980-11-19
Also published as: CH619633A5; DE2608847B2; DE2608847A1; FR2342822A1; NL7702193A; DE2608847C3; FR2342822B1; AT346725B; BE852079A; ATA142377A

Abstract

Such a floor which is borne by foundation blocks (38) and rolled beams has a grid floor (16) and a goffered floor (20) therebeneath. The latter has funnels (19) which are arranged in V-shaped collecting load-bearing members (39) and are intended for receiving abrasive and abraded material. These funnels are connected, by means of their emptying openings (30), to suction lines (21). The suction lines (21) comprise tubes which consist of elastomeric plastic and are fixedly connected to trough walls; they can be produced cost-effectively and can be easily mounted and repaired. <IMAGE>

Description

(54) SANDBLASTING CHAMBER FLOOR (71) We, HEINRICH SCHLICK KG GmbH & Co., a Kommanditgesellschaft organised under the Laws of the Federal Republic of Germany, of 24 Grevener Strasse, 4402 Greven-Reckenfeld, German Federal Republic, 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: This invention relates to a sandblasting chamber floors.

Sandblasting chamber floors have been proposed in which collecting funnels are disposed adjacent one another in contiguous relationship and longitudinal ducts are connected to said funnels for discharging a blasting agent collected in the collecting funnels, the blasting agent flowing into the longitudinal duct through holes in the collecting funnels. The longitudinal ducts are formed, for example, as ducts disposed beneath the collecting funnels and defined by two vertical partitions provided between two floor plates disposed beneath the funnels. The disadvantage of this type of construction is that the floor must be constructed practically as a double floor so that the overall height is increased as are also the building costs.

It has already also been proposed to provide a slot or opening in the side wall of each collecting funnel and to construct the side wall formed with the slot as part of the longitudinal duct (German Patent Spec. 1 217 240). With this system, the funnel side walls disposed in a row form a wall of the longitudinal duct for the discharge of the blasting agent and thus serve a double purpose. In one form of construction according to the latter prior art, two supporting plates are disposed inside two side walls of the funnel and also form part of the longitudinal duct and converge in the suction direction.

Numerous examples of sandblasting chambers with a floor according to the latter prior art have been constructed but it has been found that such floors have two basic disadvantages: Firstly, the construction from thin-walled sheet-metal welded together by difficult and expensive manual labour is relatively expensive and secondly the throughput of highly abrasive blasting agent means that the longitudinal duct walls are subjected continually to wear so that repair must be expected after a relatively short time. For such repair work, however, entire parts of the floor have to be cut out and replaced. A repair of a prior-art floor is usually not worthwhile, therefore, so that full replacement is required.

Many clients also think it a disadvantage that the sheet metal structure can take only a relatively low loading unless the material costs are to be uneconomically high.

According to the present invention we provide a sandblasting chamber floor comprising collecting funnels disposed adjacent one another in contiguous relationship and longitudinally extending ducts connected to said funnels for discharging a blasting agent collected in said funnels, said funnels having outlet holes and said ducts having openings at least in the region of said outlet holes so that in operation blasting agent will flow through said outlet holes and openings into said ducts, and wherein the ducts comprise tubes of abrasion-resistant, elastic or thermoelastic plastics material.

It is possible in simple manner so to construct the tube that its cross section is divergent, to ensure a uniform flow. With regard to the prior art, for example, reference may be made to Figure 9 of U.S. Patent Specification No. 2 912 918 and the associated description. The construction of the tube as a slightly divergent conical surface means that there is a uniform pressure at all the openings and hence a uniform flow is ensured. The forces and laws operative in these conditions are known so that appropri ate dimcnsioning of the ducting crosssections is possible according to the type of construction, length of the longitudinal ducting and number of funnels to be served.

The problem of achieving a uniform flow has also been considered by earlier workers and a solution proposed which comprises welding in additional guide plates to produce a gradual construction of the ducting and hence equalize the pressure gradient. However, highly qualified skiller workers are required to weld in the guide plates and they have to pay very careful attention to the exact angular positions. Since however, the guide plates are also subject to gradual wear, the repair generally does not guarantee that the replaced plates are at the correct angles to one another and hence produce optimum pressure gradients.

if a plastics tube is provided from the outset, however, it can be accurately dimensioned. A tube can be made most simply from a slightly convergent trapezoidal web by bending the same. More particularly, it is proposed to make the tube from a perma ncntly elastic rubber-like material. In these conditions either the edges of the tube can be welded together or be spaccd apart, a slot forming. The latter system can be installed particularly easily if a sandblasting chamber floor is provided in which a row of funnels compriscs a V-shaped trough or channel with inscrted wall elements, the funnel holes lying in a row. The tube bent from a flat web then has a longitudinal slot defined by the web edges. The tube can be secured to the outer surface of the wall of the trough or channel so that the funnel hole row coincides with the longitudinal slot.Fixing may be carried out beneath the apex of the trough or channel, although preferably laterally thereof.

It is noted that the provision of lateral openings in a funnel has been proposed in US Patent Spec. 2 912 918.

To make the entire floor much casicr to service, it is proposed that the troughs or channels and the tube may be adapted to be disposed directly on a supporting structure.

If the troughs or channels are disposed directly on a supporting structure, they need not of themselves take forces of the kind necessary in some of the floors according to the prior art. By arranging the floor so that the supporting structure makes only partial contact with the troughs or channels it is therefore possible to make at least those parts of the troughs or channels plastics. This makes the floor parts much cheaper.

As an alternative to the possiblity of associating a longitudinal duct with just one funnel row it is possible to connect pairs of collecting funnel rows to a common longitudinal duct, the latter being formed from two bent webs.

Preferred embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings in which: Figure l is a diagrammatic elevation of a sandblasting chamber; Figure 2 is a partial perspective view of the floor of the chamber of Figure 1, Figure 3 is an enlarged partial view of the floor in section viewed in the direction of arrow III in Figure 2.

Figure 4 is a section including the line IV-IV in Figure 2.

Figure 5 is a similar view to Figure 3, but with a longitudinal duct associated with pairs of funnel rows in each case.

Referring to Figure 1 the sandblasting chamber bearing the general reference 10 is defined by walls and has a roof 15. The chamber has a latticework floor 16 preferably comprising grids or perforate plates.

The sandblaster 17 stands on the floor as he sandblasts an article 18. Since the articles for sandblasting are frequently very heavy, the floor must be of appropriate load-carrying design.

Beneath the latticework floor 16 is a honeycomb pattern floor 20 through which the blasting agent and the abraded material drop. An air flow is also produced continuously through the floors 16 and 20 to keep the air within the sandblasting chamber clear and extract the granular material falling through the honcycomb floor. A row of ducting 21 is disposed in the region of the honeycomb floor and feeds the air flow via a reception station 22 to duct 23 leading to a concentrator 24. The sandblasting agent is recovered via appropriate separator and filter devices 25, which may, for example, comprise a cyclone separator, and is fed via hose 27 to the sandblaster. The air passing through the apparatus can be clcaned by means of special separators 29 and discharged to atmospherc.

Figure 2 shows the floor of the sandblasting chamber in an enlarged scale. The bottom part or honeycomb floor 20 consists of a number of collecting funnels 19 disposed adjacent one another in contiguous relationship and into which the blasting agent and the abraded material fall and through which the chamber ventilation air is extracted in the downward direction. The funnels 19 are disposed uniformly in rows At their centrcs, i.e.

their bottom part, they have holes 30 connected to ducting 21. The ducting extends between and parallel to the rows of funnels so that the blasting agent can be taken through it.

The latticework floor 16 resting on the honeycomb floor in the illustrated embodi mcnt consists of perforate steel plates. wire netting and the like. It is sufficicntly strong to bear the sandblaster and his equipment and the article for sandblasting. For example, the steel plate may be 6 mm thick and have 12 mm diameter bores so spaced as to leave 45-55% of the floor surface between the bores.

In the exemplified embodiment, a row of funnels consists of a V-shaped channel 39 connected at the apex and, for example, having side walls at right angles to one another.

The channels or troughs 39 are divided by roof-shaped inserts 43 to form rows of funnels. The connection between the channels 39 and the inserts 43 is advantageously stitched, welded or, when made from plastics, glued.

The entire floor structure is mounted on rows of foundation blocks 38 made of concrete and crowned by a double-T girder 37.

At their top edges the channels have supporting cheeks by means of which they are supported on the girders 37. They are fitted practically loosely and can be removed without difficulty after the latticework floor 16 has been removed. Preferably at least the inclined side walls of the channels are made of plastics material.

The ducts 21 are secured to the channels 39 on the outside in the bottom region. The ducts are formed by bending over a slightly convergent trapezoidal web. A particularly suitable material for this puspose is a vulcanized fibre-reinforced polymer of the like, more particularly rubber-like abrasionresistant materials of the kind known for hoses and the like from sandblasting technology. The edges of the web of material are fixed laterally to an outer wall 40 of the channel 39, e.g. by riveting. In these conditions the edges do not rest upon one another but form a slot 41 which coincides exactly with the openings 30. Since the duct is rigidly connected to the channel, it is lifted out when the channel is lifted from the foundation blocks. Repair or replacement is thus possible without any appreciable interruption.

The material of the longitudinal ducts also wears much less quickly than steel so that longer lives are possible. A uniform air flow must be maintained in each funnel 19 to obtain a uniform downward draught in the sandblasting chamber and effective conveyance of the entrained particles. The pressure in each duct 21 at the outflow end, near the collector 22, is less than at the inflow end, because a pressure drop is required along the duct to achieve a substantially constant speed of conveyance in the duct. The holes 30 thus decrease in size proportionally towards the suction end so that exact equilibrium is obtained between the duct pressure and the size of the opening in each funnel.

The flow through the ducts 21 is ensured by means of openings at the duct end 51 (see Figure 4).

Figure 5 shows another embodiment in which each two channels or troughs are combined to form a twin trough 49. The outgoing air and abraded material are removed via the duct 48 adapted to transport relatively large quantities and having an opening slot 47 on each side. The slots 47 coincide with holes 46. Duct 48 is of substnatially two-shell construction, each shell being secured by its edges to the side walls of the twin trough as will be seen from Figure 5. To obtain a varying opening, a buckle is disposed substantially in the middle of the duct 48 to allow a specific opening fot the air duct. It has been found that where an elastomeric material is used for the ducts 23 and 48 they collapse somewhat in the static state (i.e. without air flow). When, however, the blasting chamber ventilation is switched on, the ducts are forced apart and form the ideal required cross-section.In these conditions they also adapt to the existing walls and boundaries of the channel walls.

Figure 4 is a cross-section showing how the ducts 23 and 48 are disposed beneath the latticework floor 16, the increasing crosssection being particularly visible.

It will be apparent that in the preferred embodiments described the use of a tube as a longitudinal duct made from an elastomeric material enables the problems mentioned hereinbefore to be solved in a very simple manner. It is also possible to achieve a very flat floor construction because the tube can be disposed laterally. Preliminary experience with embodiments of the new floor clearly shows that floor life is increased while on the other hand assembly and maintenance are greatly simplified and costs reduced so that sandblasting chambers equipped with the floor can be utilized much more rationally.

WHAT WE CLAIM IS: 1. A sandblasting chamber floor comprising collecting funnels disposed adjacent one another in contiguous relationship and longitudinally extending ducts connected to said funnels for discharging a blasting agent collected in said funnels, said funnels having outlet holes and said ducts having openings at least in the region of said outlet holes so that, in operation blasting agent will flow through said outlet holes and openings into said ducts, and wherein the ducts comprise tubes of abrasion-resistant, elastic or thermo-elastic plastics material.

2. A floor according to Claim 1, wherein the tubes are formed from slightly convergent trapezoidal webs by bending the same.

3. A floor according to Claim 1 or Claim 2, wherein the tubes are formed from permanently elastic rubber-like material.

4. A floor according to Claim 2 or Claim 3 when appendent to Claim 2, wherein the funnels are arranged in rows, each row being formed by a V-shaped trough or channel with inserted wall elements, the outlet holes of

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

Claims

**WARNING** start of CLMS field may overlap end of DESC **. steel plate may be 6 mm thick and have 12 mm diameter bores so spaced as to leave 45-55% of the floor surface between the bores. In the exemplified embodiment, a row of funnels consists of a V-shaped channel 39 connected at the apex and, for example, having side walls at right angles to one another. The channels or troughs 39 are divided by roof-shaped inserts 43 to form rows of funnels. The connection between the channels 39 and the inserts 43 is advantageously stitched, welded or, when made from plastics, glued. The entire floor structure is mounted on rows of foundation blocks 38 made of concrete and crowned by a double-T girder 37. At their top edges the channels have supporting cheeks by means of which they are supported on the girders 37. They are fitted practically loosely and can be removed without difficulty after the latticework floor 16 has been removed. Preferably at least the inclined side walls of the channels are made of plastics material. The ducts 21 are secured to the channels 39 on the outside in the bottom region. The ducts are formed by bending over a slightly convergent trapezoidal web. A particularly suitable material for this puspose is a vulcanized fibre-reinforced polymer of the like, more particularly rubber-like abrasionresistant materials of the kind known for hoses and the like from sandblasting technology. The edges of the web of material are fixed laterally to an outer wall 40 of the channel 39, e.g. by riveting. In these conditions the edges do not rest upon one another but form a slot 41 which coincides exactly with the openings 30. Since the duct is rigidly connected to the channel, it is lifted out when the channel is lifted from the foundation blocks. Repair or replacement is thus possible without any appreciable interruption. The material of the longitudinal ducts also wears much less quickly than steel so that longer lives are possible. A uniform air flow must be maintained in each funnel 19 to obtain a uniform downward draught in the sandblasting chamber and effective conveyance of the entrained particles. The pressure in each duct 21 at the outflow end, near the collector 22, is less than at the inflow end, because a pressure drop is required along the duct to achieve a substantially constant speed of conveyance in the duct. The holes 30 thus decrease in size proportionally towards the suction end so that exact equilibrium is obtained between the duct pressure and the size of the opening in each funnel. The flow through the ducts 21 is ensured by means of openings at the duct end 51 (see Figure 4). Figure 5 shows another embodiment in which each two channels or troughs are combined to form a twin trough 49. The outgoing air and abraded material are removed via the duct 48 adapted to transport relatively large quantities and having an opening slot 47 on each side. The slots 47 coincide with holes 46. Duct 48 is of substnatially two-shell construction, each shell being secured by its edges to the side walls of the twin trough as will be seen from Figure 5. To obtain a varying opening, a buckle is disposed substantially in the middle of the duct 48 to allow a specific opening fot the air duct. It has been found that where an elastomeric material is used for the ducts 23 and 48 they collapse somewhat in the static state (i.e. without air flow). When, however, the blasting chamber ventilation is switched on, the ducts are forced apart and form the ideal required cross-section.In these conditions they also adapt to the existing walls and boundaries of the channel walls. Figure 4 is a cross-section showing how the ducts 23 and 48 are disposed beneath the latticework floor 16, the increasing crosssection being particularly visible. It will be apparent that in the preferred embodiments described the use of a tube as a longitudinal duct made from an elastomeric material enables the problems mentioned hereinbefore to be solved in a very simple manner. It is also possible to achieve a very flat floor construction because the tube can be disposed laterally. Preliminary experience with embodiments of the new floor clearly shows that floor life is increased while on the other hand assembly and maintenance are greatly simplified and costs reduced so that sandblasting chambers equipped with the floor can be utilized much more rationally. WHAT WE CLAIM IS:

1. A sandblasting chamber floor comprising collecting funnels disposed adjacent one another in contiguous relationship and longitudinally extending ducts connected to said funnels for discharging a blasting agent collected in said funnels, said funnels having outlet holes and said ducts having openings at least in the region of said outlet holes so that, in operation blasting agent will flow through said outlet holes and openings into said ducts, and wherein the ducts comprise tubes of abrasion-resistant, elastic or thermo-elastic plastics material.

each row of funnels lying in a row, each tube being formed by bending a flat web and having a longitudinally extending slot defined by the web edges and being secured to the outer surface of the wall of a channel or trough so that the row of outlet holes of the channel or trough coincides with the longitudinal slot.

5. A floor according to Claim 4, wherein the outlet holes are located at or close to the bases of the troughs or channels and the tubes are disposed laterally of the troughs or channels.

6. A floor according to Claim 4 or Claim 5, wherein part of the floor consisting of the troughs or channels and the tubes is adapted to be disposed directly on a supporting structure.

7. A floor according to Claim 4, 5 or 6 wherein the troughs or channels are supported directly on a structure making partial contact with the troughs or channels and at least those parts of the troughs or channels not making direct contact with the supporting structure and made from plastics material.

8. A floor according to Claim 1, 2 or 3, wherein the funnels are arranged in rows and adjacent pairs of the rows are connected to a common duct formed from two bent webs.

9. A floor for a sandblasting chamber substantially as hereinbefore described with reference to Figures 1 to 4 alone or as modified by Figure 5 of the accompanying drawings.