US2228636A

US2228636A - Method of making tubular bodies

Info

Publication number: US2228636A
Application number: US160596A
Authority: US
Inventors: Magnani Alessandro
Original assignee: FLSmidth and Co AS
Current assignee: FLSmidth and Co AS
Priority date: 1937-03-03
Filing date: 1937-08-24
Publication date: 1941-01-14
Anticipated expiration: 1958-01-14

Description

Jan. 14, 1941. A. MAGNANI 2,

' v METHOD OF MAKING TUBULAR BODIES Filed Aug; 24, 1937 /3 l 1 /3 :7 5:11: I /2 "/5 30 90 g I I 4 1 L 1 L- v INVENT R- ATTORNEY;

Patented-Jan. 14, 1941 I UNITED STATES un'rnon ormxmc "roams. nonms Alessandro Magnani, Broni, Italy, assignor to 1-. L. Smidth & o. AIS, Wnhagen, Denmark, a corporation of Denmark Application August 24, 1937, Serial No. 160,596 In Great Britain and Sweden March 3, 1937 1 Claim. (01. 92-543 form is distributed on the surface of a rotating molding ,roller having a permeable surface, through which the water is drawn off by suction.

15 As the layer of pulp'builds up on the roller, it

is shaped by a shaping roller which rotates tangentially to the molding roller and is pressed light y against the surface of the layer.

The patented process and apparatus are simple 20 and generally satisfactory, but occasionally, the drawing off by suction of the water from the layer of pulp on the surface of the molding roller results in the formation of holes through the layer.

This permits air to'leak into the interior of themolding roller so that the suction effect is reduced and the layer is not suillciently deprived of water. In addition, the thickness and surface of the layer are not uniform.

According to the present invention, the pulp 30 in fluent form is applied to the water-permeable surface of a molding roller to the interior of which suction is applied, and as the pulp builds up on the roller to produce a layer, the pulp is pressed and compacted by a calendering roller driven at 36 a higher surface speed than that of the layer. By the use of the calendering roller, the formation of holes through the fibrous layer is prevented, since, if such holes initially develop,- they are promptly closed by the troweling action of the t0, calendering roller. Moreover, the pressing and smoothing action of the calendering roller tends to close the pores in the surface of the fibrous layer so that the tube so produced has an impermeable, compact, and uniform wall. For some 45 purposes, the calenderlng may be performed in succesive stages with the calendering roller operating on the fibl'OllS layer at relatively light pressure in the preliminary operation, and pressed more firmb against the layer in the final operation. Also, in some cases, it may be desirable to treat the surface of the tube with a reagent which causes the precipitation of solid material in the surface pores of the tube, as, for example, in the case of tubes made of asbestos cement, ll treatment of the surface thereof with soapy prevented by glands ll.

water produces a precipitation of lime soap which fills the fine surface pores and thus increases the impermeability of the surface.

For a better understanding of the invention, reference may be had to the accompanying draw- 5 ing, in which Figure 1 is aplan view, with parts removed, of apparatus which may be usedin the practice of the method of the invention; and

Figure 2 is an end view of the apparatus.

The apparatus as illustrated in th'e-drawing includes a molding roller 10, the exterior shape of which is that of the tu'be'to be produced, the roller illustrated having an" enlargement H at one end corresponding to-the socket of the finished pipe. The roller is closed at its ends and it is mounted on a shaft l2 supported for rotation in bearings 13 on suitable supports It. The shaft I2 is enlarged at one end, as indicated at l5, and through the enlargement, extends a pipe I6 connected to a vacuum pump, not shown, by which suction can be applied to the interior of the roller, the leakage of air around the pipe being The roller is preferably a seamless tube formed with a multiplicity of 2 perforations through its wall and is covered by a filter cloth l8 of linen 'or the like.

Adjacent the molding roller is a calendering roller [9 mounted on the shaft 20 which is supported in bearings 2| movably mounted on the 80 support It. Means, illustrated as links 22, connected to the bearings 2| are provided for maintaining. the calendering roller l9 in tangential contact with the surface of the molding roller at a suitable pressure, and the shaft 20 is connected through a universal'ioint 23 to a'drive shaft 2-5, which is operated at a speed such that the surface speed of the calendering roller is substantially greater than that of the molding roller.

' This may be accomplished, for instance, by driv- 4o ing the shaft 24 of the calendering roller by an electric motor 29, and driving the-shaft i2 of the molding roller by an independent motor 30, the two motors being so controlled that the motor 29operates at the proper speed in relation to the speed of the motor 30 to produce the desired differential surface speed of the two rollers. The calendering roller may have a smooth surface, but is preferably formed with a series of small circum- :fer ential grooves, which may, for example, be 1 so a valve 28 by which the rate of flow from the rate from the hopper'through the discharge pipe into a bi e oi'the rollers, and suction is applied to the interior of the molding roller. A thin layer oipulpisthusappliedtothemoldingrollerand' dewatered by the withdrawal of water into the interior of the latter, the water beingdischarged through the pipe ll. As the operation proceeds, the hopper is moved back and forth along the rails 2| so as to build up a nbrous'tubmar body on the molding roller, and as the thickness'oi.

the fibrous layer increases, the calendering roller is progressively withdrawn from the molding roller untilalayerolthe desired thickneeshas been produced. The ieed otpulp is then stopped, the pressureoithecalenderingrollerlmnstthe layeriaincreased, the rotationoitherolleraccntinuing until the thickness of the fibrous layer l0 permeability oi which can he further increased by the use of the precipitating agent, as described.

I claim:

A methodoi' producing a tubular body from iibrous pulp, which comprises distributing the'puip 18 in slurry form on the surface or a rotating per meable tubular body to progressively build up' a layer of the pulp on said body, applying suction within said body to withdraw water from the slurry through the wall of said body while said to layer is being progresively built upon the body. and, throughout the building up of the layer of pulp on said body.. 0ntinuously troweling the surface or the layer simultaneously with the withdrawal of the water from the layer to consolidate 25 the layer and clone the pom formed therein by the withdrawal of the water.- said troweling being eil'ected by subjecting the surface of the layer to the rubbing and smoothing action of another surhoepreecedagainstthesiuiaceoi thelayer and positively moved in the same direction at a substantially higher speed.

almaammo MAGNANI.