1850.] 



THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



13 



Tlie process of manufacturing pipes according; to this invention 

 is therefore as follows: — The clay, as it is forced through the die 

 in tlie form of a pipe, slips over the mandril a. The length of 



a- 



Fig. I. 



pipe required is then cut off, and afterwards drawn by the motion 

 of the rollers over the end of the mandril, wliereby the particles 

 of matter forming the pipe become compressed or consolidated to 

 such an extent, that when baked in the usual way they have been 

 found, by repeated e.xperiments, to be upwards of 75 per cent, 

 stronger than pipes made from the same clay, but manufactured in 

 the ordinary way; besides being more regular in their structure, 

 and in every respect better finished. 



Fig. 2. 



It will be seen from the above that the pipes are compressed 

 immediately after passing through the die. This will, however, 

 depend upon the nature and consistency of the clay, and state of 

 the weather; for in some cases it may perhaps be desirable to let 

 them stand in a dry place for two or three days previous to being 

 rolled, which w ill entirely depend upon circumstances, and must 

 be left in some measure to the judgment of the workmen: It 

 will also be seen, with regard to pipes of small diameter, that the 

 rolling machine would do a greater amount of work than a pipe 

 machine having but one die. Pipes mav therefore be made in a 

 separate machine, having any required number of dies, and after- 

 wards rolled. For this purpose, the specification describes a modi- 

 fication of the above machine, to be used for the purpose of com- 

 pressing only. 



In cases where the pipe is required to have a taper hole, the 

 inventor employs a mandril made taper at the point, the mandril 



being gradually withdrawn by a screw or other suitable means, 

 during the time tlie pipe is passing between the rollers. 



Fig. 3. 



When the article to be compressed is not of a circular form, 

 two, three, or more rollers may be employed, as the nature of the 

 case may require (see fig. 3); "which show's the form, mode of ar- 

 ranging and driving three rollers for compressing an oval pipe. 



Fig. 4. 



Fig. 4 shows the form, mode of arranging and driving three rollers 

 for compressing a stairs' tread or step; the rollers o, and ft, may, 

 in this case, be engraved with any suitable device, or pattern, 

 which will be impressed on the top side and front of the step, as 



Fig. 5. 



shown at fig. 5, which represents an isometrical view of a step 

 manufactured according to this invention. 



