| 摘要 |
<p>1,243,218. Cleaning gas filter elements. SLICK INDUSTRIAL CO. 22 July, 1968 [9 Feb., 1968], No. 34822/68. Heading B1T. The filter-cleaning process of Specification 1,089,032 is modified in that the number of back-pulses in any one series is five or six. Reference has been directed by the Comptroller to Specifications 812,244 and 1,089,032.</p> |
