我司生产的弹簧预紧装柱机分为内径30mm，50mm，大小均可定制，
装柱完成后可保持柱内恒压，填料不塌陷。
The spring pretensioner column machine produced by our company is divided into inner diameter of 30mm, 50mm, and the size can be customized.
After the column is loaded, the constant pressure in the column can be maintained, and the packing material will not collapse.
