???? ??????? Dn500 20 - ????? ?????? ????? ?????? ??????

???? ??????? Dn500 20 ?????? ?? ???? Shijiazhuang Deye Piping Industries Co.,Ltd. ?? ???? ????? ???? ?????? ?????? ???? ?????? ?????????. ?? ????? ??? ?????? ?????? ?? ???? ??????? ?? ??????? ?? ???? ????????? ??? ???? ??????? ?????? ??????? ?????? ?? ??????? ??? ?????? ???????? ???? ?????? ??????? ????? ??????? ??? ?? ????? ???? ??????? ??? ????? ???? ????? ????? ??????? ???????? ??? ????? ???? ????? ??????? ???????? ??????. ??? ????? ????? ??? ?????? ?????? ??? ???? ?????? ??? ????? ?????? ????? ?????? ?? ??????? ???????? ???? ??????? Dn500 20 ????? ????????? ?? ?????? ????? ?? ????????? ??? ?? ??? ?????????????? ?????? ?????? ??????? ?????? ?????? ??????. ??? ?????? ?? ??????? ????? ?????? ?????? ??????? ??????? ???????. ???? ????? ??????? ??????? ???????? ???? ???? ??????? ??? ????? ?????????? ???? ?????? ??? ????? ???? ?????? ?? ??? ??????? ????????? ?????? ?? ??????. ????? Shijiazhuang Deye Piping Industries Co.,Ltd. ???????? ????? ?????? ???? ???? ???????? ????????