A.2倍 B.加20mm C.5倍 D.加50mm
A.吸入管上應(yīng)裝閘閥、止回閥和底閥 B.壓出管上應(yīng)裝止回閥、閘閥和底閥 C.吸入管上應(yīng)裝底閥,壓出管上應(yīng)裝止回閥和閘閥 D.吸入管上應(yīng)裝止回閥和閘閥,壓出管上應(yīng)裝底閥
A.20-27 B.23-27 C.27-30 D.30-33