3. Hunting laying because the linear expansion coefficient of polyethylene pipe ten times higher than the metal pipe, so the temperature changes cf. active. To prevent the occurrence of tensile stress, polyethylene should be used in hunting laying. 4. Laying exceptionally lots means lots exceptionally crossing railways, rivers, bridges, and other sites important journey. Because polyethylene pipe is relatively easier to suffer in terms of man-made damage to the pipe, in principle, should not use these lots polyethylene pipe, if must use polyethylene pipe, you should increase the casing or use other protective measures. Furthermore, PE pipes shall not pass through buildings and large-scale structures from below; and shall accumulation of flammable, explosive materials and having a corrosive liquid crossing below; must not be laid with other pipes or cables in the same ditch. PE gas pipeline should not be directly introduced within the building or attached directly to the introduction of a regulator in the wall inside the building when the direct introduction with PE gas pipeline, through the foundation or exterior walls and the floor, some of the PE gas pipe is necessary to choose a hard Casing maintenance. Home Previous 1 Next Last page about the hot words Find: Water Conservancy civil engineering thesis papers oil pipeline gas energy power polyethylene pipe stress accounting machine paper economically reasonable; 9 e * _2 @ "J. b # A # E6 l) [( 5) has a construction conditions .- H6 W / s' S1 e; d # {# Q Second appearance disposal 9 L + ~ m: j / i1 steel exterior Rust grades and preparation grades should be based on GB8923 "steel exterior rust before painting! Ratings and rust rating "typical boilerplate photo cf. conclude see 5.* 5 l5 A." I) {6 Z * p2 steel appearance Rust grades and preparation after the quality level:. g # D # w5 C & w9 S $ I; M (1) the appearance of corrosion of steel grades, divided into the following 级 4 A level - all covered with scales and almost no rust steel exterior; 1 [# o3 _0 (h8 Q8 e9 jB level - has seizures corrosion. and some scales have been falling steel exterior; & {; ^ 0 w8 E6 Up) gC level - the scale has been due to corrosion and can be scraped off or, and there are a few pitting steel exterior; $ C 'R $ S6 h3 _)] 5 n I + JD level - the scale is all due to corrosion and peeling, pitting and has been widely episodes steel appearance. 7 F $ C 'X7 x0 g S:. C: A, {6 t (2) the appearance of rust steel grades, divided into the following five::! `& E & Z / L z, + E St2- complete craft and power stuff no visible rust steel exterior grease and grime, and no attachment is not strong attachments oxide, rust and paint layer. ! Z +] 'H; I $ i: @ 2 Vw St3- very complete craft and power rust steel exterior with no visible grease and grime, and no adhesion is not strong oxidation, rust and paint and other fixtures, rust more complete than St2, exposing some of the appearance of the substrate should have a metallic luster. 3 R 'P "x & b6 g Sa1- mild eruption or projectile rust steel exterior with no visible grease and grime, and no adhesion is not strong oxidation, rust and paint and other attachments. 3 M0 H, p. M - {* j / @ Sa2- full eruption or projectile steel exterior with no visible rust oils and grime and oxidation, rust and paint coatings and other fixtures have a foundation to eradicate its residue should be a strong attachment . $ _ $} "z 'K & o5 X + DS2.5- very full eruption or projectile rust steel exterior grease, dirt, scale, rust and paint and other coatings no visible attachments, any residual traces of warehouse should only a thin stain or strip of electricity. g0 L # C $ a8 w # i9 I% j # y + f three ground equipment and pipeline corrosion coating total thickness shall meet the following rules. # Rs +] "^ GJ. C0 M &`, ^ 8 Y see 4.2.114 unit μ m 2 B! Q9 j6 2 B% of the total extent of corrosion coating dry film thickness U important parts or repair difficult parts of the indoor-outdoor '{8 I # d * v / {(T3 [- t + s1 h (h ≥ 200 ≥ 250 highly corrosive painting number increased from 1 to 2 moderate corrosion weak corrosion ≥ 150 ≥ 200 ≥ 100 ≥ 1203 k2 h- s4 F6 X: J3 R7 @ 8 Y four exterior paint demand for steel rust grades in the following table:; l% G * T 'S / h' [/ E5 T4 R primer species rank highly corrosive medium rust corrosion weak corrosion * C / !! D # Y (x; `1 p; g phenolic resin primer [e% U0 U * vh% Sa2.5" N # x2 O * S% w & D / g% [# u4 I9 Z # C # c2 F: `" L9% VSt32 _ o. "p6 R * C5 p8 T3 q $ V + ia; d6 {/ q 'N (_ / C St3 - \ T @; G * e *] asphalt primer' q # j $ U 'e2 U9 f% tSa2 or St3! L, u. U0 V) K. ^! h alkyd primer "g * z1 f3] 8 @ (R Sa2.5 6 n +]' p3 V # j3 V0 u ! / `perchlorethylene primer g: M # E6 C3 g9 D, v ^ + s Sa2.5, S; y # T3 & d; z & {+ Y2 k 3 O P / k) if, o8]!: \ 4 n # N: x-- + P * C. Q "f, m0 m6 f, A9 H & V5 T; p5 J4 C * u 'V B, M9 U. g # K K% h-en-phosphate primer! . l A (H4 L3 j, b- P - * R $ a:. Z6 h2 O2 ^ / ~ # T4 bf3 m _ Ring 6 v8 {/ n & _0 s3 v $ ~ - O6 D & n (F oxygen asphalt. Primer &; @ 9 YU1 j * \: kSt3 $ h (~ 8 ^) h; K: t / ~ 9 W3 a St3 + h0 H & s0 `{epoxy primer 5 \ * yW3 H" [- o1 ` Q8 j (E & S "m $ |) m0 b * L; q1 O8 U - 0 G:.. b D / w7 N polyurethane anti-corrosion primer y3] & S7 g1 S (v5 Y: | / p -" Y5 j + B: X1 a9 t $} have% q3 t (v9 e, T (C silicone heat-resistant primer 5 \ + m "P1 q + ^ 9 -, t * J0 e6 T. pOF% s Sa2.5 $ S) c / C $ i, F5 `'X & x * iSa2.5 2 H% q! A. M9 C2 A) A3 kw9 J CSM primer 7 g! x (C9 K + B (hSa2. ! 5 - v4 V1 / v "\ 3 B - $ S% J8]: Y5 z / L + F- gd5 F" d-chloro-2 X L \) C4 K (v0 H # h rubber primer 'd' h0 P & P7 K "] & J4 {$ m- o-} - (] (] 6 H (JF3 x1 a% n0 P No 3 Q,} 8 W (k 'R machine zinc-rich primer" u & G (A1 Z4 W2 Z-- + U * _. \ & G0 d! i4 k * h8 W.] $ Q (d4 G *]% F five buried disposal of equipment and piping exterior rust rating should be St3 level. # Q $ e (sk $ k;. V devices and six buried pipeline corrosion level, should determine based on soil corrosion rating (5.3.16) & G4 O2 B, P)] S% R 'N' d soil soil erosion Nature corrosion rating - O. | 8 P1 N3 N "Q; o1} corrosion resistance rating (Ωm) salt content (mass ratio%) water content (mass ratio%) current density (mA / cm) PH value, ! l3 q G $ k: H & y strong 2 J% & ["h b * ~ 3 l / u1 h3 x +} <50 4 m8 X6 T 'x; b / g6 r> 0.75 * @% T- we are! do all kinds of integrated business management consulting business management consulting organization Contact: Miss Hao Mobile: 13851787257 Telephone and Fax: 025-83619622 E-mail: 980837454@QQ.Com QQ: 1445404680 Company website: http: //www.sjzxnj.com / Address: Qixia District and Yan Jinhua Road, Building 1602 Room 289