Chinese suppliers for boilers, compressed air and hydraulics

Checked October 2026 on the investor's budget question. New
docs/suppliers/china-utilities.md: boiler makers (ZOZEN, Sitong,
Fangkuai, Taiguo, Yuanda, Yongxing, Taishan, Nobeth) with fit for 500
kg/h at 1.25 MPa, claimed certificates, Thai references and listing
prices; the Thai rules for an imported boiler (MR and MOI notification
B.E. 2549: ASME/JIS/EN or equivalent, certification-body verification,
once-through relief does not reach 10.5 bar, licensed controller, annual
inspection); compressor makers with Thai offices (Kaishan, Denair) and
sizing; hydraulic pump sets and accumulators (Huade, Yuci, Hengli, WMD,
Renowell, Inovance, NXQ makers), the shared-ring-main risks and Thai HPU
builders; duty and freight; open RFQs.

Result: about 2M THB at the midpoint (~2.5M with contingency), ~1 % of
the 216M target, mostly the boilers; Newbilt aggregates stay Newbilt's.
total-investment notes it and lists the uncosted central hydraulic
plant; utilities CSV gets the Chinese candidates and route estimates;
backlinks from equipment-suppliers, pressing-line, README.

docs/suppliers/equipment-suppliers.md

@@ -182,6 +182,10 @@ feeds the colour/splatter work the semi-automatic line is meant to serve.
   precedent)
 - Water treatment for boiler feed and closed-loop cooling
 - Compressed air generation
+- Chinese suppliers for the steam boilers, compressed air and the
+  central hydraulic plant (checked October 2026: makers, published
+  prices, Thai offices, and what Thai law asks of an imported boiler) are
+  in [Chinese suppliers](china-utilities.md)
 - Hydraulic oil (~200 L, ISO VG 32/46 HLP per DIN 51524-2, per Newbilt spec)
 - Whole-factory HVAC: continuous temperature (20-26 °C), humidity (35-60%
   RH), and PM control with zoned filtration tiers, sized for northern