The penstock sluice valve wedge body is the closing member that seals against the frame seat in a channel or wall-mounted penstock, carrying the stem nut pocket, the sealing faces and the guide shoes that keep it tracking under head. Sand-cast wedges arrive with porosity at the sealing face and a stem nut pocket that is out of position, so the wedge cocks in the frame and leaks under full head, and welded fabrications distort across the face so the seal never beds in. Ningbo Ruican casts the wedge in one piece with the nut pocket cored and the rib structure integral, then machines the sealing faces flat and parallel.
Specifications
| Parameter | Specification |
|---|---|
| Casting process | Silica sol lost wax investment casting; water glass route for large section penstock wedges |
| Material options | EN-GJS-500-7 ductile iron, AISI 316L / CF3M, duplex 2205 on request |
| Dimensional tolerance (ISO 8062-3 CT grade) | CT6 as cast; CT5 machined on sealing faces, stem nut pocket and guide shoes |
| Machining | 5-axis CNC milling of the sealing faces, boring of the stem nut pocket, milling of the guide shoe pads |
| Surface finish (Ra) | Ra 3.2 um as cast; Ra 1.6 um machined on sealing faces and guide shoe pads |
| Pressure class or size range | DN200 to DN1200 (8 in to 48 in) penstock wedges; head pressures to 10 m water column |
| Typical lead time | Tooling 5-6 weeks; first article 3-4 weeks after tooling; production 6-8 weeks |
Key features
- Sealing faces machined flat and parallel within 0.10 mm over the full face, so the wedge beds onto the frame seat evenly instead of leaking at one corner.
- Stem nut pocket cored and then bored concentric to the wedge centreline within 0.08 mm, removing the cocking and guide shoe wear caused by an off-centre nut.
- Integral rib structure cast in place removes four internal stiffener welds and the straightening operation that follows them on fabricated wedges.
- EN-GJS-500-7 gives 500 MPa minimum tensile strength and 7 percent minimum elongation, carrying penstock head load without the brittle behaviour of grey iron.
- 316L wedge option gives a PREN of about 24 for treated sewage, seawater outfall and chemically dosed channels where ductile iron needs coating or replacement.
- Wall thickness held uniform to +/-0.8 mm across the face and rib section, avoiding the local thin section that sand-cast wedges show after fettling and that flexes under head.
- Guide shoe pads machined in the same datumed setup as the sealing faces, keeping wedge travel square and reducing stem thrust over the full opening stroke.
Applications
- Moreover, Municipal wastewater treatment inlet works, storm tanks and final effluent channels.
- Irrigation district canal offtakes and penstock flow control structures.
- Flood defence and tidal outfall penstocks on coastal drainage networks.
- Hydroelectric and raw water intake screening and isolation channels.
- Pulp and paper mill effluent channels with fibrous and abrasive solids.
- Desalination and power station cooling water intake and discharge penstocks.
Quality & compliance
Penstock wedges are produced under IATF 16949 and ISO 9001 process control, with EN-GJS-500-7 and AISI 316L supplied and inspected to the buyer’s specified material standard and released with EN 10204 3.1 certification covering chemistry, tensile properties, nodularity for ductile iron and heat identity. Heat lot traceability links each wedge to the melt record and the machining batch. Moreover, PPAP and FAIR packages are available. Seat leakage and hydrostatic testing follow the head pressure, duration and allowable leakage you specify, and dye penetrant or radiographic examination is supplied to your specified acceptance level and reference radiograph plate. Generally, dimensional reports covering face flatness, parallelism and nut pocket position are issued with every lot.
FAQ
Can you work from a sample wedge or an existing frame drawing?
Yes. Send the sample wedge or the frame drawing and we scan or model the mating geometry, then issue a wedge drawing for approval. Face flatness, nut pocket position and guide shoe dimensions are confirmed with you because they govern how the wedge beds into the frame. Additionally, your sample is retained as the reference part for the program.
Do you supply radiography, and to what acceptance level?
We supply radiographic examination of the nut pocket and rib junction together with dye penetrant on all machined faces, both to the acceptance level and reference radiograph plates you specify. We follow your acceptance criteria and report findings with the lot rather than applying an internal standard, so your reviewer works to the same criteria every release.
What is the minimum order quantity?
Pilot quantities from 10 pieces are accepted on a single tooling set, with prototype runs below that quoted case by case. As your volume grows we move to multi-cavity tooling to reduce piece cost, and tooling is maintained, identified and stored at no charge between releases so replacements for the installed base stay available.
Can you machine and pressure test fully in-house?
Yes. Face milling, nut pocket boring and guide shoe pad machining run on in-house 5-axis and CNC equipment, and seat leakage testing is performed in-house to the head pressure and allowable leakage you specify. Results are reported per lot, and keeping machining and testing in one facility means one control plan holds every datum on the wedge.
Which material suits our channel, ductile iron or 316L?
EN-GJS-500-7 is the standard choice for municipal water, irrigation and storm channels, giving 500 MPa tensile strength at a low material cost and accepting a coating system. In general, AISI 316L suits treated sewage, seawater outfalls and chemically dosed channels where chloride pitting would attack iron. We review the medium, head and coating plan with you before recommending.
CTA
Send your penstock sluice valve wedge drawing, frame drawing or sample for a DFM review, flatness study and quotation. Contact Wendy She – sales@cnsandcasting.com – WhatsApp +86-13777124360, or visit https://cnsandcasting.com to start your penstock program with Ningbo Ruican.
