Processing Tray & Spray Bar Assembly¶
1. Purpose¶
Cyanotype prints on muslin substrate (4,499 × 2,388mm) require a controlled flood wash to remove unexposed sensitizer chemistry after UV exposure. The processing tray provides the containment surface and the spray bar delivers even water distribution across the full print width. Together they form the print washing subsystem of the water system.
Design goals:
- Flood the entire print surface uniformly in a single pass (~44 seconds)
- Contain all wash water within a sealed tray — no penetration of the container floor
- Drain water to a sump for pump-out and recycling via the Brown circuit
- Single-operator use from the walkway — no stepping on the print surface
- Permanently installed — no removal required for transport mode conversion
Interactive 3D model — the processing tray, spray-bar gantry, carriages, feed manifold, and push pole. Drag to orbit, scroll to zoom.
2. Processing Tray¶
2.1 Specification¶
| Parameter | Value | Rationale |
|---|---|---|
| Material | 16-gauge (1.5mm) 304 stainless steel, #4 brushed finish | Chemically inert to ferricyanide wash water; resists pitting from citric acid pH adjustment |
| Overall footprint | 4,459 × 2,200mm (2 panels, field-bolted) | Fits inside film plane rails (X=150–4,649) with 20mm clearance per side |
| Panel size (each) | 2,229 × 2,200mm | Two equal panels, butted at midpoint with silicone gasket + bolted flange. Each panel fits through the cargo door opening (2,340 × 2,280mm) |
| Rim height | 50mm (all four sides) | Contains 6mm flood depth with margin; constrained to ≤75mm by film plane carriage clearance |
| Floor-to-rim height | 50mm | Tray sits on tapered HDPE shim strips on the container floor |
| Fall | 1:200 dual-axis (10mm over 2,200mm Yd + 11mm over 2,229mm X) toward sump | Water converges from both axes toward the sump well |
| Sump well | 150 × 100mm, 20mm deep, pressed into tray floor at low point | Collects water at lowest point; P-04 suction pickup sits in sump |
| Weight (empty) | ~116 kg (2 panels × ~58 kg) | 304 SS, 1.5mm × 4.90 m² per panel × 7.93 kg/m² per mm |
| Weight (operating, 6mm flood) | ~175 kg | Tray + ~59 kg water (6mm over the 4,459 × 2,200mm tray ≈ 59 L) |
2.2 Slope Support — Tapered HDPE Shim Strips¶
The tray's 1:200 dual-axis slope is achieved by tapered HDPE shim strips bonded to the container floor beneath the tray. No risers, no under-tray plumbing — the tray sits directly on the shims to flow the water into the bottom right for pickup by the sump pump.
| Parameter | Value |
|---|---|
| Material | HDPE flat bar, 50mm wide |
| Quantity | 5 strips running full tray depth |
| Spacing | ~1,000mm apart across tray width (X direction) |
| Profile | Tapered: ~20mm at near rim (drain end — raised so the 20mm sump well bottom rests on the container floor) → ~30mm at far rim |
| Attachment | Construction adhesive (Loctite PL Premium or equivalent) to container floor |
| Function | Creates the Yd-axis slope; X-axis slope is formed into the tray panels during fabrication (pressed crown) |
2.3 Sump Well and Pickup¶
Instead of a through-floor drain fitting, the tray has a shallow sump well pressed into the floor at the low point. P-04 draws water from the sump via a suction pickup tube — no penetration of the tray floor or the container floor.
| Parameter | Value |
|---|---|
| Sump dimensions | 150mm (X) × 100mm (Yd) × 20mm deep |
| Sump location | IBC-end corner (near rim, low point) |
| Forming | Pressed/stamped into tray panel during fabrication |
| Pickup tube | 1" HDPE dip tube, stainless foot valve with strainer screen |
| Pickup height | Tube bottom 5mm above sump floor (leaves ~0.75 L residual) |
| Suction line | 1" flexible reinforced hose, routed over near rim to P-04 |
| Pump | P-04 (Shurflo 2088, 12V DC, 3.5 GPM, 45 PSI, self-priming) |
| Discharge | P-04 → 3W-DV-02 diverter → IBC-3 (Brown recycling) or IBC-4 (Waste) |
Why sump pickup instead of a through-floor drain:
- No penetration — eliminates leak risk from a bulkhead fitting seal
- No under-tray clearance needed — tray sits flat on shim strips
- Simpler fabrication — pressed sump is cheaper and more reliable than a welded bulkhead union
- Easier to protect — no exposed plumbing beneath the tray during transport
- Field-serviceable — pickup tube lifts out for cleaning; no tools required
2.4 Containment Liner¶
A fresh 6-mil black LDPE sheet is laid over the tray surface before each session. The liner prevents direct stainless-to-print contact (avoiding metallic marks on wet cyanotype) and simplifies cleanup. Overlap the liner 50mm over the tray rims. Cut or fold the liner around the sump pickup tube.
2.5 Clearance Verification¶
| Constraint | Clearance | Status |
|---|---|---|
| Film plane carriage blocks | 90mm above tray rim (140 − 50) | Clear |
| Film plane rails at X=150 and X=4,649 | 20mm gap between tray edge and rail | Clear |
| Spray-bar carriage (rides on the raised/sloped tray floor beneath the walkway grating) | ~30mm at the worst (far-left) carriage — Ø32 wheels + 40×25 SS beam, (see Walkway Routing Sections §H-H) | Clear |
| IBCs (X=4,674+, right end zone) | Tray ends — 45mm gap | Clear |
| Pump manifold (Corridor Plumbing Panel) | Suction hose routes over near rim exterior | Clear |
2.6 Permanent Installation¶
The processing tray is permanently installed — it remains in place during both operational and transport modes. The two panels are positioned between the film plane rails, bolted together at the center flange. The P-04 suction pickup tube sits in the sump well permanently. The 50mm rim height is below all transport-mode clearance envelopes, so no removal is required for mode conversion.
3. Spray Bar Assembly — Gantry Design¶
3.1 Design Concept¶
The spray bar delivers Blue (clean) water evenly across the processing tray during print washing. The operator slides the bar along the tray (Yd direction, from film-plane side toward the pinhole wall), flooding the print surface progressively.
The beam spans 3,859mm between the inner edges of the left and right walkways, extending under the walkway grating at each end. At each end, a two-wheel carriage rolls on the processing tray floor beneath the grating. A 3/4" LDPE irrigation poly pipe clipped to the beam's inboard side face serves as the spray manifold — the supply hose terminates at a distribution manifold by the ball joint, which feeds seven irrigation tubes that barb into the poly manifold along the beam; water then exits through twenty-six barbed flat-fan nozzles that side-tap the manifold and spray down-and-in, at 150mm pitch along the beam.
Design constraints:
- Carriage plate top must clear walkway grating underside — no contact during travel
- Wheels must fit within the 50mm tray rim height, rolling on the tray floor beneath walkways
- Single-operator use — push/pull from the near walkway via telescoping pole through a 30mm slit
- Must travel 2,200mm (tray depth, near rim to far rim)
- Tray rim walls provide lateral guidance — no separate guide rails required
- Must accommodate a flexible water connection that follows the bar as it moves
3.2 Assembly Components¶
| Component | Specification | Qty | Purpose |
|---|---|---|---|
| Beam | 304 SS RHS, 40×25×3mm (laid flat), 3,859mm long (two 8 ft lengths butt-welded); ~15mm pre-camber | 1 | Low-profile structural beam; carries the side manifold |
| Side spray manifold | 3/4" LDPE irrigation poly pipe (OD 25mm, ID 19mm) | 1 | Water distribution; clipped to the beam's inboard side face |
| Flat-fan spray nozzles | Barbed saddle-tee inlet, irrigation-type, 180° fan pattern | 26 | Side-tapped into the manifold, spray down-and-in (150mm pitch) |
| Distribution manifold | 1/2" inlet → 7 barbed outlets, mounted at the ball joint | 1 | Splits the supply hose to the 7 feed tubes |
| Irrigation feed tubes | 1/4" poly/vinyl tube, manifold to beam feed points | 7 | Distribute water along the beam (~7m total) |
| Barbed feed fittings | Barbed tee, feed tube into the side manifold | 7 | Feed points (~550mm pitch) into the manifold |
| Retainer clips | SS or nylon, for 3/4" LDPE fold-back closure | 2 | Seal both ends of poly pipe (fold-back termination) |
| Acetal (Delrin) roller wheels | Ø32 × 20mm wide, Ø10 plain bore, flat tread | 4 | Low-profile, roll on tray floor beneath walkway grating (2 per carriage, 200mm Yd spacing) |
| Axle pins (4-pack) | 10mm × 60mm 304 SS axle pin, flat head | 4 (1 pack) | Wheel spindles |
| Axle retention saddle clamps (10-pack) | 304 SS, curved conduit-style saddle, 10mm, two bolt holes | 8 | Retain the wheel axles — bolted to the carriage plate underside |
| Carriage plates | 6061-T6 AL plate 5mm, wings extend in to meet beam faces | 2 | Carry wheels; captured between beam clamp plates |
| Beam clamp plates | SS, top + bottom plate (~3mm) sandwiching the 25mm RHS; countersunk underside bolts | 4 (2 per carriage) | Clamp beam to carriage plate, bolted vertically |
| Spacer blocks | 6061-T6 AL, between top & bottom clamp plates, one each side of beam | 4 | Set clamp gap to beam height so bolts grip the beam rather than bend the plates |
| Ball joint | Ø20mm SS ball, zinc socket, M12 stud, 50mm flange base | 1 | Multi-axis arm articulation on beam top face |
| Self-tapping screws | SS thread-forming, into 3mm SHS top wall (no internal access for nuts) | 4 | Fasten the ball-joint flange to the beam |
| Arm tube | 6061-T6 AL round tube, 25mm OD × 2mm wall, ~500mm | 1 | Vertical arm from ball joint to pole |
| M6 pinch bolt | SS hex bolt + nut | 1 | Clamps arm tube onto ball joint stud |
| Push pole | Telescoping aluminum pool pole, 1.2–2.4 m | 1 | Operator controls bar position from walkway |
| Flexible hose | 1/2" reinforced braided PVC, ~4 m coiled | 1 | Connects BV-02 to the distribution manifold |
| Zip ties | Nylon, 200mm | ~6 | Secure flex hose to arm tube |
3.3 Beam / Spray Pipe¶
The structural beam carries a 3/4" LDPE irrigation poly manifold clipped to its inboard side face. A 304 SS RHS (40×25×3mm, laid flat) spans 3,859mm between the inner edges of the left and right walkways.
Beam properties:
| Property | Value |
|---|---|
| Material | 304 stainless steel |
| Section | 40×25×3mm RHS, laid flat (low profile for grate clearance) |
| Internal bore | 34×19mm |
| Span | 3,859mm (X=470 to X=4,329) |
| Second moment of area (I) | 32,650mm⁴ |
| Cross-sectional area | 354mm² |
| Linear mass (beam only) | 2.83 kg/m |
| Beam mass (3,859mm) | 10.9 kg |
| Bending stiffness (EI) | 6.30×10⁹ N·mm² (≈ the former 40×40 alu beam's 7.04×10⁹ — SS modulus offsets the shallower depth) |
| Pre-camber | ~15mm up at mid-span (offsets the self-weight sag, L/257, so the beam runs flat under load) |
Sourcing: Standard 8 ft (2,438mm) lengths are widely stocked at Home Depot, Online Metals, and metals suppliers. Two 8 ft lengths are required; see §3.8 for splice joint.
Spray nozzles:
| Property | Value |
|---|---|
| Nozzle type | Flat-fan irrigation nozzle, barbed inlet |
| Number of nozzles | 26 |
| Nozzle spacing | 150mm center-to-center |
| Spray pattern | 180° flat fan |
| Manifold OD / ID | 25mm / 19mm (3/4" LDPE) |
| Manifold mounting | Clipped to the beam's inboard side face (cushioned pipe clips + the nozzle saddle-tees) |
The twenty-six nozzle saddle-tees plus the seven feed tees tap directly into the side manifold and grip it by their barb ridges. Because the manifold is external, no beam-wall drilling is needed; the tees plus cushioned pipe clips locate the manifold along the beam.
Beam ends (open):
The SS RHS ends are simply capped (welded or plug). The side 3/4" LDPE manifold terminates just outside each beam end with a standard fold-back closure: the pipe folds 180° back on itself and is secured with a stainless steel or nylon retainer clip (see Sheet 4, Detail A). The fold-back and retainer clip provide a watertight seal; the SS beam is purely structural.
- Feed points (7, ~550mm pitch): Barbed feed tees installed into the side manifold — each connects an irrigation tube from the ball-joint manifold to the poly pipe bore, distributing the supply evenly along the pipe.
- Both ends (X=470 and X=4,329): LDPE fold-back with retainer clip — fully sealed.
3.4 Wheel Carriage Assemblies¶
Each end of the beam is supported by a wheel carriage that rolls on the processing tray floor beneath the walkway grating. Two carriages (left and right), each carrying two wheels spaced 200mm apart in the Yd direction for stability against tipping.
Wheel specification:
| Property | Value |
|---|---|
| Type | Fixed (non-swivel) acetal (Delrin) wheel |
| Diameter | 32mm |
| Width | 20mm |
| Bore | 10mm |
| Load rating | Light-duty — actual load ~2.6 kg per wheel wet (a solid acetal wheel carries this easily) |
| Tread profile | Flat (rolls on the stainless tray floor, raised on the shim ramp) |
| Material | Solid acetal (Delrin), plain bore — corrosion-immune, self-lubricating on the 304 SS axle (no carbon-steel bearings for the wet wash) |
Vertical geometry (all dimensions mm above finished floor):
| Reference point | Z (mm AFF) |
|---|---|
| Container floor | 0 |
| Raised tray floor (near/low rim, on the shim ramp) — the wheels roll here | 20 |
| Bottom clamp plate (under beam) | 26–29 |
| Beam bottom | 29 |
| Wheel axle centerline | 36 |
| Carriage plate (2mm above axle) | 38–43 |
| Wheel top | 52 |
| Beam top | 54 |
| Top clamp plate | 54–57 |
| Left-walkway support arm bottom (over spray bar) | 75 |
| Walkway grating bottom | 115 |
| Walkway grating top (deck surface) | 130 |
(Full stack-up — clamp plates, carriage plate, side manifold/nozzle — is drawn on Sheet 2; the poly manifold is side-mounted per §3.3.)
Clearances:
| Interface | Gap | Notes |
|---|---|---|
| Beam bottom → tray floor | 9mm | Spray gap; pre-camber offsets the self-weight sag so the beam runs flat under load (§3.3) |
| Wheel top → left-walkway support arm bottom | 23mm | Wheels roll freely beneath the walkway structure |
| Carriage stack → walkway grating bottom | ~30mm at the worst (far-left) carriage | See §2.5 and Walkway Routing Sections §H-H |
Axle retention: Each wheel axle (10mm SS axle pin) is held by a curved 2mm 304 SS saddle strap (formed from flat bar) bolted to the underside of the carriage plate. The saddle cradles the axle pin with 1mm clearance; two bolts pass up through the saddle feet and carriage plate to lock the axle in position.
3.5 Carriage Plate Design¶
Each carriage uses a flat aluminum plate positioned 2mm above the wheel axle. The plate wings extend inward to meet the beam faces; the beam is gripped by a top and bottom clamp plate that sandwich it vertically, with the carriage plate wing captured in the same bolted stack. The beam stays at its design height.
Formed from 5mm 6061-T6 aluminum plate:
- Plate wings: Two flat sections extending from the beam faces out to the wheel axle positions. Total plate width spans both wheel positions plus 18mm overhang on each side; the outer edge is flush with the beam end.
- Center notch: The wings butt against the 40mm beam faces (no gap), so the carriage and beam read as one continuous body.
- Beam clamp: A bottom clamp plate (under the beam) and a top clamp plate (over the beam) are drawn together by bolts on each side of the beam. A solid aluminum spacer block beside each beam face fills the gap between the plates so tightening grips the beam instead of bending the plates.
- Ball joint mount: The ball joint flange is fastened to the beam top face with self-tapping screws, keeping the socket housing below grating level).
Lateral guidance: The tray rim walls (50mm high) act as lateral guides. The wheel carriages roll between the tray rim and the walkway support structure. The 200mm wheel spacing in Yd prevents significant skew.
3.6 Carriage Fabrication¶
Each carriage is built from two sub-assemblies: a carriage plate, and wheel-and-axle units retained by curved saddle clamps. The beam is then sandwiched between a top and bottom clamp plate bolted through the carriage plate. Two identical carriages are required (left end and right end of beam).
3.6.1 Carriage Plate Fabrication (2 required)¶
Each carriage plate is a flat 5mm 6061-T6 aluminum plate whose wings meet the beam faces. The plate sits 2mm above the wheel axle; the beam clamp bolts pass through it, capturing the plate between the top and bottom clamp plates.
Blank: Cut two pieces from 5mm plate, each 280mm long × 60mm wide.
| Step | Operation | Detail |
|---|---|---|
| 1 | Mark notch | Scribe the central notch so the wings butt the 40mm beam faces (outer edge flush with beam end) |
| 2 | Cut notch | Jigsaw or bandsaw the center notch from one long edge |
| 3 | Mark axle saddle positions | On each wing, mark two Ø5.5mm clearance holes (M5) per saddle clamp for axle retention |
| 4 | Mark beam clamp bolt positions | Two Ø5.5mm holes on each side of the beam, aligning with the top/bottom clamp plate bolts |
| 5 | Drill all holes | Drill press for accuracy — 8 axle saddle holes + 4 beam clamp holes per plate |
| 6 | Deburr | Remove all burrs from edges, notch, and holes |
3.6.2 Wheel Assembly (2 per carriage, 4 total)¶
Each wheel axle is retained by a curved 2mm 304 SS saddle strap (formed) bolted to the carriage plate underside. The saddle cradles the 10mm axle pin with 1mm clearance.
| Step | Operation |
|---|---|
| 1 | Place nylon wheel (32mm × 20mm, 10mm bore) in position under the carriage plate |
| 2 | Insert 10mm SS axle pin through wheel bore |
| 3 | Position the saddle clamp over the axle, feet against the plate underside |
| 4 | Insert 2× M5 bolts up through the saddle feet and carriage plate; secure with nyloc nuts on top |
| 5 | Tighten finger-tight only until all wheels are installed |
| 6 | Spin wheel by hand — confirm free rotation with no lateral wobble |
3.6.3 Carriage Assembly (2 required)¶
| Step | Operation |
|---|---|
| 1 | Place carriage plate flat on bench, notch centered |
| 2 | Install the near wheel-and-saddle unit (wheel hanging below bench edge) — finger-tight |
| 3 | Install the far wheel-and-saddle unit (200mm Yd spacing) |
| 4 | Verify 200mm wheel spacing (center-to-center, Yd direction) |
| 5 | Tighten all nyloc nuts to 4 Nm |
| 6 | Stand the carriage on a flat surface — both wheels must contact simultaneously. Shim if needed before final torque |
3.6.4 Beam Attachment¶
The carriages attach to the beam with a top + bottom clamp plate that sandwich the SHS vertically. The bottom plate sits under the beam and the top plate over it; a solid aluminum spacer block beside each beam face fills the gap so the bolts grip the beam rather than bending the plates. Four bolts per carriage pass through the top plate, spacer, carriage plate wing, and bottom plate, with nuts top and bottom.
| Step | Operation |
|---|---|
| 1 | Position the bottom clamp plate under the beam SHS, with its outer edge flush with the beam end |
| 2 | Set the carriage plate over the beam so the wings butt the beam faces |
| 3 | Place a spacer block against each beam face, between the plate wings |
| 4 | Lay the top clamp plate over the beam, aligning the bolt holes with the bottom plate |
| 5 | Pass four bolts down through top plate + spacer + carriage wing + bottom plate; thread nuts top and bottom and tighten evenly until the beam is gripped |
| 6 | Set the assembled spray bar on the processing tray floor. Confirm the top clamp plate clears the walkway grating bottom. Confirm all wheels roll freely on the tray floor |
| 7 | Push the bar through its full travel to verify it tracks straight between the tray rim walls without binding |
3.7 Structural Analysis¶
Loading (simply supported, uniform distributed load across 3,859mm span):
| Component | Linear mass (kg/m) | Linear weight (N/m) |
|---|---|---|
| Beam (304 SS, 40×25×3mm RHS) | 2.83 | 27.76 |
| LDPE side manifold (OD 25mm, ID 19mm, wall 3mm) | 0.193 | 1.89 |
| Water in manifold (19mm ID bore) | 0.283 | 2.78 |
| Total UDL | 3.306 | 32.43 |
Water volume in the manifold: π × 9.5² × 3,859 = 1.09 L (1.09 kg), carried in the LDPE manifold, not the beam.
Deflection — δ = 5wL⁴ / 384EI, E = 193,000 MPa (304 SS), I = 32,650mm⁴:
| Condition | w (N/m) | δ center (mm) | Span ratio |
|---|---|---|---|
| Dry (beam only) | 27.76 | 12.7 | L/304 |
| Dry (beam + manifold) | 29.66 | 13.6 | L/284 |
| Wet (beam + manifold + water) | 32.43 | 14.9 | L/259 |
The 40×25 SS section has almost the same bending stiffness as the former 40×40 alu beam (EI ≈ 6.30 vs 7.04×10⁹ N·mm²), but SS's higher density roughly doubles the self-weight, so the raw wet deflection is ~15mm (L/259) rather than the former ~7mm. This is a beam-flatness matter only — it does not affect the carriage-to-grate clearance (deflection is zero at the supports, where the ~30mm clearance is measured), and the sagged midspan beam bottom still clears the thin wash film.
Pre-camber (required): Fabricate the beam with ~15mm upward pre-camber at midspan so it deflects to flat under full water load. Method: hold the two halves at a shallow upward angle in a jig while butt-welding the midspan joint (§3.8). With ~9mm beam-to-floor clearance at the supports and the camber applied, the beam runs level under load.
Weight summary:
| Component | Mass (kg) |
|---|---|
| Beam (40×25×3mm 304 SS × 3,859mm) | 10.9 |
| LDPE manifold (OD 25mm × 3,859mm) | 0.74 |
| Water in manifold | 1.09 |
| Carriage plates (2×) | 0.35 |
| Wheel assemblies (4× Ø32 wheel + axle + 8 saddle clamps) | 0.45 |
| Nozzles (26×) + feed manifold/tubes/fittings | 0.50 |
| Hardware (bolts, clips, clamp plates) | 0.35 |
| Dry total | ~13.3 kg |
| Wet total (operating) | ~14.4 kg |
Per wheel load (wet): 14.4 / 4 = 3.6 kg — well within any small nylon wheel's rating. The +6.3 kg beam-mass increase (vs the former alu beam) is carried into the walkway/CG budget in Weight Distribution.
3.8 Beam Splice Joint¶
Two 8 ft (2,438mm) SS RHS lengths are butt-welded at midspan (304 SS is readily TIG-welded):
- Joint: square butt weld, full-penetration, ground flush; the ~15mm camber is set in the welding jig
- Finish: passivate the weld zone (citric or nitric) to restore corrosion resistance in the wash environment
- Location: Midspan (1,930mm from each end), the point of maximum moment — a full-penetration weld develops the full section, so the splice is not the weak point.
Alternative: Source a single 16 ft or 20 ft length by special order to eliminate the splice (and set the camber over the full length).
3.9 Flow Analysis¶
| Parameter | Value |
|---|---|
| Supply pump | P-01 (Shurflo 2088), 3.5 GPM at 45 PSI |
| Pipe bore (LDPE) | 19mm ID = 283.5mm² |
| Feed points (manifold) | 7 (~550mm pitch) — 0.5 GPM per feed tube |
| Spray nozzles | 26 × flat-fan irrigation nozzles |
| Flow per nozzle | 0.135 GPM (0.51 L/min) |
Feeding the poly pipe at seven points (~550mm pitch) from the ball-joint manifold — rather than a single center feed — keeps the supply pressure uniform along the pipe, so each of the 26 nozzles sees nearly the same flow regardless of its distance from the inlet. The 19mm bore provides adequate flow capacity at 3.5 GPM. Each irrigation nozzle delivers a 180° flat fan pattern; at 150mm pitch the fans overlap heavily, giving near-continuous wash coverage along the 3,859mm beam span.
3.10 Water Connection¶
BV-02 (1/2" ball valve, Blue supply isolation) is mounted on the pinhole wall (Yd=0) at X=2,399mm (pinhole centerline), Z=900mm — waist height from the walkway deck. A 1/2" HDPE riser runs from the Blue supply trunk up to BV-02. A 4 m length of 1/2" reinforced braided PVC hose connects from BV-02 down to the distribution manifold at the ball joint. The hose coils when the bar is near the pinhole wall and extends as the bar is pushed toward the far wall. The hose trails along the near tray rim, staying clear of the print surface.
Supply path: P-01 → ACC-01 → rigid 1/2" HDPE pipe along pinhole wall → BV-02 → coiled flexible hose → manifold → 7 irrigation tubes → poly pipe bore → 26× spray nozzles.
3.11 Walkway Slit¶
The operator controls the spray bar position from the near walkway using a telescoping aluminum pool pole (1.2–2.4 m). The pole passes through a 30mm wide slit cut into the walkway grating at the beam centerline. A matching slit is cut into the far walkway grating at the same X position. The slit positions are shown on the walkway plan view.
3.12 Ball Joint and Arm¶
A Ø20mm stainless steel ball joint on the beam top face provides multi-axis articulation between the beam and the operator's pole. The ball sits in a zinc socket housing on a 50mm flange base. The flange is fastened to the beam top with four self-tapping (thread-forming) stainless screws driven into the 3mm SHS top wall — the beam is sealed, so there is no internal access to tighten nuts. Nothing overhangs the ball, so the arm articulates freely in every direction.
A 25mm OD × 2mm wall aluminum round tube (~500mm long) connects from the ball joint stud to the telescoping pole. An M6 pinch bolt clamps the arm tube onto the stud. The 1/2" flexible hose is zip-tied to the arm tube at ~200mm intervals.
4. Operation¶
The step-by-step spray bar setup, wash pass procedure, Brown water recycling passes, and storage are documented in the Operating Manual — Phase 4: Development.
5. Engineering Drawings¶
Seven detail sheets cover the spray bar assembly and processing tray:
| Sheet | Title | Content |
|---|---|---|
| 1 | Gantry Elevation | X-Z section from film plane (4× vert exag) — beam, BV-02, pole, walkway slit, operator silhouette |
| 2 | Cross Section — Beam Assembly | Yd-Z composite at 1:1 — wheels, carriage plate, beam clamp plates, saddle clamps, ball joint, arm, hose |
| 3 | Plan View | Container floor plan — walkways, slit positions, beam travel range |
| 4 | Detail A — Beam End | Longitudinal section at 2:1 — LDPE fold-back end closure with retainer clip |
| 5 | Detail C — Wheel Attachment | Section along axle at 4:1 — carriage plate, nylon wheel, axle pin, saddle clamp |
| 6 | Detail D — Wheel Plan | Plan view of carriage — beam, carriage plate, beam clamp plate, saddle clamps, wheels |
| 7 | Detail B — Manifold Feed | Longitudinal section at 2:1 — manifold-fed barbed feed connection (typ. ×7) and nozzle connection details |
Additional processing tray drainage detail is shown in the water system drawings (sheets 3–4: tray drainage plan and sump cross-section).
6. Parts List¶
6.1 Processing Tray¶
| Item | Spec | Qty | Supplier | Est. cost |
|---|---|---|---|---|
| 304 SS sheet, 16-gauge (1.5mm), #4 brushed | 2,229 × 2,200mm panels | 2 ea | Online Metals | $720–$1,000 |
| Fabrication (cut, brake, weld, press sump) | Two panels with center flange + sump well | 1 lot | Local sheet metal | $450–$850 |
| HDPE flat bar, 50mm wide | Tapered shim strips, 2,200mm each | 5 ea | Online Metals | $40–$75 |
| Loctite PL Premium construction adhesive | Shim-to-floor bond | 2 tube | Home Depot | $15 |
| 1" SS foot valve with strainer screen | Sump pickup tube | 1 ea | Amazon | $20 |
| 1" reinforced suction hose, 6 ft | Pickup tube to P-04 | 1 ea | Amazon | $15 |
| Silicone gasket strip | Center flange seal | 1 ea | McMaster-Carr | $20 |
| M6 SS hex bolts + flange nuts | Panel flange bolts | 12 ea | McMaster-Carr | $12 |
| 6-mil black LDPE sheet, 10 ft × 8 ft | Containment liner (consumable, per session) | 1 ea | Home Depot | $8 |
| Tray total | $1,300–$2,015 |
6.2 Spray Bar Assembly¶
| Item | Spec | Qty | Supplier | Est. cost |
|---|---|---|---|---|
| 304 SS RHS 40×25×3mm, 8 ft * | 40×25×3mm rectangular tube, laid flat (low profile); 2 sticks butt-welded to span | 2 ea | Online Metals | $96–$144 |
| 6061-T6 AL plate 3/16" (5mm) | Carriage plates + spacer blocks (~300 × 500mm sheet) | 1 ea | Online Metals | $16–$28 |
| 3/4" LDPE irrigation poly pipe, 15 ft | Side-mounted spray manifold, clipped to the beam's inboard face (OD 25mm, ID 19mm) | 1 ea | Amazon | $10 |
| Flat-fan irrigation spray nozzles, barbed | 180° fan pattern; side-tapped into the poly manifold, spray down-and-in | 26 ea | Amazon | $30–$50 |
| Distribution manifold, 1/2" → 7 barb outlets | Mounted at ball joint, splits feed to tubes | 1 ea | Amazon | $12 |
| 1/4" irrigation poly tube | Manifold to beam feed points (~7m total) | 1 ea | Amazon | $6 |
| Barbed tees, tube into the side poly manifold | Feed tube to the side poly manifold, 7 feed points | 7 ea | Amazon | $10 |
| SS/nylon retainer clips for 3/4" LDPE | Fold-back end closures | 2 ea | Amazon | $4 |
| Acetal (Delrin) roller wheel, Ø32 × 20mm, Ø10 plain bore | Solid acetal (Delrin), flat tread, plain bore — corrosion-immune + self-lubricating on the Ø10 304 SS axle (no carbon-steel ball bearings; the ferricyanide/citric wash rules those out). Turned from acetal rod or an equivalent POM plain-bore roller. Light-duty (~2.6 kg/wheel wet); 2 per carriage, low-profile for grate clearance. | 4 ea | McMaster-Carr | $12–$20 |
| 1/2" barb × 1/2" hose barb, brass | Flex hose to manifold inlet | 1 ea | Amazon | $4 |
| Telescoping aluminum pool pole, 4–8 ft | Standard pool skimmer handle | 1 ea | Amazon | $15 |
| 1/2" reinforced braided PVC hose, 15 ft | BV-02 to beam feed (4 m coiled) | 1 ea | Amazon | $15 |
| 10mm × 60mm 304 SS axle pin (4-pack) | Wheel axle pins | 1 pack | Amazon | $5 |
| Formed 2mm 304 SS saddle clamp (axle retainer) | Axle retention — 2mm 304 SS flat bar formed to a saddle over the Ø10 axle (1mm cradle clearance), 2 bolt feet through the carriage plate. A stamped conduit saddle clamp is only ~0.5mm — too thin for a rolling-carriage axle retainer. Alt: 304 SS + EPDM Adel loop clamp ~3/8–7/16" ID. | 8 ea | McMaster-Carr | $10 |
| M6×20 SS bolts + nyloc nuts | Carriage plate, beam clamp, saddle fasteners | 16 ea | McMaster-Carr | $7 |
| Self-tapping SS screws (8-pack) | Ball-joint flange to beam top wall | 4 ea | McMaster-Carr | $5 |
| Ø20mm ball joint, zinc socket, M12 stud | Multi-axis arm articulation | 1 ea | Amazon | $12 |
| SS beam clamp plates (top + bottom) + spacers (25mm) | Beam to carriage plate (sandwich, countersunk underside bolts) | 4 ea | McMaster-Carr | $10 |
| 6061-T6 AL round tube 25mm OD × 2mm wall, 500mm | Arm tube | 1 ea | Online Metals | $6 |
| M6 SS hex bolt + nut | Pinch bolt for arm tube | 1 ea | McMaster-Carr | $1 |
| Nylon zip ties, 200mm | Hose to arm tube | 6 ea | Amazon | $1 |
| Spray total | $287–$375 |
6.3 Combined Total¶
| Subsystem | Cost Range |
|---|---|
| Processing tray | $1,300–$2,015 |
| Spray bar assembly | $287–$375 |
| Total | $1,587–$2,390 |
7. Maintenance¶
| Task | Interval | Procedure |
|---|---|---|
| Tray wipe-down | After each session | Remove LDPE liner, wipe tray with damp cloth, inspect sump for debris |
| Sump pickup clean | Monthly | Lift pickup tube, rinse strainer screen, check foot valve seal |
| Spray nozzles | Monthly | Flush beam bore with clean water; remove and soak nozzles in vinegar to clear mineral deposits |
| Wheel inspection | Quarterly | Check for flat spots, debris in tread, axle pin retention |
| Hose inspection | Quarterly | Check for kinks, abrasion, fitting tightness |
| Tray panel flange | Annually | Inspect silicone gasket, retighten flange bolts if needed |
8. Source References¶
- Shurflo 2088 Series datasheet — SHURflo / Pentair. Performance curves, priming capability, electrical specifications.
- 304 stainless steel rectangular tube — Online Metals / Metal Supermarkets catalog (spray-bar beam). Mechanical properties per ASTM A554. Aluminum plate/pole per 6061-T6 (ASTM B221).
- 304 stainless steel sheet — AK Steel Product Data Bulletin. Chemical resistance, mechanical properties per ASTM A240.
- HDPE chemical resistance — Chevron Phillips Chemical Company. Flat bar available from McMaster-Carr (catalog #8619K).
- Cyanotype chemistry — Ware, Mike. Cyanotype: The History, Science & Art of Photographic Printing in Prussian Blue (2014). Wash water composition and pH requirements.