Mermade 39" x 50" Corner Outlet (Keene-Bowser Replacement), Cover Only

The Mer-Made 39" × 50" Corner Outlet (Keene-Bowser Replacement) — Cover Only (cataloged under Part # 775-COVER / VFC-3950-CO) is the tailored replacement synthetic fabric filter envelope engineered to re-cover existing bare leaf cores in legacy Keene-Bowser (Bowser-Briggs / Keene Corporation) commercial vacuum DE pits utilizing corner-pickup manifold headers.

Unlike center- or offset-bottom covers, this envelope features an asymmetrically positioned, reinforced cutout collar located at the lower bottom corner junction (where the horizontal bottom edge meets the vertical side edge). It includes only the fabric jacket, corner-spud opening, top closure system, and paired replacement compression sealing gaskets. It is specified when the internal drainage grid and rigid PVC/CPVC border framing remain structurally sound, but the fabric has blinded from mineral scaling, calcified DE, or body oils, or has suffered physical tears from repeated backwash cycles.

Technical Specifications & Scope of Delivery

Material Properties & Chemical Tolerances

• Chlorine & Saline Compatibility: Virgin polypropylene fibers resist chemical degradation, rot, and hydrolysis under continuous exposure to high free chlorine residuals, shock hyperchlorination treatments, and saline electrolytic water (2,500 to 5,000+ ppm NaCl).

• Acid Descaling Resilience: Tolerates seasonal restorative wash baths using dilute muriatic (hydrochloric) or citric acid solutions to dissolve embedded calcium carbonate crust and mineral scaling without deteriorating seam threads or corner reinforcing stitching.

• Cake Retention & Release: The monofilament weave structure retains standard DE powder and perlite grades without bleed-through during initial pump startup, while facilitating clean cake release during manual hose-down or backwash cycles.

Physical Dimensions & Weight Estimates

• Individual Cover Net Weight: Approximately 1.40 to 1.90 lbs (0.64 to 0.86 kg).

• Single Boxed Cover Shipping Weight: Approximately 2.80 to 4.20 lbs (1.27 to 1.91 kg) in a compact corrugated box.

• Master Carton / Multi-Pack (6 to 12 Covers): Approximately 13 to 25 lbs (5.9 to 11.3 kg).

• Full Vault Overhaul Pack (20 to 30 Covers): Approximately 33 to 54 lbs (15.0 to 24.5 kg).

Field Re-Covering & Tensioning Steps

1. Verify Handing Before Installation: Confirm whether the replacement cover corresponds to a left-hand or right-hand corner drop stem. Because the corner cutout is asymmetric, attempting to install the wrong orientation will place the top closure on the wrong side relative to adjacent frames.

2. Strip Old Jacket & Inspect Frame: Remove the spent leaf from the pit, open the top closure, peel off the spent cover, and discard the compressed felt collar. Pressure-wash the bare polypropylene drainage grid and inspect the corner weld joint for cracks or burrs that could snag the new fabric.

3. Sleeve the Frame: Slide the replacement envelope down over the 50" height of the frame, guiding the corner opening over the protruding corner discharge spud.

4. Seat the Corner Cutout: Stretch the reinforced collar cutout snugly around the base of the corner hub until seated flush against the molded locating shoulder without bunching or twisting.

5. Tension & Seal: Pull the fabric upward evenly from both sides to ensure tautness across the 39" × 50" span (loose fabric allows DE cakes to bridge, sag, and slough off under vacuum). Firmly press the top Velcro flap closed across the upper frame rail to lock in tension.

6. Mount Felt Collar: Slide a new felt compression collar onto the corner outlet spud against the locating shoulder before lowering the re-covered leaf back into the Keene-Bowser floor manifold receiver.