Knappe Assembly & Operating Instructions 8 inch

Summary

Product identification

This document provides assembly and operating instructions for 8-inch membrane housings. These are Composite Vessels designed for Reverse Osmosis (RO), Nanofiltration (NF), and Ultrafiltration (UF) applications.

• Designed in accordance with the standards of the American Society of Mechanical Engineers (ASME), Boiler and Pressure Vessel Code, Section X.
• Intended for continuous long-term use as a housing for spiral-wound RO, UF, or Nano filtration elements to desalt and purify typical brackish or seawater.
• Any make of 8-inch membranes can be fitted using interfacing adapters.

Materials in contact with the medium:

• Liner: PVC
• Endplates: PP
• Seals: EPDM
• Adapters: PVC
• HP-Ports: 316L (BW), 254SMO/Superduplex (SW)
  • These materials match the requirements of the EU for potable water.

Operating limits

• Permeate stream pressure limit: Should not exceed 150 PSI / 10 bars (unless certified differently).
• Over-pressure protection: Essential that pressure to which any vessel is subjected cannot exceed 105% of design pressure.
• Total weight of branch connection:
  • Feed/concentrate port: Not to exceed 6 kg
  • Permeate port: Not to exceed 4 kg
• Total external stress on end plugs: Not to exceed 100 N.
• Permeate Port connection: Do not tighten more than one turn past hand tight.
• Continuous operating temperature: Inform the factory if less than 45°F.
• Vessel expansion (for a six-element vessel): Approximately 0.7mm in diameter and 6 to 8mm in length under pressure.
• Axial misalignment (Victaulic style clamp): Should not be larger than 0.03 inch / 0.76mm in any direction.
• Thermal expansion for a 6500mm long vessel (at 20K temperature change, thermal elongation coefficient α = 18×10⁻⁶ K⁻¹): 2.34mm.
• Calculated force due to thermal elongation (for a 1000PSI vessel, outer diameter 234mm, inner diameter 208mm, Young's modulus 32000 N/mm²): Approximately 103977 N or 104 KN. Total load exceeds 122 KN when combined with pressure.

Feed water

• Fill the vessels 95% or more with uncompressible media under no pressure. Never fill it with compressible gases.
• Some feed waters may cause corrosion under static conditions; flushing with non-corrosive permeate is recommended.
• After opening the housings, flush the wetted surfaces with fresh water and prevent deposits.
• Before installing elements, ensure that any kind of sand, improper ties, etc., has been removed.
• Loosen deposits carefully with a brush or a sponge in time. Flush away loosened deposits with fresh water.
• The head assembly must be kept free of corrosion.
• If the medium has different properties than water, ensure it does not affect materials in contact. Check medium compatibility also regarding pH level.

Mechanical / hydraulic

General Operation and Safety:

• The vessel is designed for safe operation over a long service life if properly installed, operated, and maintained. Failure to follow guidelines may result in malfunction or catastrophic failure.
• No warranty will be applicable if vessels and assembly parts have been subject to accident, faulty installation, or misapplication of the guide.
• Do not pressurize vessel until end caps have been secured.
• Do not work on any component before verifying pressure is released from the vessel.
• The pressure vessel should not be used as a support for piping manifolds or other fittings.
• Operating personnel should be discouraged from applying undue force to any fittings connected directly to a pressure vessel.
• Provide overpressure protection.
• Never support other components with the vessel; hanging manifolds on ports or using the vessel as fixation for any item may result in vessel damage.
• Double-check end closure installation; ensure that the retaining ring is in place and fully seated.
• Never operate the vessel in excess of its ratings.
• Inspect and maintain the vessel regularly and replace deteriorated parts.

Installation Guidelines:

• Mounting:
  • Support the vessel with horizontal members and saddles. The span should be chosen as indicated in vessel drawings.
  • Maximize the connection flexibility.
  • Position the vessel and the piping so that the vessel can grow in length and diameter under pressure without any undue restraint. An expansion loop in the branch is recommended.
  • Do not mount vessel directly on a rigid support.
  • Do not hard plumb either end of the vessel.
  • Mounting design must allow the vessel to grow freely both axially and radially. Undue restriction can result in damage.
  • Header and related piping should be self-supported; do not use the vessel's ports to support them.
  • Use furnished stainless steel straps; tighten sufficiently to hold the vessel on the support saddles, but not so tightly as to restrict expansion or deform the vessel body.
• Elements:
  • Pressure vessels should be positioned within the system such that elements can be inserted at the upstream end and removed from the downstream end (i.e., elements are installed and removed in the direction of feed flow).
• Lubrication:
  • For installation of all rubber parts (Lip- or O-rings), lubrication by glycerin is required.
  • Do not use lubricating agents which may contain petrol or are made on a petrol basis. Do not use vegetable oil.
  • Sponge or lint-free cloth should be used for application of lubricant.
• Storage: Do not install or store the vessel in direct sunlight; this risks uncontrolled local thermal expansion.
• Head Assembly:
  • Inspect all head components for scratches, foreign matter, corrosion, or damage. Replace damaged components and seals.
  • Install lip rings with the opening (V) towards the inner side of the vessel.
  • Coat all O-rings with a thin layer of Glycerine before installation. Ensure no chips, impurities, or scratches in grooves. O-rings must be completely seated.
  • The HP Port has two positions for the retaining ring: Pos 1 (assembly position) and Pos 2 (working position). This compensates for vessel elongation in the axial direction.

Disclaimer

This summary is based on the provided text extract. It may not include all figures, footnotes, or the latest revisions present in the complete OEM PDF datasheet. For contractual purposes, always refer to the specific OEM PDF revision used on the project.

Official datasheet (PDF)

PDF datasheet