Section 8 — Heat Transfer Equipment

Spiral Heat Exchangers

IPE Engineering Practice IPE-EP-8-1-6

Document number: IPE-EP-8-1-6 · Section: 8 — Heat Transfer Equipment

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SCOPE

This Practice governs the general requirements for the materials, design, fabrication, inspection, testing and preparation for shipment of spiral heat exchangers for use in process services.

This Practice governs the general requirements for the materials, design, fabrication, inspection, testing and preparation for shipment of spiral heat exchangers for use in chemicals’ process services.

This Practice, in general, governs the requirements that are unique to the design of spiral heat exchangers and must be used in conjunction with EP 7–1–1 which covers requirements for pressure vessels constructed per the ASME Code, Section VIII, Division 1.

Any deviation from this Practice or Practices referenced herein must be approved by the procedure described in EP 1–1–3.

Supplemental requirements for spiral heat exchangers are covered in EP 7–1–4.

An asterisk (*) indicates that a decision by the Owner or Owner’s Engineer is required, or that additional information is furnished by the Purchaser.

A revision bar indicates all changes made to this Revision.

REFERENCES

The latest edition of the following standards and publications are referred to herein.

STANDARDS AND PUBLICATIONS

DEFINITIONS

• Contractor – Company or business that agrees to furnish materials or perform specified services at a specified price and/or rate to the Owner.
• Manufacturer – The recipient of a direct or indirect purchase order for materials and/or equipment. In this context, a direct order is one issued to a Manufacturer by a Contractor or the Owner. An indirect order is one issued to a Manufacturer by a vendor (recipient of a direct order) for materials, fabricated components, or subassemblies.
• Owner – Inflection Point Engineering, LLC.
• Owner’s Engineer – A CInflection Point Engineering, LLC appointed engineer.
• Purchaser – The party placing a direct purchase order. The Purchaser is the Owner’s designated representative.

DATA SHEET, DOCUMENTATION AND PURCHASING REQUIREMENTS

• Data Sheet of EP 8–1–6 DS and documentation requirements for spiral heat exchangers shall be in accordance with EP 7–1–4 and the additional requirements of this Practice.
• The following spare parts shall be provided by the Manufacturer:
• Two (2) spare sets of end cover gaskets.
• Six (6) hook bolt assemblies.

DESIGN AND CONSTRUCTION

• General

As a minimum requirement, spiral heat exchangers shall be designed, fabricated, and stamped in accordance with State Rules and Regulations and the ASME Boiler and Pressure Vessel Code, Section VIII, Division I, latest edition. All units shall be stamped with a National Board Number, and where applicable, State Special Number.

• Process
• The exchanger shall be of single passage and preferably of counter current flow design. Cross flow is acceptable where a high imbalance of volumetric flow exists or a low pressure drop is required.
• (*) All liquid to liquid services shall be horizontally mounted. Liquid channel velocities shall not exceed 10 ft/s, unless approved by the Owner’s Engineer.
• All condenser, gas or vaporizer services, shall be vertically mounted. Vapor channel velocities shall not exceed 125 ft/s.
• All slurry or abrasive fluid services shall have spacer studs in line. Slurries shall have a minimum channel velocity of 2 ft/s. For severely abrasive services, the spiral element thickness shall be a minimum of 0.25 inches thick throughout.
• (*) The fouling factor shall be suitable for the service. Where conventional shell and tube fouling factors are given by the Owner’s Engineer, the spiral exchanger equivalent shall be used.

• Where a highly fouling cooling water source is used, a pin–hole free baked phenolic coating on the water channel shall be offered as a cost extra. Wall resistance shall be increased by 0.0004 hr–ft2–°F/Btu to account for the coating resistance.

• Mechanical
• The design pressure and temperature shall be as shown on the Data Sheet of EP 8–1–6 DS and shall be per EP 7–1–1.
• (*) The spiral exchanger shall be designed to withstand the full design pressure on each side. Differential pressure designs are not permitted without approval of the Owner’s Engineer.
• All exchangers shall be equipped with removable covers on both ends.
• Covers shall be attached with through bolted or hook bolted flanged joints. All bolts shall be a minimum 3/4 inch diameter with a maximum spacing between bolt center lines of 6 inches.
• The minimum channel spacing shall be1/4 inch or the maximum fluid particle size plus 1/8 inch, whichever is larger.
• The minimum spiral element thickness shall be 0.1875 inches for carbon steel units and 0.105 inches for stainless steel or alloy units. Continuous coil material should be used whenever possible.
• The minimum nozzle thickness shall be in accordance with Table 6 of EP 7–1–1.
• Both end covers shall be matched marked with the shell section to insure proper alignment.
• Materials
• Materials shall conform with this Practice, the Data Sheet, and Table 1 of EP 7–1–1.
• Material used for channel seals shall be of the same material as the spiral elements to which it is welded.
• Both heads shall be carbon steel designed in accordance with ASME Code rules and formulas. Where stainless steel or alloy materials are specified, the heads shall be lined with appropriate alloy material per EP 7–1–6.
• Bolt material shall be in accordance with EP 7–1–1.
• Nozzles and Other Connections
• Nozzles and nozzle flanges shall be in accordance with EP 7–1–1.
• Chemical cleaning connections, instrument connections, vents and drains, and other connections shall be designed in accordance with EP 7–1–1 and the additional requirements of this Practice.
• One NPS 1 inch instrument connection shall be provided in each nozzle, and shall be in accordance with EP 7–1–1.
• (*) Chemical cleaning connections shall be provided at the inlet and outlet of exchangers in cooling water service, or when specified by the Owner’s Engineer. When the nozzles are less than NPS 4 inch, the chemical cleaning connections shall be located in the connecting piping in accordance with EP 5–1–2.
• Chemical cleaning connections shall be NPS 1–1/2 inch connections for nozzles NPS 4 inch or NPS 6 inch, and NPS 2 inch connections shall be provided on NPS 8 inch or larger nozzles.
• Vents and drains shall be provided at high and low points of the exchanger. Vents and drains are in addition to instrument or chemical cleaning connections.
• (*) Unless otherwise specified by the Owner’s Engineer, vents and drains shall be a NPS 1 inch minimum. Vents and drain connections shall be in accordance with EP 7–1–1.

• Gaskets and Gasket Grooves
• Compressed asbestos gaskets are not acceptable.
• (*) Unless otherwise specified, two spare set of gaskets shall be furnished with each exchanger.
• If a tongue and groove design is used for the end covers, the joint tongue shall be on the removable covers.
• Vessel Supports, Structural Attachments, and Lifting Lugs
• Horizontal units shall have at least two support saddles with two holes for anchor bolts.
• Vertical units shall have at least two support pads, each pad to have two holes for anchor bolts.
• Lifting lugs shall be provided on the spiral element and both covers.

FABRICATION

• General

Fabrication shall be in accordance with EP 7–1–1.

• Welding

Welding shall conform to EP 7–1–5.

• Machining

Out–of–flatness tolerance on end cover gasket surfaces shall not exceed ± 0.0035 inch over the entire circumference. For spiral exchangers with a maximum operating temperature above

500 °F, the out of–flatness tolerance on the end cover gasket surfaces shall not exceed ± 0.0025 inch over the entire circumference.

INSPECTION AND TESTING

• General

Inspection and testing shall be in accordance with EP 7–1–1.

• Magnetic Particle and Liquid Penetrant Inspection
• Magnetic particle and liquid penetrant inspection shall be in accordance with EP 7–1–1 and the additional requirements given in this Practice.
• The back side of the spiral plate butt welds shall be magnetic particle or liquid penetrant inspected. Indications found shall be removed to sound metal and repaired.
• Hydrostatic Test
• Hydrostatic testing shall be in accordance with EP 7–1–1 and the additional requirements of this Practice.
• Spiral heat exchangers shall have each passage tested separately.

8.0 PAINTING, MARKING, PACKAGING AND SHIPPING

Painting, marking, packaging, and shipping requirements for spiral heat exchangers shall be in accordance with EP 7–1–1.

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