# Ohm Engineers — full brief
> Companion to https://www.ohmengineers.co.in/llms.txt. Use the short file first. This file adds RFQ fields, product hierarchy, and the remaining knowledge index.

Ohm Engineers is an Indian engineering manufacturer at GIDC Manjusar-Savli, Vadodara. Primary product: TEMA-practice shell-and-tube heat exchangers (including U-tube, double-pipe and kettle reboilers). Secondary lines: multi-stage steam jet vacuum systems, hybrid ejector + liquid-ring packages, double stage vacuum boosters, distillation columns, jacketed reactors, multi-effect evaporators, dosing systems, and food / dairy process equipment. All are made to order from process data or buyer drawings. Markets: Gujarat industrial belts, pan-India, and GCC export (see https://www.ohmengineers.co.in/export/process-equipment-saudi-arabia-gcc).

Works: Plot No. 348, G.I.D.C. Manjusar-Savli, Vadodara, Gujarat 391775, India.
Founded: 2004. Held certification: ISO 9001:2015.
Email: info@ohmengineers.co.in. Phone: +91 83470 19128/22.

Key geo pages: https://www.ohmengineers.co.in/india/gujarat, https://www.ohmengineers.co.in/india, https://www.ohmengineers.co.in/sa, https://www.ohmengineers.co.in/ae, https://www.ohmengineers.co.in/global.

Materials commonly listed: carbon steel; stainless steel SS 304 / 316 / 316L; duplex when specified; other alloys when the enquiry names them and mill supply is feasible.

Inspection and test (as specified on the ITP): dimensional checks, weld visual, NDT (RT / UT / DPT as applicable), hydrostatic test of pressure parts, mill test certificates for pressure-boundary materials.

## How to request a quote
- [Technical RFQ form](https://www.ohmengineers.co.in/rfq): Preferred. Attach a datasheet or GA if the buyer already has one.
- [Heat exchanger RFQ checklist](https://www.ohmengineers.co.in/products/heat-exchangers/rfq-checklist)

Useful RFQ fields (omit what the buyer does not yet know — do not invent values):
- Product / configuration (shell-and-tube, U-tube, double-pipe, kettle reboiler, or other named equipment)
- Application and industry
- Hot-side and cold-side fluids
- Flow rates
- Heat duty
- Inlet and outlet temperatures
- Operating and design pressures
- Allowable pressure drop (shell and tube)
- Fouling factors if named by the plant or licensor
- Design code (TEMA class, ASME VIII-1, IS 2825, other)
- Inspection / TPI / ITP hold points
- Materials of construction
- Quantity, delivery location, and required date if known
- Contact name, company, email, phone, country

## Heat exchangers
- [Industrial heat exchangers](https://www.ohmengineers.co.in/products/heat-exchangers)
- Shell & Tube Heat Exchangers: Engineered heat-transfer equipment for process heating, cooling, condensing and heat recovery — the primary configuration Ohm manufactures.
- U-Tube Heat Exchangers: Removable U-tube bundles for duties with large tube-to-shell temperature difference or where the bundle must come out for shell-side cleaning.
- Rectangular Cross Flow Box Type Heat Exchanger: Rectangular box-type cross-flow exchangers for duties where this layout is specified on the drawing or process case.
- Double-Pipe Heat Exchangers: Pipe-in-pipe (hairpin) exchangers for high-pressure, high-temperature, or modest-area duties where a full shell-and-tube unit is not justified.
- Kettle-Type Reboilers: Enlarged-shell (TEMA K) reboilers for column bottoms and vaporising services that need disengagement space above the bundle.

## Other equipment
- [Gland Type / Limpet Type Reactors](https://www.ohmengineers.co.in/products/reactors): Gland type and limpet type chemical reactors for synthesis, mixing, polymerization, and batch reaction duty. Jacketed and agitated configurations fabricated to drawing.
- [Pressure Vessels](https://www.ohmengineers.co.in/products/pressure-vessels): Unfired process pressure vessels fabricated in Vadodara from purchaser drawings and the named design code — ASME Section VIII Division 1 or IS 2825 when specified.
- [Distillation & Fractionation Columns](https://www.ohmengineers.co.in/products/distillation-columns): Custom-engineered distillation and fractionation columns with trays, packed beds, or structured packing for separation of chemical mixtures in process industries.
- [Dosing Systems](https://www.ohmengineers.co.in/products/dosing-systems): Precise chemical dosing and metering systems for water treatment, chemical processing, and pharmaceutical applications. Skid-mounted and ready to install.
- [Multi Effect Evaporators](https://www.ohmengineers.co.in/products/multi-effect-evaporators): Energy-efficient multi-effect evaporator systems for concentration of liquids, zero-liquid-discharge, and water recovery. 2-effect to 7-effect configurations available.
- [Steam Jet Vacuum Systems](https://www.ohmengineers.co.in/products/steam-jet-vacuum-systems): Multi-stage steam jet ejectors with intercondensers (direct-contact or surface) as specified. Configuration and suction pressure follow the process case — not a single published vacuum rating.
- [Vacuum Packages](https://www.ohmengineers.co.in/products/vacuum-packages): Complete packaged vacuum systems combining steam jet ejectors with liquid ring pumps, condenser units, and skid-mounted controls for plug-and-play installation.
- [Non-Metallic Venturi & Liquid Jet Ejectors](https://www.ohmengineers.co.in/products/non-metallic-venturi-ejectors): Corrosion-resistant polypropylene, PVDF, and FRP venturi ejectors and liquid jet pumps for handling highly corrosive acids, alkalis, and solvents.
- [Food & Dairy Plant Equipment](https://www.ohmengineers.co.in/products/food-dairy-equipment): Hygienic stainless process equipment for food, dairy and pharmaceutical plants when the specification calls for that construction. Sanitary stamps (3-A, FSSAI product approval) are not listed as certifications Ohm holds by default.
- [Double Stage Vacuum Booster](https://www.ohmengineers.co.in/products/double-stage-vacuum-booster): Two-stage steam-jet vacuum booster packages with intercondenser — fabricated in Vadodara from purchaser suction load, motive steam and cooling-water data.
- [Hybrid Steam Ejector & Liquid Ring Vacuum Systems](https://www.ohmengineers.co.in/products/hybrid-steam-ejector-liquid-ring-systems): Combination vacuum packages — multi-stage steam jet ejectors with liquid ring vacuum pump backing — for deep, stable vacuum and utility-optimised refinery and chemical duties.

## Remaining knowledge articles
- [API 660 Heat Exchanger Overview](https://www.ohmengineers.co.in/knowledge-center/api-660-heat-exchanger-overview): API 660 is a purchaser specification for shell-and-tube exchangers. Ohm designs to it when it is attached to the enquiry — it is not an Ohm certification.
- [Heat Exchanger Testing Procedures](https://www.ohmengineers.co.in/knowledge-center/heat-exchanger-testing-procedures): Pressure parts are hydrotested. NDT follows the ITP. Do not assume pneumatic or helium leak testing is standard on every Ohm unit.
- [Causes of Heat Exchanger Failure](https://www.ohmengineers.co.in/knowledge-center/causes-of-heat-exchanger-failure): Most exchanger failures are tube leaks, vibration wear, expansion damage, or gasket/partition leaks. Fix the mechanism; a larger replacement of the same layout will repeat it.
- [How to Reduce Heat Exchanger Fouling](https://www.ohmengineers.co.in/knowledge-center/how-to-reduce-heat-exchanger-fouling): Fouling is slowed by hydraulics, chemistry, and where you put the dirty fluid. Extra area without velocity control just delays the same shutdown.
- [Heat Exchanger Cleaning Methods](https://www.ohmengineers.co.in/knowledge-center/heat-exchanger-cleaning-methods): Cleaning method is a design input. Straight tubes and a removable cover, a pullable U-bundle, or chemical-only access are decided on the GA — not at the first outage.
- [Fixed Tube Sheet vs Floating Head Heat Exchanger](https://www.ohmengineers.co.in/knowledge-center/fixed-tubesheet-vs-floating-head-heat-exchanger): Floating head is a TEMA rear-end family. Ohm builds fixed-tubesheet units, with or without a shell expansion joint, and U-tube as the removable-bundle option.
- [How to Size a Heat Exchanger](https://www.ohmengineers.co.in/knowledge-center/how-to-size-a-heat-exchanger): Size from duty, LMTD, and a realistic U — then check pressure drop and vibration. Send complete stream data. Do not treat a website as a kW rating table.
- [Types of Heat Exchangers](https://www.ohmengineers.co.in/knowledge-center/types-of-heat-exchangers): Name the type from duty and maintainability. Ohm manufactures four tubular configurations. Plate, air-cooled, and floating-head units are industry options — not items on this shop's SKU list.
- [Shell & Tube Heat Exchanger: Design and Applications](https://www.ohmengineers.co.in/knowledge-center/shell-and-tube-heat-exchanger-design-and-applications): Shell-and-tube remains the default industrial configuration when pressure, area, and cleanability must be specified on a drawing.
- [Heat Exchangers for Food & Dairy Applications](https://www.ohmengineers.co.in/knowledge-center/heat-exchanger-for-food-and-dairy): Food and dairy exchangers need the hygienic rules written on the order. 'Food grade' without finish, fittings, and CIP intent is not a specification.
- [Multi-Effect Evaporators: Working Principle, Configurations and Energy Savings](https://www.ohmengineers.co.in/knowledge-center/multi-effect-evaporator-working-principle): A triple-effect evaporator consumes roughly one-third the steam of an equivalent single-effect unit. Understanding how multiple effects work, which feed arrangement suits your liquid, and what determines steam economy helps you specify the right system.
- [Heat Exchangers for Oil & Gas](https://www.ohmengineers.co.in/knowledge-center/heat-exchanger-for-oil-and-gas): Energy-sector exchangers are specification-driven. Attach the purchaser standard. Do not rely on a website to replace SAES, DEP, or API data sheets.
- [Heat Exchangers for Pharmaceutical Applications](https://www.ohmengineers.co.in/knowledge-center/heat-exchanger-for-pharmaceutical-applications): Pharma specifications succeed when finish, material certificates, and cleaning are written down. They fail when 'GMP' is used as a substitute for data.
- [Materials of Construction for Process Equipment: A Practical Selection Guide](https://www.ohmengineers.co.in/knowledge-center/moc-selection-process-equipment): Choosing the wrong material of construction is one of the most expensive mistakes in process equipment. Over-specifying exotic alloys wastes capital; under-specifying causes corrosion failures within months. This guide gives you the decision logic.
- [Heat Exchangers for Chemical Processing](https://www.ohmengineers.co.in/knowledge-center/heat-exchanger-for-chemical-processing): Chemical duties fail from chemistry and specification gaps more often than from fabrication. Name the fluid, contaminants, and cleaning method.
- [Heat Exchanger Troubleshooting](https://www.ohmengineers.co.in/knowledge-center/heat-exchanger-troubleshooting): If duty has fallen, decide whether the process changed, the unit is dirty, the bundle is bypassing, or a leak is mixing streams — before you buy a larger exchanger.
- [Heat Exchanger Maintenance](https://www.ohmengineers.co.in/knowledge-center/heat-exchanger-maintenance): Maintainability is designed in: channel access, bundle pull space, davits, and metallurgy. A unit that cannot be cleaned will not hold duty.
- [Heat Exchanger Material Selection](https://www.ohmengineers.co.in/knowledge-center/heat-exchanger-material-selection): Material is a corrosion and code decision owned by the process engineer. The fabricator executes the specified MOC — they should not guess it from a marketing page.
- [Heat Exchanger Design Considerations](https://www.ohmengineers.co.in/knowledge-center/heat-exchanger-design-considerations): A working design balances thermal duty, hydraulics, mechanical integrity, and how the unit will be cleaned and inspected for the next decade.
- [Falling Film vs Forced Circulation Evaporators: Which Suits Your Liquid?](https://www.ohmengineers.co.in/knowledge-center/falling-film-vs-forced-circulation-evaporator): Falling film evaporators offer short residence time for heat-sensitive products. Forced circulation handles viscous, scaling, and crystallising liquids that would choke a falling film unit. The wrong choice causes fouling, product degradation, or inability to reach target concentration.
- [Heat Exchanger Pressure Drop](https://www.ohmengineers.co.in/knowledge-center/heat-exchanger-pressure-drop): Allowable pressure drop is a process constraint, not a vendor preference. It decides baffle spacing, pass count, nozzle size, and sometimes whether the unit will vibrate.
- [U-Tube vs Shell & Tube Heat Exchanger](https://www.ohmengineers.co.in/knowledge-center/u-tube-vs-shell-and-tube-heat-exchanger): Both are shell-and-tube family. The difference is the rear end: U-bends versus a second tubesheet. That choice governs expansion, cleaning, and leak repair.
- [Steam Jet Ejectors: Working Principle, Multi-Stage Systems and Selection Guide](https://www.ohmengineers.co.in/knowledge-center/steam-jet-ejector-working-principle-selection): Steam jet ejectors have no moving parts, handle corrosive vapours, and achieve deep vacuum. But they consume significant motive steam and need condenser cooling water. Here is a complete technical guide to selection, staging, and sizing.
- [Shell and Tube vs Plate Heat Exchanger: Choosing the Right Type for Your Process](https://www.ohmengineers.co.in/knowledge-center/shell-tube-vs-plate-heat-exchanger): Plate heat exchangers cost less and are more thermally efficient for clean services. Shell-and-tube handles higher pressures, temperatures, fouling services, and phase changes that plates cannot. The right choice depends on your specific process — not general rules.
- [Vacuum System Leak Rate Testing: Acceptance Criteria and Methods](https://www.ohmengineers.co.in/knowledge-center/vacuum-system-leak-rate-testing): A vacuum system that cannot hold vacuum will never achieve design suction pressure. Leak rate testing — by pressure rise or helium sniffing — is the standard acceptance test before handing over to operations.
- [Liquid Ring Vacuum Pump Selection: When to Use Instead of Steam Ejectors](https://www.ohmengineers.co.in/knowledge-center/liquid-ring-vacuum-pump-selection): Liquid ring vacuum pumps are motor-driven, handle condensable vapours well, and suit moderate vacuum levels. They consume electricity and seal water rather than motive steam — the right choice depends on your utilities and suction pressure target.
- [ASME Section VIII Pressure Vessels: A Practical Guide for Buyers and Engineers](https://www.ohmengineers.co.in/knowledge-center/asme-section-viii-pressure-vessel-guide): ASME Section VIII is the code that keeps pressure vessels from killing people. Division 1 or Division 2, U-stamp or UM-stamp, Form U-1 or U-1A — here is what each means and what you should demand from a certified fabricator.
- [Hydrostatic Testing of Pressure Vessels: What Buyers Should Witness](https://www.ohmengineers.co.in/knowledge-center/hydrostatic-test-pressure-vessels): The hydrostatic test is the final proof that a pressure vessel can safely contain its design pressure. Knowing what to expect — test pressure, hold time, examination criteria — helps you verify compliance before accepting delivery.
- [Pressure Relief Valve Sizing for Pressure Vessels and Reactors](https://www.ohmengineers.co.in/knowledge-center/pressure-relief-valve-sizing-vessels): Every ASME pressure vessel requires overpressure protection. Understanding the relief scenarios — fire, blocked outlet, runaway reaction, thermal expansion — helps you verify that the fabricator's PRV sizing is correct before installation.
- [Chemical Reactor Types: Batch, CSTR, and Jacketed Vessel Selection](https://www.ohmengineers.co.in/knowledge-center/chemical-reactor-types-selection-guide): Reactor selection depends on reaction kinetics, heat removal rate, mixing intensity, and phase behaviour. Specifying the wrong jacket type or agitator geometry is one of the most common causes of scale-up failure.
- [Distillation Column Design: Key Parameters Process Engineers Must Specify](https://www.ohmengineers.co.in/knowledge-center/distillation-column-design-fundamentals): A distillation column enquiry that only states 'separate component A from B' will receive a quotation based on assumptions. Here are the parameters that determine column diameter, height, tray count, and material selection.
- [Weld Joint Efficiency in ASME Vessels: RT, Spot RT, and No RT Explained](https://www.ohmengineers.co.in/knowledge-center/weld-joint-efficiency-rt-ut-explained): Joint efficiency (E) is the factor that converts calculated minimum wall thickness to actual required thickness. Full RT (E=1.0) allows thinnest walls but costs more in inspection. Understanding E values helps you specify the right NDE level in your purchase order.
- [Tube Vibration and Baffle Spacing in Shell-and-Tube Heat Exchangers](https://www.ohmengineers.co.in/knowledge-center/shell-tube-tube-vibration-baffle-spacing): Tube vibration is a leading cause of bundle failure in refinery and chemical exchangers. Baffle spacing, shell-side velocity, and tube span limits must be checked at design stage — not after tubes start leaking.
- [ISO 9001:2015 for Equipment Buyers: What Certification Actually Means](https://www.ohmengineers.co.in/knowledge-center/iso-9001-equipment-buyers-guide): ISO 9001 tells you the manufacturer has a documented quality management system — it does not guarantee your specific vessel is correctly designed. Here is what to verify beyond the certificate.

## Optional
- [Short LLM overview](https://www.ohmengineers.co.in/llms.txt): Start here. Curated conversion paths only.
- [XML sitemap](https://www.ohmengineers.co.in/sitemap.xml): Complete indexable URL list for search engines — not a substitute for llms.txt.