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Gasketed Plate Heat Exchangers
Skid mounted plate heat exchangers for Dairy, Food, and Beverage Processing Industries A plate heat exchanger is a type of heat exchanger that uses metal plates to transfer heat between two fluids. This has a major advantage over a conventional heat exchanger in that the fluids are exposed to a much larger surface area because the fluids spread out over the plates. This facilitates the transfer of heat, and greatly increases the speed of the temperature change. Plate heat exchangers are now common and very small brazed versions are used in the the hot-water sections of millions of combination boilers. The high heat transfer efficiency for such a small physical size has increased the domestic hot water (DHW) flow rate of combination boilers. The small plate heat exchanger has made a great impact in domestic heating and hot-water. Larger commercial versions use gaskets between the plates, smaller version tend to be brazed.
The concept behind a heat exchanger is the use of pipes or other containment vessels to heat or cool one fluid by transferring heat between it and another fluid. In most cases, the exchanger consists of a coiled pipe containing one fluid that passes through a chamber containing another fluid. The walls of the pipe are usually made of metal, or another substance with a high thermal conductivity, to facilitate the interchange, whereas the outer casing of the larger chamber is made of a plastic or coated with thermal insulation, to discourage heat from escaping from the exchanger.
The plate heat exchanger (PHE) was invented by Dr Richard Seligman in 1923 and revolutionised methods of indirect heating and cooling of fluids. Dr Richard Seligman founded APV in 1910 as the Aluminium Plant & Vessel Company Limited, a specialist fabricating firm supplying welded vessels to the brewery and vegetable oil trades.
Design of plate and frame heat exchangers
The plate heat exchanger (PHE) is a specialized design well suited to transferring heat between medium- and low-pressure liquids. Welded, semi-welded and brazed heat exchangers are used for heat exchange between high-pressure fluids or where a more compact product is required. In place of a pipe passing through a chamber, there are instead two alternating chambers, usually thin in depth, separated at their largest surface by a corrugated metal plate. The plates used in a plate and frame heat exchanger are obtained by one piece pressing of metal plates. Stainless steel is a commonly used metal for the plates because of its ability to withstand high temperatures, its strength, and its corrosion resistance. The plates are often spaced by rubber sealing gaskets which are cemented into a section around the edge of the plates. The plates are pressed to form troughs at right angles to the direction of flow of the liquid which runs through the channels in the heat exchanger. These troughs are arranged so that they interlink with the other plates which forms the channel with gaps of 1.3-1.5 mm between the plates.
The plates produce an extremely large surface area, which allows for the fastest possible transfer. Making each chamber thin ensures that the majority of the volume of the liquid contacts the plate, again aiding exchange. The troughs also create and maintain a turbulent flow in the liquid to maximize heat transfer in the exchanger. A high degree of turbulence can be obtained at low flow rates and high heat transfer coefficient can then be achieved.
A plate heat exchanger consists of a series of thin, corrugated plates which are mentioned above. These plates are gasketed, welded or brazed together depending on the application of the heat exchanger. The plates are compressed together in a rigid frame to form an arrangement of parallel flow channels with alternating hot and cold fluids. As compared to shell and tube heat exchangers, the temperature approach in a plate heat exchangers may be as low as 1oC whereas shell and tube heat exchangers require an approach of gives 5oC or more. For the same amount of heat exchanged, the size of the plate heat exchanger is smaller, because of the large heat transfer area afforded by the plates (the large area through which heat can travel). Expansion and reduction of the heat transfer area is possible in a plate heat exchanger.
Evaluating plate heat exchangers All plate heat exchangers look similar on the outside. The difference lies on the inside, in the details of the plate design and the sealing technologies used. Hence, when evaluating a plate heat exchanger, it is very important not only to explore the details of the product being supplied, but also to analyze the level of research and development carried out by the manufacturer and the post-commissioning service and spare parts availability.
An important aspect to take into account when evaluating a heat exchanger are the forms of corrugation within the heat exchanger. There are two types: intermating and chevron corrugations. In general, greater heat transfer enhancement is produced from chevrons for a given increase in pressure drop and are more commonly used that intermating corrugations
Advantages and disadvantages of plate heat exchangers
Advantages
- Compactness- The units in a plate heat exchanger occupy less floor space and floor loading by having a large surface area that is formed from a small volume. This in turn produces a high overall heat transfer coefficient due to the heat transfer associated with the narrow passages and corrugated surfaces.
- Flexibility- Changes can be made to heat exchanger performance by utilizing a wide range of fluids and conditions that can be modified to adapt to the various design specifications. These specifications can be matched with different plate corrugations.
- Low Fabrication Costs- Welded plates are relatively more expensive than pressed plates. Plate heat exchangers are made from pressed plates, which allow greater resistance to corrosion and chemical reactions.
- Ease of Cleaning- The heat exchanger can be easily dismantled for inspection and cleaning (especially in food processing) and the plates are also easily replaceable as they can be removed and replaced individually.
- Temperature Control- The plate heat exchanger can operate with relatively small temperature differences. This is an advantage when high temperatures must be avoided. Local overheating and possibility of stagnant zones can also be reduced by the form of the flow passage.
Disadvantages
- The main weakness of the plate and frame heat exchanger is the necessity for the long gaskets which holds the plates together. Although these gaskets are seen as a weakness towards this type of heat exchanger, it has been successfully run at high temperatures and pressures.
- There is a potential for leakage even though the leaks that occur are sent to the atmosphere and not between process streams.
- The pressure drop that occurs through a plate heat exchanger is relatively high and the running costs and capital of the pumping system should be considered.
Plate Heat Transfer Equation The total rate of heat transfer between the hot and cold fluids passing through a plate heat exchanger may be expressed as: Q = UAÃŽâ€Tm where U is the overall heat transfer coefficient, A is the total plate area, and âˆâ€ Tm is the temperature difference. U is dependent upon the heat transfer coefficients in the hot and cold streams.
Efficiency and Flexibility
Easy to Remove and Clean
You simply remove the tie bolts and slide back the movable frame part. Now the plate pack can be inspected, pressure cleaned, or removed for refurbishment if required.
Expandable
A very significant feature of the plate heat exchanger is that it is expandable. Increasing your heat transfer requirements means simply adding plates instead of buying a new heat exchanger, saving time and money.
High Efficiency
Because of the pressed patterns in the plates and the relative narrow gaps, very high turbulence is achieved at relative low fluid velocity. This combined with counter directional flow results in very high heat transfer coefficients.
Compact Size
As a result of the high efficiency, less heat transfer area is required, resulting in a much smaller heat exchanger than would be needed for the same duty using other types of heat exchangers. Typically a plate heat exchanger requires between 20-40% of the space required by a tube & shell heat exchanger.
Close Approach Temperature
The same features that give the plate heat exchanger its high efficiency also makes it possible to reach close approach temperatures which is particularly important in heat recovery and regeneration applications. Approach temperatures of 1oF are possible.
Multiple Duties in a Single Unit
The plate heat exchanger can be built in sections, separated with simple divider plates or more complicated divider frames with additional connections. This makes it possible to heat, regenerate, and cool a fluid in one heat exchanger or heat or cool multiple fluids with the same cooling or heating source.
Avoid cross contamination
each medium is individually gasketed and as the space between the gaskets is vented to the atmosphere, cross contamination of fluids is eliminated.
Less Fouling
Very high turbulence is achieved as a result of the pattern of the plates, the many contact points, and the narrow gap between the plates. This combined with the smooth plate surface reduces fouling considerably compared to other types of heat exchangers.
Lower Costs
High heat transfer coefficients mean less heat transfer area and smaller heat exchangers, and sometimes even less heat exchangers. This and less space requirements, reduced flow rates, and smaller pumps means JMD Sonic - PHE Applications Food Processing
Dairy
- Milk pasteurization,
- Milk reception,
- Raw Milk Cooling,
- Cultured milk treatment,
- UHT,
- Cream pasteurization,
- Ice-cream mix treatment,
- Cheese milk heat treatment.
Brewing
- Wort boiling,
- Wort cooling
- Beer cooling,
- Beer pasteurization
- Beerwort Cooling
Soft Drink
- Pasteurization of syrup and final product
- Water heating and sugar dissolving of final product.
Fruit Processing
- Pasteurization of juices, nectar, and concentrates,
- Cooling of final product.
Misc
- Edible Oil Heating/Cooling,
- Hot Water Generators
- Tomato Sauce Processing
Chemical Processing
Petroleum
- Refinery - Brine cooling, crude oil/water interchanger, treated crude oil /untreated crude oil interchanger.
- MTBE - Product heating, cooling & interchanging, jacket water cooling, condensing.
- Alkylotion - Cooling, hearing of corrosive fluids, Isobutene condenser and reactor interchanger.
- Oil & Gas - Sea water coolers, crude oil heat treatment.
- Dehydration/Desolving - Crude oil interchanger, water/crude oil interchanger, water interchanger, crude oil cooling.
- Desulphurization - Lean/rich fluid interchanger & cooling, acid gas condensor.
Hydrocarbon Processing
- Methanol - Preheating, water cooling, liquid product cooling.
- Propylene Oxide - Sodium hydroxide cooling, reaction mixture cooling, heat recovery from reactor bottom liquid.
- Ethylene Glycol - Product cooling, reactor feed heater and interchanger.
- Ethylene Oxide - Lean/rich cycle water interchanger, lean cycle water cooler.
- Ethylene-Propylene - water cooling & heating, propylene condensers, propylene cooling, naphtha preheating.
- Formaldehyde - Methanol preheating, formalin cooling, water cooling.
Polymer
- Acrylic Fibers - Heating & cooling of solvents, reactor cooling.
- Nylon - Water cooling & heating, nylon salt cooling, condensers and interchangers.
- Polyester - Glycol cooling, solvent heating.
- Polyethylene - Pelleter water & cooling water systems.
- Polyol - Water heating & cooling, reactor feed heating & cooling, polyol product cooling, polyol mix heating.
- Polypropylene - Circulating, pellet, refrigerated and feed matercooling, condensers and interchangers.
- Polyurethane - Heating & cooling of polyol and isocyanate.
- PVC - Reactor jacket water cooling.
- Viscose - Heating & Cooling of NaOH, viscose and different acides, heating of spin bath solution
- Brine Heating and Cooling
- Sulfuric Acid Processing
- Caustic Soda Processing
- Vapor Condensation
- Salt Refining
- Resin Cooling
Pharmaceutical
Product heating & cooling, cooling water systems, hot water systems, condensers & interchangers.
Industrial
Mining- Plating heaters & coolers, analyzing heaters & coolers, strike solution cooling, quench oil coolers, sulfuric acid, hydrochloric acid, hydrogen peroxide, titanium dioxide, chloride alkaline, soda ash, steel.
Automotive
- Pickling - Sulfuric and hydrochloric acid heating and cooling.
- Rinsing - Heating rinsing water.
- Phosphatizing - Phosphoric acid solution heating.
- Passivating - Heat and maintain passicating bath temperature. Precutting Cooling of electrolytic bath solution (5-15% pain and water).
- Priming & Painting - Heat and maintain paint temperature.
- Phosphate Solution Cooling, Paint Heating and Induction Heater Cooling
Pulp and Paper - Blow down liquor coolers, caustic soda coolers, black liquor heating, and boiler blow down heat recovery.
Textile Applications - Heat recovery, caustic solution heating & cooling washers.
Vegetable Oil - Product heating, product cooling, product economizing, cooling water systems, hot water systems, waste water treatment.
Sugar - Water, juice, syrup and molasses heating. Juice demineralization and evaporation
General Industrial - Plating Solution Cooling, Anodizing and Cutting Oil Cooling
HVAC (Heating, ventilating and air conditioning)
- Cooling Tower Isolation
- Free Cooling/Chiller Bypass
- Geothermal Heating
- Pressure Interceptor
- Thermal Storage
- District Heating and Cooling
- Water-Source Heat Pumps
- Swimming Pool Heating
- Greenhouse Heating
- Boiler Blow down Heat Recovery
Power
- Auxiliary cooling circuit isolation
- Co-generation applications
- Geothermal applications
- Lubrication oil cooling
- Diesel engine cooling
- Heat recovery.
Marine
- Seawater isolation exchanger
- Central cooling
- Jacket fresh water cooling
- Lube oil cooling
- Camshaft lube
- Oil cooling
- Fresh-Water Generator
- Engine Jacket Cooling
- Lube Oil Cooling
Specialty Products & Applications The versatility of Plate Heat Exchanger-including Free-Flow Plate Heat Exchangers, Sanitary Plate Heat Exchangers, and Fresh Water Distilling Systems-makes them extremely well suited to speciality applications. In all such speciality applications, Plate Exchangers deliver their accustomed benefits of economy, reliability, and serviceability.
Free-Flow Plate Heat Exchangers
The Free-Flow Plate Heat Exchanger accommodates viscous fluids or those containing fibrous materials. The wide-channeled, horizontal-ribbed pattern means that the Free-flow Plate Heat exchanger has no metal-to-metal contact, allowing the free passage of particles that can block the flow in other heat exchangers.
Sanitary Heat Exchangers
For food, dairy, and pharmaceutical processing, sanitary heat exchangers from combine low maintenance, high efficiency, and reliable separation of fluids. Plate gaps in sanitary heat exchangers are sized to reduce fouling; the main pattern creates the needed turbulence for effective heat transmission.
Fresh Water Distillers
Utilizing the heat from diesel engine jacket cooling water, the Fresh Water Distiller evaporates seawater to produce pure drinking water. Contact us for details on the engineering and applications of Fresh Water Distillers.
JMD Sonic - PHE Construction
Plate Heat Exchangers employ outstanding quality in design and construction, delivering effective heat transfer, long life, economical daily operation, and limited repair/maintenance.
Heat Exchanger Construction
Quality demands careful attention to materials and craftsmanship in every heat exchanger we make. Here are the details that add up to superb efficiency, low maintenance and long life from your PHE unit.
PHE's are engineered for low cost in daily operation and low maintenance/repair over the full life of the exchanger.
The Flex system provides the most economical, efficient plate heat exchanger design for any heat transfer application. Several plate sizes are available for each connection size, and plates are pressed in patterns best suited to specific applications
This variety of plate configurations makes all the difference. Combining the right plate geometry, patterns, and connections, the Flex system enables us to customize ideal plate heat exchanger designs for HVAC, chemical processing, food processing, automotive manufacturing, and many other uses.
Flex often eliminates the need for multi-pass designs. All connections can be located in front - so you'll open or close your plate heat exchanger for maintenance, repair, or expansion without disturbing the piping.
Plate-Lock System
Precise alignment and dependable sealing for plate heat exchangers
A patented locking lip at the hanger and guide sections of each plate fastens plates securely together during the critical tightening operation. The Plate-Lock System keeps plates and gaskets tightly aligned, and ensures a tight seal for plate-and-frame heat exchangers even at high working temperatures
Clip-Tite Gasket
An advanced glue-free system for gasketing plate-and-frame heat exchangers
Clip-Tite gasketing offers a combination of positive fluid separation, economy, and easy of use that's perfect for most applications. Integrated gasket clips fasten securely to the plate stampings. And because Clip-Tite gaskets can be fastened without tools, they're simple to replace.
Key advantages of PHE's
- Compact design plate heat exchangers use 80 percent less floor space and weigh a tenth as much as shell-and-tube unit's so they're easier, safer, faster, and more economical to ship, handle, and install.
- Close temperature approach-Countercurrent flow takes exchange media in opposite directions across the plate for big temperature differences and small transfer surface requirements.
- No cross-contamination-Media circuits are individually gasketed; the area between is vented to the atmosphere. Result: no interleakage with plate heat exchangers.
- Low hold-up volume-Inherent design advantages provide shorter response times and more accurate process control.
- Minimum fouling-Uniform flow and high fluid turbulence with the plate design promote constant scrubbing action to reduce fouling.
- Easy maintenance- plate heat exchangers provide low fouling and good drainage. Connections are made to the front; piping stays in place when units are opened.
- Versatility-multiple heating/cooling media can be run with divider sections installed in the heat exchanger.
- Expandability-to enlarge a heat exchanger, just loosen compression bolts and add the plates you need.
- Water savings- plate heat exchangers economize on cooling water and work well even with poor water quality.
- More fluid-related savings- PHEs cut valve, piping and pumping costs.
- Greater efficiency-Plate heat exchangers from use less surface area to accomplish the same heat transfer as shell-and-tube exchangers.
Refurbished plate heat exchangers
Whether you need an industrial, sanitary or a marine heat exchanger, please contact our application engineers with your specifications to get a quotation!
- Custom-designed heat exchangers using refurbished plates and brand new frames and gaskets
- Large inventory of used plates and frame parts- ranging in port sizes from 1/2" to 14"
- We can size a used heat exchanger to your thermal requirements
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