1 RF Generators and RF Matches Used in Induction heating for sealing Medical Clean Room and Food/Freezer Bags
2 Sebra Portable Tube Sealing Induction units Repaired and Serviced
3 Aseptic RF In System Tube Sealing Units Repaired and Serviced
3 RF Generators and Matches for Sterilization Repaired and Serviced
In the Medical Equipment Industry
RF bar sealing systems are widely employed for welding various disposable medical products, ranging from IV bags to aircasts. RF is also used for sealing tarpaulins, truck covers, tents, signs and inflatables.
Nemeth Engineering Associates, Inc. has created several complex medical industry systems. These include presses used for mattresses, IV products, bags, examination tables, oncology, respiratory products, urology and blood collection products. Other medical product systems we’ve built are used for medical pads, cushions, covers, and inflatables.
In the Government Labs
In 1990, an agent acting on behalf of the United States Army Corps of Engineers chose Nemeth Engineering Associates, Inc. to engineer and manufacture suit sealing systems used in its Chemical and Biological decontamination program. Due to the highly critical nature of application, equipment had to be built to minute and exacting specifications. Nemeth delivered and the program continues today.
RF Systems - Mainstay for Automotive & Other Industries
Radio Frequency (RF) or Dielectric heating is a process that has been the efficient and cost-effective backbone of many industries where heat is needed for sealing, welding, drying, curing, or baking of various manufactured products.
PLASTICS - Heat Sealing/Welding, Forming, Preheating
WOOD - Drying, Moisture Leveling, Gluing, Curved Plywood
COMPOSITE MATERIAL - Heating, Curing, Bonding
PRINTING/BINDING - Drying Ink, Curing Glue
FOUNDRIES - Baking Cores, Lost Foam Drying
PAPER - Drying Coatings, Moisture Leveling
TEXTILES - Drying, Bonding Interfacing
RUBBER - Preheating, Vulcanizing
CERAMICS - Drying, Sintering
RF preheaters are used to heat resin and composite materials with a suspended electrode prior to molding. Some automotive components formerly made of steel are now made of composites. Once the composite material is preheated, formed in a mold and cooled, it will never warp or disfigure, regardless of the heat applied to it. Preheaters range in size from 4 kW up to 20 kW and employ either a removable tray or a conveyor belt for the material.
Stray-field RF applicators were developed for heating thin materials such as strands, fabrics or webs. Material is carried on a thin conveyor belt into a system employing parallel rods or structural members between which the high voltage RF field is developed. The material can be passed over, under, or between the electrodes.
Stray-field drying is excellent for paper and webs. If a coating is involved, RF is usually employed in the initial stage. It sets up the coating so that subsequent cylinder dryers and hot air can be used without damaging the surface. Adding RF to the drying chain increases line speed because the resultant rapid drying enables more efficient performance from the following cylinders.
Applications for Radio Frequency and Microwave Heating in the Food industry
The unique processing benefits achievable with RF technology have been used in food applications for many years. Petrie Technologies have worked with the worlds leading food companies to develop novel food processes and products. Examples of such equipment include:
Defrosting
The process advantages include:-
greater yield as a result of reduced drip loss
shorter process time (one hour compared with 48 hours or more)
higher quality
lower bacteriological contamination
Softening
There are number of food ingredients and products which can benefit from softening either as a part of the main process or for recovery of trim or other in-process waste. The ingredients include a range of fats such as shortening for pastry making, cocoa butter and its substitutes.
Baking and post baking
Using RF "post baking’’ product throughput can be increased by up to 30%.
Petrie have developed RF assisted baking processes which can operate within ovens operating up to 300oC. The advantages of this combination baking, include:-
reduced baking time,
more compact machines,
a wider choice of product characteristics arising the separate control of the surface and core heating rates,
choice of full baking or part baking for finishing at point of use
novel product shapes and textures
Cooking and blanching
Radio frequency and microwave heating techniques are useful for a range of continuous cooking operations. Their volumetric heating results in improved product quality. The range of materials which can be cooked include meats and reformed meats, pies and pizzas, vegetables and potato products.
Pasteurization
RF and microwave techniques offers significant opportunities in extending the period between production runs of particular dishes without compromising the shelf life as seen by the customer.
In conjunction with their parent company, NIS Ltd, Petrie also supply conventional steam heated pasteurizers.
Both microwave (MW) and radio frequency (RF) heating (also referred to as dielectric heating) refer to the application of electromagnetic waves to generate heat at regulated frequencies. The frequencies regulated by the U.S. Federal Communications Commission (FCC) for industrial, medical, and scientific purposes are 13.56, 27.12, and 40.68 MHz for RF, and, 915, 2450, 5800, and 24125 MHz for MW applications. Aside from the frequency range and penetration depth, RF and MW heating differ in the nature of the generators and applicators used. Although RF heating is more appropriate for materials of regular shape, large dimensions, and high loss factor, MW heating is better adapted for compact materials with complex shapes and low loss factor.1 Particularly, RF heating provides uniform heating because of its ability to penetrate into the product with uniform field patterns, rather than the complex nonuniform wave patterns found in the MW oven. Continued public concerns about food hygiene issues and demand for conveniently packaged foods with enhanced nutritional quality can require rapid heating alternatives with high penetration into the product. This paper reviews published information on: 1) fundamental principles of RF heating in general; 2) relevant applications and key successes in the food industry; and 3) potential food-related applications that need further investigation.