Heat Sealing measurement by an innovative technique

To obtain a proper heat seal is an important requirement in packaging, since seal failure is a more frequent cause of product deterioration than the package itself. Different kinds of seal, such as peelable or non‐peelable, can be obtained by changing the conditions under which a material is sealed. Therefore, identifying these conditions is very important. A new technique, the m ethod for m easuring t emperature of m elting s urface (MTMS), was used to predict the strongest peelable seal on various packaging commercial films. The temperature of the seal interface was measured using a thermocouple. The time–temperature profile, which was obtained by means of a thermocouple, was electronically processed so as to obtain the derivatives of the profile. The inflection point, also called the fusion point, was located on these profiles. This inflection point is associated with the physical change of the state of the material being sealed. The inflection point analysis was done using two different methods: (a) the MTMS method, based on the second derivative of temperature data with time; (b) ‘Table Curve’ software, based on non‐linear regression. This technique was successfully used to evaluate widely used packaging films such as LDPE, HDPE, LLDPE and CPP. The inflection point for these films was identified and the seal strength was verified using a universal testing machine. This method appears to be applicable to design the strongest peelable heat seals for many packaging materials. It also seems to have promise as a method of process measurement and validation for heat seal processes. Copyright © 2006 John Wiley & Sons, Ltd.     

Numerical and experimental evaluation of performance of centrifugal seals

‘Centrifugal seals’ or ‘Slinger seals’ offer an attractive choice as non-contact-type sealing in fluid machinery. These seals utilize the radial pressure gradient caused by centrifugal forces in a rotating fluid ring, to create a sealing of the working fluid. Basic construction of a typical seal consists of a rotating disc inside a stationary casing; one side of the disc (sealing side) is provided with a set of slots (Type-1) or vanes (Type-2) to enhance the tangential velocity of the fluid. The other side of the disk (back side) in both the configurations is exposed to high pressure liquid being sealed. Both numerical and experimental investigations of the performance of Type-1 seal (with slots) have been carried out so as to optimize the seal configuration to achieve maximum sealing capacity, with minimum power consumption. A comparison of the performance of Type-1 seal has been made with that of conventional one (Type-2) in view of economy of construction and better sealing with minimal expense of power consumption. A test rig that allows for varying the major geometrical and operating parameters was designed and tests were conducted with water as the medium. Influence of major geometric parameters like dimensions and number of slots, axial/radial clearances and major operating parameters like rotational speed, inlet pressure and sealing fluid bypass flow rate has been investigated. Apart from various pressure, temperature, flow and torque measurements, the interface between the sealing and working fluid for the experiments was captured and recorded using a high speed camera at ~26,000 frames per second. Geometrical configuration for the slots that maximizes the sealing capacity is arrived through 3D numerical simulations using commercial CFD solver ANSYS Fluent^®. A good agreement is obtained with respect to experimental results. In view of economy of construction and better sealing with minimal expense of operating power, a modified version of Type-1 seal termed as Type-3 seal is investigated. A simple 1D model for prediction of the interface radius during the seal operation, which could be used as a quick design guide, is also presented.     

Requirements for packaging from an ageing consumer's perspective

The overall objective of this research was to explore ageing consumers' attitudes towards currently available food packaging in New Zealand. Ninety‐nine individuals (over the age of 60) in New Zealand were surveyed to determine packaging attributes of importance when selecting food products. This was followed with a focus group of 13 individuals to discuss improvements to packaging. Frequencies of responses were calculated for the survey data, and cross‐tabulations and chi‐square tests were used to determine the relationships between variables. Price, safety, size of packaging and ability to recycle were of most importance to these individuals. Problems encountered with food packaging included tight lids, small printing and spillage during opening. Of the types of package closures investigated, opening of packages, rather than resealing of packages proved problematic. Fifty percent or more of respondents indicated that peelable induction seals, lug closures and continuous thread closures were problems that occurred ‘very often’ or ‘frequently’. Sixty‐one percent of the participants surveyed had asked for assistance opening some types of packages, and this was particularly prevalent among individuals who had weakness in their arms, hands or wrists. Changes to package closures suggested during the focus groups included increasing the size of twist off caps, larger ring pulls on aluminium cans and including more sliding resealable closures on foil and plastic packaging. Larger printing on labels was also recommended by the participants. Copyright © 2008 John Wiley & Sons, Ltd. This article was published online on 1^st December 2008. An error was subsequently identified. This notice is included in the online and print versions to indicate that both were corrected on 19^th March 2009.     

The tightness of retail packaging: A selection of test methods to be used for a wide range of packed products

The tightness of retail packagings and of their closures is of primary importance both for domestic and industrial products. For this reason, a research programme designed to establish proper testing methods for a wide range of ‘packaging + product’ combinations, in order to check their tightness or permeability, was set up. All the available testing methods were reviewed, the most reliable ones selected and their sensitivity determined. More than 200 combinations of ‘packaging + product’ belonging to five families of consumer products were examined and their tightness/permeability problems noted. Finally, specific testing methods were assigned to each combination of ‘packaging + product’. All these examples are currently in use in the packaging laboratory as a guideline for the testing of every kind of packaging.     

Quality of Fresh Cut Zucchini as Affected by Cultivar,Maturity at Processing and Packaging

Appropriate plant material at processing and film packaging selection has a strong influence on product quality preservation. This is the first report studying the feasibility for minimal processing of four zucchini cultivars at two maturity stages, immature (MS1) and mature, stored at 6 °C during 10 days under different packaging conditions. The treatments consisted a 4 × 2 × 2 × 3 factorial combination of variety, maturity at processing, film packaging and storage time, including correlation studies between quality parameters. Negative effect on final quality after processing at MS1 was observed as a result of a higher respiration rate (between 15.91 and 20.12% than at mature), CO₂ production and soluble solid consumption contributing to loss of firmness, slice discolouration and less overall quality. After 10 days under 25 µm film, cv. ‘Cronos’ showed the highest values in total chlorophylls (9.03 mg/100 g FW), while slices at MS1 suffered a noticeable oxidative stress increasing the total phenolic content (cv. ‘Parador’ > ‘Amalthée’ > ‘Cronos’ > ‘Cassiope’). At the end of storage, the highest vitamin C content was observed in trays sealed with 25 µm film (more evident in cv. ‘Cronos’ at MS1). In conclusion, processing more mature zucchini and 25 µm film packaging were the most effective combination for preserving quality. Copyright © 2016 John Wiley & Sons, Ltd.     

Improvements in honeycomb abradable seals

Abstract

The concept of utilising honeycomb abradable seals to improve gas turbine engine performance has been under development for many years. Engine operating temperatures, in the region of the seals, have been restricted to below 950°C by the reliance on a chromia scale for degradation protection. The introduction of nickel brazed FeCrAlY based alloys within the honeycomb seal could facilitate a safe increase in operating temperatures to over 1100°C. This is aided by the formation of a more stable, α-alumina scale.

These Fe–20Cr–5Al–0.5Y foils, including the commercially produced variant designated MI2100, have been designed for a service lifetime of up to 24,000 hours. However, burner tests and isothermal oxidation tests in laboratory air at 1100 and 1200°C have shown them to fail after much shorter times. The major degradation of the foils occurs adjacent to the brazed region and limits the lifetime of the honeycomb seal.

Cross-sectional analysis in a scanning electron microscope of seals manufactured from MI2100 foils, after oxidation testing at 1200°C, has shown that voids form beneath the protecting α-alumina scale. In some cases, these voids are filled with silica, with some chromia present, and may be the origin of the subsequent degradation process. The results contrast with tests on free-standing thin foils (100 μm thickness) of MI2100 and other FeCrAlY alloys, where a continuous layer of chromia is formed below the alumina outer scale, once the aluminium content of the alloy drops below a critical composition. Although there is a small amount of silicon in MI2100, the main source of the high level of silicon found in the honeycombs is most likely to be the brazing alloy, since both nickel and silicon from the braze are very mobile in FeCrAlY alloys at high temperatures.

The formation and filling of voids with silica may be associated with the subsequent failure of the protective alumina scales on these brazed alloys, and this mechanism will be developed further in this paper.     

General design of the forming collar of the vertical form,fill and seal packaging machine using the finite element method

The basic part of the vertical form, fill and seal packaging machine is the forming collar. The forming collar provides the shape over which packaging film is smoothly formed at high speed into a cylindrical shape. Describing the forming collar geometry and hence its design is, however, remarkably difficult. This paper presents, for the first time, a flexible methodology for calculating the complete geometry of the film rather than the usually non‐complete collar over which the film is formed. That is, a methodology to calculate the film geometry over the collar including the seam along which the film is longitudinally sealed. The film geometry is calculated such that it has minimum deformation energy. Advantages of the proposed methodology include its great flexibility to generate collars with different configurations for different needs. Among the collar generation methods reviewed, the proposed methodology is the first that can systematically consider all collar configuration parameters such as the seam configuration, general package cross‐section, flat or straight part of the collar, collar back angle, etc. A means for obtaining the exact collar geometry is also demonstrated. This enables right‐first‐time and repeatable collar production and reduces the time and cost for producing next generation packaging machines. Copyright © 2010 John Wiley & Sons, Ltd.     

Sift‐proofness of Dangerous Goods Packagings – An Incompletely Defined Requirement

Sift‐proofness is a requirement for different types of dangerous goods packagings for solid substances according to the international Dangerous Goods Regulations. In these regulations, a sift‐proof packaging is defined as a packaging that is completely impermeable to dry contents. This means indirectly that absolutely no mass transport of solid substances is allowed. Moreover, this requirement applies both to the original filling substance and to fine solid material generated during transport. Further specifications, test conditions or tolerable limit values are not given. This is in contrast to physical principles and the usual practice in other fields of technology in which sift‐proofness is relevant. This paper shows the necessary steps for how the requirements for sift‐proofness of dangerous goods packagings can be defined more precisely. Physical basics of the term ‘sift‐proofness’ are explained. A qualitative as well as a quantitative approach is possible. In any case, it is essential to carry out appropriate vibration tests to assess the sift‐proofness. There is a need for systematical investigations of the sift‐proofness of dangerous goods packagings. Copyright © 2017 John Wiley & Sons, Ltd.     

Evaluation du coût énergétique du steak haché surgeléEstimation of power costs for producing quick-frozen minced steaks

To analyse the total energy consumption for quick-freezing, an examination has been made of the sequence of operations to which minced steak is subjected. Non-proportional ‘general energy expenses’ (heating, cleaning, lighting, services, etc) must be related to the quantity of foodstuffs produced annually in a given manufacturing plant. Another factor which arises is an ‘energy amortisation’ to take into account the equipment employed and where manufacture involves certain energy costs.The paper identifies the operations which are necessary in the manufacture of quick-frozen minced steaks: mincing, mixing, forming; quick-freezing proper (blast air tunnel); packagings (unitary packages, secondary packaging, a 10-steak carton, bulk packages, cartons containing 5 secondary boxes); storage (accepted duration: 1 month); transport (long distance: 500 km in 10 h); retail sales (glass-fronted wall cabinets, 7 days); home preservation (3 days); home preparation (electrical cookers). The study demonstrates the predominating importance, as regards energy, of packagings, retail sales and cooking.     

Innovative focused ultrasound-based sealing method of flexible packaging films—Principles and characteristics

A key process to package goods is the closure procedure. It ensures the good protection against the environment and vice versa. Ultrasonic sealing presents the advantage of converting locally ultrasound into heat, which is optimal for temperature sensitive goods. The disadvantages remain, however, the equipment cost, the noise generation, and the process sensitivity to materials. It is necessary to develop a sealing process to decrease the acquisition cost of the sealing equipment and cover a wide range of polymer films. This paper focuses on a new sealing method based on high-intensity focused ultrasound. The principles and characteristics of this process are discussed and underpinned with experimental results. Both the acoustic and thermal effects of the sealing process are summarized. A study of the process parameter impact on the seam strength in static and dynamic operating is proposed. Low-density polyethylene films with a carrier layer of bi-oriented polypropylene and polyethylene terephthalate are used. A first test bench generates point-shaped seam. The heat generation is recorded with an infrared thermography system. A second test bench, a horizontal form fill and seal machine, produces longitudinal seams. The seam quality is controlled by tensile test and tightness test. A quick heating of the polymer films is found. Point seams and longitudinal seams are successfully generated. The seams behave similarly to the ones generated with ultrasonic sealing process. However, the sealing velocity is limited to 3 m/min. This work provides a summary of the characteristics and principles of the new sealing method in packaging applications.     

Packaging dangerous goods for transport

The principle of uniformity in national and international transport regulations has now been widely recognized and implemented. Most features of the regulations are now fully operational e.g. in respect of classification, permitted packagings and maximum quantities, labelling etc. So far as packaging standards are concerned, 1990 is scheduled as the end of the transitional period. The major problem anticipated, that of the vast numbers of combination packagings needing testing and certifying, has hopefully been reduced to a level consistent with safety by the development of the UN limited quantity provisions, their adoption in the IMDG Code and the similar provisions in RID/ADR. The outstanding questions relate to air transport. Non-specification packagings have been acceptable in air transport under the transitional packaging arrangements since the ICAO Technical Instructions came into effect in 1983/84: these are often far larger in size than those covered in Chapter 15 of the UN Recommendations. As far as is known, the use of these non-specification packagings has not given rise to problems in air transport. It is hoped that the ICAO Dangerous Goods Panel will adopt practical limited quantity provisions from 31 December 1990.     

Active packaging as an opportunity to create package design that reflects the communicational,functional and logistical requirements of food products

The packaging of industrial food products is the most important means of transmitting a product's image and taste value. When the nature of its interface and its contents are the product of carefully planned imaging, the product has notable advantages in defining its image and product identity. Modern food trends dictate an ever‐increasing amount of services: The so‐called ‘functional packaging’ and ‘active packaging’ are prime examples of this service. The greatest innovation within this category of products consists literally of their interaction with food. These features create numerous fallbacks within all stages of the life‐cycle of a product, requiring a complex and multidisciplinary evaluation. The evaluation strategy of services which this packaging will offer to the consumer is still to be defined, and still to be identified within the key applications are the interests of the intermediary links of the production process. This requires the evaluation of the semantic and communicative aspects of the packaging which tend to be confused with the foodstuffs, the individualization of appropriate user profiles, control of logistical and location aspect of production, and a careful analysis of a comprehensive environmental balance, all issues that are parts of the objectives of the European project, Actipak. It is hoped, therefore, that the elaboration of these packaging systems will become a motive to try out a more knowledgeable and systematic design process for foodstuffs, in which innovative technology is used to provide effective benefits to the consumer. Copyright © 2000 John Wiley & Sons, Ltd.     

Evaluation and optimization of seal behaviour through solid contamination of heat‐sealed films

A method is presented to apply solid powder/granulate contamination (ground coffee and blood powder) in between the heat conductive seals of flexible packaging materials. A response surface method is tested and validated to optimize seal strength of heat conductive sealing with and without solid contamination. In this study, a maximal seal strength is defined as optimal. Using these methods, three typical packaging films with varying seal layer composition (metallocene linear low‐density polyethylene (LLDPE), plastomer, and sodium ionomer) are maximized towards contaminated seal strength. Contamination caused a decrease in seal strength and narrowed down the process window (seal temperature and time combinations) in which at least 90% of the maximal strength is obtained. The influence of seal layer composition on the clean and solid (ground coffee and blood powder) contaminated seal performance (seal strength, process window, and leak tightness) was evaluated. The film with the plastomer‐based seal layer outperformed the other films with respect to the width of the process window. It also reached a higher seal strength and a higher amount of leak tight seals (evaluated with the dye penetration test) after optimization. The hot tack test was evaluated as predictive test for the contaminated seal strength. The results of this study do not support an indicative relationship.     

Influence of side stripe on the corrosion of unlacquered tinplate cans for food preserves

Metal containers are used for packaging foodstuffs; more specifically, the cans used for preserving fruit have a plain body with side seam protected by a lacquer film. The traditionally used side stripe is adopted “out of abundance of caution”, as the tin present on the seam is removed by the welding process. Not using a side stripe would have practical/functional benefits for the entire production chain, with consequent reduction in the cost of the containers and in their environmental impact. Packaging of medium‐acidity products in tinplate cans is based on the principle of cathodic protection of steel by tin. To ensure that this condition persists throughout the product's shelf life, it is necessary for the anode area to be larger than the cathode area. When the seam is protected with lacquer, this condition is met. In cans where no side stripe is applied on the inner seam, the cathode area increases; this could lead to an increase in corrosion rate and consequent reduction of shelf life. However, the use of tinplate with high tin coating weight (D 11.2 g/m²) can limit this effect, under suitable packaging conditions (absence of oxygen). The aim of this study is to analyze the possibility of using cans without lacquer stripe on the electric side seam for the packaging of fruit and, more generally, of medium‐acidity products. Electrochemical measurements of model‐systems, and pack tests were used in the study.     

用于微电子机械系统封装的体硅键合技术和薄膜密封技术

对静电键合、体硅直接键合和界面层辅助键合等三种体硅键合技术，整片操作、局部操作和选择保护等三种密封技术，以及这些技术用于微电子机械系统的密封作了评述，强调在器件研究开始时应考虑封装问题，具体技术则应在保证器件功能和尽量减少芯片复杂性两者之间权衡决定。     

汽车车门密封结构的传声实验研究

汽车高速行驶时气流导致的车身内外压差和密封件局部压力变化,会使车门密封传声加剧,目前针对车门密封传声的相关研究较少.通过小型气动-声学风洞实验测试手段,参考汽车实车门结构密封和气动力作用特点,建立门单道密封和门板四周密封结构实验研究环境和试验件,研究其密封结构的传声特性.研究表明:竖向和横向密封对门板中高频传声影响较大...     

Vakuum‐Lineardurchführungen mit Magnetflüssigkeitsdichtungen

Vacuum linear feedthroughs with magnetic fluid seal A magnetic fluid sealed feedthrough is a device that transmits linear motion into a vacuum chamber with minimal frictional resistances and minimal contamination level.They are widely employed in high and ultra‐high vacuum equipment among others in semiconductor fabrication industry and robotics applications. The operating conditions of magnetic fluid seals during reciprocating motion are so different from those with rotating motion that the use of their conventional structures for reciprocating motion seals yield no good results. Analysis of sealing mechanism of magnetic fluid seal in reciprocating motion shows that the operation of these seals is affected by the carry‐over and the magnetic fluid deformation in the sealing gap, which depends on the velocity of reciprocating motion. The reduction of magnetic fluid quantity in the sealing gap,caused by the reciprocating motion of the shaft is reason of the seal failure. In the paper a short characteristic of magnetic fluid sealing technology , principle of sealing, behaviour of the ferrofluid and seal failure mechanism in the linear motion of the shaft are given. Moreover some new structure designs of vacuum linear feedthroughs with magnetic fluid seals, which have practical application value are presented.     

Minute ‘lab-on-a-chip’ relies on perfluoroelastomer micro seals

This case study briefly describes a novel application of sealing technology. It provides details of the way in which a US company is using a perfluoroelastomer seal, which has been developed in the UK, in what are termed NanoPort connections for its minute ‘lab-on-a-chip’.A US-based manufacturer of fittings, tubing and accessories for micro-scale and nano-scale analyses, Upchurch Scientific Inc, is making use of a perfluoroelastomer for micro seals, which are vital components of a range of NanoPort connections for ‘lab-on-a-chip’ applications.     

Labyrinth seals with application to turbomachinery

It is well known that there exist losses of fluid through axial and radial gaps in turbomachines, leading to less efficiency. Every 1 % decrease in leakage flow through a high‐pressure gas turbine seals would result in a 0.4 % decrease in the specific fuel consumption [1]. Last decades, a number of solutions have been applied to overcome losses of fluid through axial and radial gaps. A feasible solution is the application of labyrinth seals to act as an obstacle on the way of flow leakages. This research is targeted to attain a seal configuration that has good dynamic sealing properties, higher compliance with the shaft, simple geometry for manufacturing and maintenance. The labyrinth seal must produce significant losses of kinetic energy in order to stop leaks passing through the sealed places. It is known that the turbine shaft exhibits modal and stress loads. Also, seals must be designed to resist loads and operate at maximum efficiency. The fulfilled numerical analysis shows that the proposed geometry causes intensive reduction of leakage flow rates and thus contributes to increase in the efficiency performance of stages under consideration.     

Shape memory wire improves sealing of aircraft doors

In aviation safety, providing maximum security for door seals is a crucial part of the specification. Other factors include ease of passenger entry and egress. Such doors require opening and closing only whilst on the ground. Other types of doors are required which can be opened in flight such as weapons bay doors on military aircraft not to mention doors for the undercarriage. But present generation aircraft seals have many deficiencies. To try to overcome these shortcomings Northrop Grumman has patented a new seal based on the special characteristics of a material new to the sealing industry, that of ‘shape memory alloys’.