New Trends in Industrial Equipment for the Improvement of Asphalt Roofing Process

Roofing techniques are the key for weather resistance and energy efficiency of buildings. Installing asphalt roofing rolls is one of the most popular roof protection methods. This is usually carried out manually. Workers apply heat to the rolls by means of burners. Operators must follow quite a few steps to roof: place the rolls on the ground, unroll, apply energy, and secure. From 20 to 25 rolls per day can be installed by an operator using this manual procedure (200–250 m2). So, the fact that manual installation means such a reduced work capacity has pushed the development of industrial equipment. Besides, requirement for reduction of CO2 emissions is forcing to develop systems that optimize the fuel consumptions or even to replace fuel burners by other types of electric heating devices. In this chapter, a review of the state of the art and market of equipment for accelerating asphalt roofing process is presented. A detailed description of some systems and patents is given. The main geometric, physical, and performance parameters will be described and compared. Two new systems based on torches and infrared heating show double installation speed that is the usual manual roofing rate

Magnetic Gearboxes for Aerospace Applications

Magnetic gearboxes are contactless mechanisms for torque-speed conversion. They present no wear, no friction and no fatigue. They need no lubricant and can be customized for other mechanical properties as stiffness or damping. Additionally, they can protect structures and mechanisms against overloads, limitting the transmitted torque. In this work, spur, planetary and "magdrive" or "harmonic drive" configurations are compared considering their use in aerospace applications. The most recent test data are summarized to provide some useful help for the design engineer

Performance of Magnetic-Superconductor Non-Contact Harmonic Drive for Cryogenic Space Applications

Harmonic drives are profusely used in aerospace mainly because of their compactness and large reduction ratio. However, their use in cryogenic environments is still a challenge. Lubrication and fatigue are non-trivial issues under these conditions. The objective of the Magnetic-Superconductor Cryogenic Non-contact Harmonic Drive (MAGDRIVE) project, funded by the EU Space FP7, is to design, build, and test a new concept of MAGDRIVE. Non-contact interactions among magnets, soft magnetic materials, and superconductors are efficiently used to provide a high reduction ratio gear that smoothly and naturally operates at cryogenic environments. The limiting elements of conventional harmonic drives (teeth, flexspline, and ball bearings) are substituted by contactless mechanical components (magnetic gear and superconducting magnetic bearings). The absence of contact between moving parts prevents wear, lubricants are no longer required, and the operational lifetime is greatly increased. This is the first mechanical reducer in mechanical engineering history without any contact between moving parts. In this paper, the test results of a −1:20 inverse reduction ratio MAGDRIVE prototype are reported. In these tests, successful operation at 40 K and 10−3 Pa was demonstrated for more than 1.5 million input cycles. A maximum torque of 3 N·m and an efficiency of 80% were demonstrated. The maximum tested input speed was 3000 rpm, six times the previous existing record for harmonic drives at cryogenic temperature

Modelling and Test of an Integrated Magnetic Spring-Eddy Current Damper for Space Applications

We present the design, manufacturing, and dynamical characterization of a mechanical suspension made by a passive magnetic spring and an eddy current damper integrated into a single device. Three configurations with 2, 3, and 4 permanent magnets axially distributed with opposite polarizations are designed, simulated, manufactured, and tested. Stiffness of 2410, 2050, 2090 N/m and damping coefficient of 5.45, 10.52 and 17.25 Ns/m are measured for the 2-, 3-, and 4-magnets configurations, respectively. The magnetic suspension provides good mechanical properties combined with excellent cleanness and high reliability, which is very desirable in mechanical systems for space applications

Towards Miniaturization of Magnetic Gears: Torque Performance Assessment

Magnetomechanical components can be a good solution in order to reduce, or even completely avoid, friction phenomena in micro-electro-mechanical systems (MEMS) since they can transmit forces through magnetic fields without contacts. In this communication, electromagnetic simulations of the expected specific torque of a coaxial magnetic gear are given. The results show that micromagnetic gears (3 mm of diameter) could provide a specific torque up to 8.98 Nm/kg, several times larger than the specific torque that microgears (<9 mm of diameter) can provide. This implies that micromagnetic gears could provide speed conversion without contact in the teeth, avoiding corresponding friction, but also that it would even improve the specific torque transmission with respect to contact microgears

Analysis of the static and dynamic behavior of a non hysteretic superconductive passive magnetic linear bearing by using an electromagnetic integral formulation

In this paper the analysis of the static and dynamic behavior of a non-hysteretic superconductive passive linear bearing is described. The high translational symmetry of the magnetic field seen by the permanent magnet assures a usable long stroke in the order of several tens of millimeters. The linear bearing in combination with an actuating system for only one degree of freedom can be used for accurate long-stroke precision positioning systems for cryogenic environments with zero hysteresis in the movement. The dynamics of the system is investigated using an integral formulation which transforms the solution of the field equations in the solution of an equivalent electric network. The knowledge of the currents in the equivalent network allows to evaluate all the electromagnetic quantities (fields, forces, eddy currents) in the system. Finally, the coupling with the equation of the rigid body permits to simulate the electro/mechanical behavior of the system with six degree of freedom (6 DOF)

Towards Miniaturization of Magnetic Gears: Torque Performance Assessment

Magnetomechanical components can be a good solution in order to reduce, or even completely avoid, friction phenomena in micro-electro-mechanical systems (MEMS) since they can transmit forces through magnetic fields without contacts. In this communication, electromagnetic simulations of the expected specific torque of a coaxial magnetic gear are given. The results show that micromagnetic gears (3 mm of diameter) could provide a specific torque up to 8.98 Nm/kg, several times larger than the specific torque that microgears (<9 mm of diameter) can provide. This implies that micromagnetic gears could provide speed conversion without contact in the teeth, avoiding corresponding friction, but also that it would even improve the specific torque transmission with respect to contact microgears

Invariance of the magnetization axis under spin reorientation transitions in polycrystalline magnets of Nd2Fe14B

A great number of useful and practical devices bene\ufb01t from the use of Nd2Fe14B magnets because of their good magnetic properties and relatively low cost. However, Nd2Fe14B presents a spin-reorientation transition (SRT) at cryogenic temperature that constitutes a challenge for engineers aiming to design devices for use in this environment. Although the spin reorientation transition is well-known for single crystals, there are very few papers describing experiments with polycrystalline samples. In this paper we show the effects of the SRT in macroscopic commercial samples, providing useful experimental data for designers. It has been proven that the macroscopic axis of magnetization in polycrystalline magnets of Nd2Fe14B remains invariant under spin reorientation transition whenever it occurs at H \ubc 0 T. However, the transverse magnetic susceptibility slightly increases after the spin reorientation transition. This makes Nd2Fe14B suitable for cryogenic applications in which permanent magnets with de\ufb01ned axis of magnetization are required