Search Results for Suction rolls

Thermal spray coatings, along with certain proprietary sealants, are widely used in the paper manufacturing industry for corrosion and wear resistance and to impart special surface characteristics. This article discusses the steps involved in the paper manufacturing process. Most modern papermaking machines are based on variations of the Fourdrinier machine. The article describes four operational sections of the machine: forming, press, drying, and calendar. It provides an overview of the machine components where thermal spray coatings are used, namely, digesters, blow tanks, suction roll, center press rolls, yankee dryer rolls, calendar rolls, doctor/scalping blades, and cutting equipment.

This article reviews the failure analysis process with specific reference to the considerations that should be addressed when a casting has failed. It describes the failure analysis methodology for three failed cast components: an aluminum bracket, a bronze suction roll, and a steel automotive spindle. The article discusses failure analysis investigation by obtaining casting background information, planning the evaluation and selecting the appropriate casting for analysis, conducting a preliminary examination, conducting the proper material evaluations, and thoroughly evaluating the test data. It concludes with information on case studies that show how the methodology is adapted for differing materials, failure mechanisms, and failure circumstances.

This article discusses the methods of pulp production, pulp processing, pulp bleaching, and paper manufacturing. It describes various types of digesters, their construction materials, the corrosion problems encountered, and methods to protect these digesters from corrosion. The article examines the corrosion problems in high-yield mechanical pulping, sulfite process, neutral sulfite semichemical pulping, chemical recovery, tall oil plants, wastewater treatment, and recovery boilers. It explains the stages of chlorine-based and nonchlorine bleaching, process water reuse for elemental chlorine-free and nonchlorine bleaching stages, selection of material for bleaching equipment, developments in oxygen bleaching, and the use of highly corrosion-resistant materials for bleach plant equipment. The article reviews the materials used in the construction of paper machine components and specific corrosion problems that affect them. It discusses the composition and corrosive nature of white water. The article also addresses the corrosion and chemical recovery associated with kraft pulping liquors.

This article is an atlas of fractographs that helps in understanding the causes and mechanisms of fracture of austenitic stainless steels and in identifying and interpreting the morphology of fracture surfaces. The fractographs illustrate the following: fatigue-crack fracture, rock candy fracture, cleavage fracture, brittle fracture, high-cycle fatigue fracture, fatigue striations, hydrogen-embrittlement failure, creep crack propagation, fatigue crack nucleation, intergranular creep fracture, torsional overload fracture, stress-corrosion cracking, and grain-boundary damage of these steels. The austenitic stainless steel components include spring wires, preheater-reactor slurry transfer lines and gas lines of coal-liquefaction pilot plants, oil feed tubes and suction couch rolls of paper machines, cortical screws and compression hip screws of orthopedic implants, and Jewett nails.

This article discusses the visual and microscopic characteristics of fractures of cast alloys. These fractures include ductile rupture, transgranular brittle fracture, intergranular fracture, fatigue, and environmentally induced fracture. The article also describes the factors that affect fracture appearance.

Mechanical cleaning systems are used to remove contaminants of work surface by propelling abrasive materials through any of these three principal methods: airless centrifugal blast blade- or vane-type wheels; compressed air, direct-pressure dry blast nozzle systems; or compressed-air, indirect-suction (induction) wet or dry blast nozzle systems. This article focuses on the abrasive media, equipment, applications, and limitations of dry and wet blast cleaning. It discusses the health and safety precautions to be taken during mechanical cleaning.

Pumps and compressors are representative fluid machineries, which are indispensably important industrial equipment for water supply systems, chemical processing and reactions, and fluid power systems. This article addresses friction, lubrication, and wear of components in several types of machines such as positive displacement pumps including hydraulic pumps, turbo-pumps including centrifugal pumps, vacuum pumps, and compressors including the positive displacement type and turbo type.

This article is an atlas of fractographs that helps in understanding the causes and mechanisms of fracture of copper alloys and in identifying and interpreting the morphology of fracture surfaces. The fractographs illustrate the following: fatigue fracture, intergranular fracture, transgranular fracture, microvoid coalescence, corrosion fatigue, fatigue striations, tensile-overload fracture, stress-corrosion cracking, and pitting corrosion of these alloys.

The use of thermal spray coatings to restore worn surfaces has provided a significant improvement in surface performance due to improved wear resistance. This article discusses the general use of thermal spray coatings in reducing predominant types of wear, namely, abrasive wear, erosive wear, adhesive wear, and surface fatigue.

Metal surfaces must often be cleaned before subsequent operations to remove unwanted substances such as pigmented drawing compounds, unpigmented oil and grease, chips and cutting fluids, polishing and buffing compounds, rust and scale, and miscellaneous contaminants. The article describes common cleaning processes, including alkaline, electrolytic, solvent, emulsion, molten salt bath, ultrasonic and acid cleaning as well as pickling and abrasive blasting. It also explains how to select the appropriate process for a given soil type and surface composition.

This article begins with a description of the advantages and disadvantages of thermal spraying. It provides a discussion on the importance of substrate processing prior to coating and the role of undercutting in repair. The article reviews the steps for substrate preparation, namely, cleaning, roughening, masking, and preheating. Information on the equipment and process variables of dry abrasive grit blasting are also provided. The article describes the roles of spray stream and the spray pattern for all thermal spray processes. It discusses the defects arising from poor temperature control and from the variables influencing the manipulation of the spray torch. The article concludes with helpful information on calculating the process efficiency of thermal spraying.

This article describes the various types of press construction and the factors that influence the selection of mechanically or hydraulically powered machines for producing parts from sheet metal. Presses are broadly classified, according to the type of frame used in their construction, into two main groups: gap-frame presses and straight-side presses. The article describes the various components of mechanical presses and hydraulic presses. It discusses important factors, such as the size, force, energy, and speed requirements, that influence the selection of a press. The article describes the roles of automatic handling equipment that can be categorized as feeding equipment, unloading equipment, and transfer equipment. It concludes with information on the common types of high-production presses, such as dieing machines, multiple-slide machines, transfer presses, fine blanking presses, and flexible-die forming presses.

This article is a comprehensive collection of terms related to metalworking operations that produce shapes from forging, extrusion, drawing, and rolling operations.

This article is a compilation of definitions of the terms related to sheet metal forming and fabrication.

This article is a compilation of definition of the terms related to modeling for metals processing.