For the connecting members, the quality of each individual component before assembly, assembly accuracy and subsequent maintenance should also be considered. If the bolt pair is too long, and the general length is greater than 15 times the bolt diameter, the design should consider the connection capacity reduction problem. The surface of the coupling hole should be parallel and smooth to avoid bending stress. For studs and screw connections, the material strength of the connecting members should also be considered to determine whether high-strength grade performance fasteners are used to avoid improper matching. Use a torque wrench to properly tighten the bolts and tighten the torque to within the specified range.
Periodic inspection of high-strength bolted joints The pre-tightening force of high-strength bolts is generally in the range of elastic deformation of bolts. When the material uniformity of the connecting members is poor, local deformation may occur. This part acts as a stress relaxation effect, resulting in a connection pre- The tightening force is insufficient, so the tightening connection is generally checked and re-tightened after running for a period of time. In particular, the fastening connection used at the beginning is more necessary. A tight connection periodic inspection system can avoid failures.
When the porous fastening is connected, the fastening process is not uniform, some of the bolts have insufficient pre-tightening force, and some are overloaded and pre-tightened. The flatness of the component is out of tolerance or the bolt head and the screw are bent to make the galvanized layer of the bolt head fall off, and the bolt head is biased and supported. The preload is reduced due to thermal expansion or plastic deformation of the bolt and the clamped part. The connection is loose, and when the direction of the force changes, a gap occurs, causing an impact. Chemical attack and electrolytic erosion (rust and seizure).
The thread is not right or the fit is not good.
Service life of high-strength bolts 1) If high-strength bolts are used according to the torque specified in the instructions, these bolts can still be used as long as the screws and threads are free from damage and corrosion.
2) For important parts, such as slewing bearing bolts for building tower cranes, they should be replaced after 7 years of normal operation.
3) Any of the following defects, the bolts should be replaced.
Bolts have cracks, cracks; thread, screw damage, rust; thread wear seriously exceeds the fit clearance (sliding wire); surface decarburization, galvanized layer shedding; bending, tensile deformation; pre-tightening force does not meet the specified bolt elasticity under correct operation Deformation range, when the material uniformity of the connecting member is poor, local deformation may occur, which plays a role of stress relaxation, resulting in insufficient pre-tightening force. Therefore, the tightening connection is generally checked after running for a period of time. Pre-tighten.
The conclusion is to use high-strength bolts, which have moderate toughness and good manufacturing precision. For large-size bolted joints, the fastening method and inspection method are very important. It should be studied and accumulated in practice to achieve high-strength bolt connection. reliability.
Sulfobutyl Beta Cyclodextrin is the product thatβ-cyclodextrin 6 (also including 2, 3) OH is substituted by Sulfobutyl. It can be divided into single substitution, multiple substitution and total 6 substitutionβ-Cyclodextrin. The molecular formula is therefore different. Sulfobutyl Ether-Beta-Cyclodextrin/sulfobutyl ether-β-cyclodextrin has special affinity and inclusion for nitrogen containing. drugs.Our products including sulfobutyl ether-beta-cyclodextrin sodium salt,betadex sulfobutyl ether sodium,sulfobutyl ether-β-cyclodextrin sodium.
Product name : Sulfobutyl Ether-Beta-cyclodextrin
Appearance : white powder
Details:
Sulfobutyl Ether-Beta-cyclodextrin is used for Injection medicine, oral medicine, nasal medication and eye treatment. Sulfobutyl Ether-Beta-cyclodextrin has special affinity and inclusion for drugs containing nitrogen.
Specification of sulfobutyl beta cyclodextrin
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ITEMS |
SPECIFICATION |
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Appearance |
White to off-white solid, free from foreign matter |
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Solution Clarity |
A 30%w/v solution in water is clear and essentially free from particles of foreign matter |
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Identification (IR) |
Consistent with SBECD standard |
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Identification(Sodium) |
Identify test are positive for Sodium |
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Identification(LC) |
the retention time of the major peak of sample solution corresponds to the standard solution |
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Average Degree of Substitution |
6.2-6.9 |
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Water solution pH |
pH of 30%w/v solution in water is 5.8-6.8 |
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Heavy Metals |
≤5ppm |
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Water |
≤10% |
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β-Cyclodextrin Content |
≤0.1% |
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Sodium Chloride |
≤0.2% |
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1,4-butane sultone |
≤0.5ppm |
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4-Hydroxybutane-1-Sulfonic Acid |
≤0.09% |
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Disodium bis-(4-sulfobtyl) ether |
≤0.05% |
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Assay |
95%-105% |
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Bacterial endotoxins |
≤20EU/g |
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Microbiology |
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≤100CFU/g |
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Escherichia Coli |
Absence |
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mould plus yeast |
≤50CFU/g |
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Sulfobutyl Beta Cyclodextrin
Sulfobutyl Beta Cyclodextrin,Sulfobutyl Ether Beta Cyclodextrin,White Sulfobutyl Beta Cyclodextrin,98% Sulfobutyl Beta Cyclodextrin
Shandong Binzhou Zhiyuan Biotechnology Co., LTD , http://www.zycydextrin.com