Check valve failure are generally: Gem ball or plastic gasket contaminated lead to poor sealing, showing the system pressure fluctuations. Valve can not be commutated or reversing action is slow, gas leaks, electromagnetic pilot valve failure and so on. (1) gem ball or plastic gasket contaminated lead to poor sealing. Action to be taken: Action 1: a. Open drain valve with isopropanol as mobile phase fluid. B. Remove one-way valve, place in isopropanol, and ultrasonic clean. Action 2: Remove the check valve and place in a beaker of acetone for ultrasonic cleaning. (2) The reversing valve can not change direction or change slowly, usually due to poor lubrication, the spring is stuck or damaged, oil or impurities stuck sliding parts and other causes. In this regard, should first check the work of the oil mist is normal; the viscosity of the lubricant is appropriate. If necessary, lubricate, clean the sliding part of the reversing valve or replace the spring and reversing valve. (3) After the valve is used for a long period of time, the sealing ring of the valve core is prone to wear out. The valve stem and the valve seat are damaged, resulting in gas leakage in the valve and slow or inoperative valve operation. At this point, the seals, stem and seat should be replaced or the reversing valve replaced. (4) If the electromagnetic pilot valve into the vent hole is clogged with debris and other debris, closed laxity, the activities of the core is stuck, the circuit is faulty, etc., can lead to the reversing valve can not be reversed. For the first 3 cases, clean the sludge and impurities on the pilot valve and movable iron core. The circuit failure is generally divided into two types of control circuit failure and electromagnetic coil failure. Before checking the circuit fault, the manual knob of the reversing valve should be rotated a few times to see if the reversing valve can be normally commutated under the rated pressure. If the commutation is normal, the circuit is faulty. Check, the instrument can measure the voltage of the solenoid to see if it has reached the rated voltage, if the voltage is too low, you should further check the control circuit power and the associated trip switch circuit. If the reversing valve can not be changed normally under the rated voltage, check whether the electromagnetic coil connector (plug) is loose or inaccurate. Method is, unplug the plug, measuring the resistance of the coil, if the resistance is too large or too small, indicating that the electromagnetic coil is damaged, should be replaced.

H-Beam

H-shaped steel is an economical cross-section high-efficiency section with more optimized cross-sectional area distribution and a more reasonable strength-to-weight ratio. It is named because its cross-section is the same as the English letter "H". Since all parts of the H-shaped steel are arranged at right angles, the H-shaped steel has the advantages of strong bending resistance in all directions, simple construction, cost saving and light structural weight, and has been widely used.
H-shaped steel is a widely used profile in steel structure buildings today, and it has many differences compared with I-shaped steel. The first is the flange, and second, the inner surface of the flange has no inclination, and the upper and lower surfaces are parallel. The cross-sectional properties of H-beams are significantly better than traditional I-beams, channel steels and angle steels.
The two outer and inner sides of the H-shaped steel have no slope and are straight. This makes the welding and splicing of H-beams easier than I-beams, and has better mechanical properties per unit weight, which can save a lot of materials and construction time. The section of the I-Beam is well subjected to vertical pressure and resistant to tension, but the section size cannot resist torsion because the wing plate is too narrow. H steel is the opposite, both have their own advantages and disadvantages.

H Beam,Section Steel,Shaped Steel

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