Pressure gauge what are the common faults in the operation and the reason?

Friends often use pressure gauge can be very clear, sometimes some pressure at work can appear some problems, but these problems and couldn't find the reason, according to more than 20 years of industry experience, summarizes some situation and the reason, hope to help your work! First, pressure gauge with no instructions. Reason: 1, the cut-off valve of the pressure tube not open; 2, guide pressure pipe plugging; 3, spring too much dirt deposition and blocked in the pipe joint; 4, spring pipe crack; 5, central tooth and tooth wear too much, so can't mesh two, big pointer jitter. Reason: 1, the pressure measured medium; 2, the installation position of pressure gauge. Three, gauge pressure have a beating or dull phenomenon. Reason: 1, the pointer into the surface of glass or scale friction; 2, center shaft bending; 3, two gear mesh with dirt; 4, the activities of the linkage between the fan gear and screw is not flexible. Four, after the pressure is removed, Pointers can't return to zero. Reason: 1, the pointer bending; 2, short hair spring force is insufficient; 3, pointer loose; 4, have friction drive gear. Five, the uneven pressure indication error. Reason: 1, spring tube deformation failure; 2, spring tube free end and sector gear, connecting rod transmission ratio improper adjustment. Six, transmission ratio imbalance. Seven, instructions on the low side. Reason: 1, the transmission ratio imbalance; 2, spring tube leakage; 3, pointer, or has friction transmission mechanism; 4, guide pressure pipeline leak. Eight, Pointers can't instructed to limit scale. Reason: 1, transmission ratio, small; 2, inappropriate position of movement fixed to the frame; 3, inappropriate position of spring tube welding.