First, the skin-type accumulator
1. The skin capsule (capsule) has small inertia and sensitive response, and is suitable for eliminating pulsation;
2. The bladder separates the oil and gas, and the oil and gas will not mix (without rupture);
3. Easy maintenance, less auxiliary equipment, easy installation and convenient inflation.
1. The service life of the skin bag is usually not longer than the service life of the (piston type) seal, and the quality of the skin bags of different brands is very different;
2. There are many factors that lead to the rupture of the skin capsule, including the difference in the quality and life of the skin capsule, the improper operation of each step of the skin assembly, the improper operation of each step of the pre-inflation, the calculation error of the pre-inflation pressure, large temperature changes (including large seasonal temperature differences), and long-term lateral Vibration shaking, fluid corrosion, inertia impact of tiny solid impurities in the medium, etc .;
3. When the skin ruptures, it may lead to the sudden failure of the accumulator, and a large amount of mixed oil and gas may cause a system accident;
4. The skin cannot be made too large, otherwise it will affect the life of the skin. The ASME standard is generally a maximum of 60 liters, and most of Europe is 50 liters.
5. The working pressure should not be too high, the highest in China (3 times or less safety factor) is generally 31.5Mpa, and the imported skin-type accumulator (4 times safety factor) is 51.8Mpa;
6. Due to design and processing quality, when the oil is quickly released, the bacteria-type valve of many brands of capsule accumulators will be closed in advance, causing the accumulator to suddenly fail.
7. Because the material of the bladder is rubber, the strength is not high, and it cannot withstand large pressure fluctuations. Or cylinder set.
Second, the piston type accumulator
1.Usually has a longer service life than a bladder-type accumulator;
2. Compared with the skin pack replacement of the skin pack, the piston seal replacement cost is lower and the operation is simpler;
3.Easy installation, simple structure, convenient maintenance and convenient inflation;
4. Unlike the sudden failure of the skin capsule (the skin ruptures and leaks), the piston type generally has multiple seals, and even if it fails, it gradually and slowly fails (leakage). For some equipment or systems, the sudden failure of the accumulator may cause Accidents or major losses, piston-type accumulators should be used at this time;
5. The piston accumulator can be made very large. The volume of the conventional model of the imported piston accumulator can reach 760 liters, and the non-conventional model can be larger;
6. The pressure can be very high, although the domestic piston accumulator (3 times or less safety factor) can only achieve 21Mpa or 31.5Mpa, but the imported energy accumulator (4 times safety factor) can be achieved by conventional piston type 138Mpa (1380 Bar), unconventional models can be higher;
7. High temperature resistant models have more stable performance. Imported high temperature resistant piston accumulators can withstand high temperatures below 230 degrees Celsius;
8. It can withstand a large pressure fluctuation range, and is suitable for tandem cylinders or cylinder groups (largely increase the effective volume).
1. The piston is not suitable for high-frequency reciprocating movement due to the large inertia effect under low pressure, so the piston accumulator is not suitable for absorbing pulsation and high-frequency vibration under low pressure; (but others such as auxiliary power source, storage In terms of functions such as maintaining pressure, absorbing hydraulic shock, and recovering energy, the performance of the piston type and the bladder type are the same; in addition, under high pressure conditions, such as above 13Mpa, the higher the pressure, the smaller the inertia effect of the piston, Experience has shown that the use of piston accumulators at this time, especially those of small volume, can also achieve the effects of pulse reduction, vibration absorption, and noise elimination.)
2. High requirements on the machining accuracy of the inner wall of the casing and seals, otherwise it is easy to leak, and the quality of each brand is quite different; the unique design of the imported piston accumulator minimizes leakage, and is usually used continuously -5 years only need to replenish gas;
3. The accuracy of the inner wall of the housing, the sealing material, and the lubrication design will all affect the friction of the piston movement, and the quality of each brand varies greatly.
Third, the diaphragm type accumulator
1. Its weight and volume ratio is the smallest, the response is sensitive, and the low-pressure pulsation elimination effect is remarkable.
2. Small volume, generally up to 6 liters