Causes and solutions for cavitation of NYP high viscosity insulation pump
Causes of cavitation When the liquid is at a certain temperature and the pressure is reduced to the vaporization pressure at that temperature, the liquid generates bubbles. This phenomenon of generating bubbles is called cavitation. The bubbles generated during cavitation flow to the high pressure, and their volume is reduced to collapse. Causes and solutions for cavitation of NYP high viscosity insulation pump I. Causes of cavitation phenomenon When the liquid is at a certain temperature and the pressure is reduced to the vaporization pressure at this temperature, the liquid will generate bubbles. This phenomenon of generating bubbles is called cavitation. The bubbles generated during cavitation flow to the high pressure, and their volume is reduced to collapse. This phenomenon in which the bubble disappears in the liquid due to the pressure rise is called cavitation collapse. All Protect Surface Protection Roll Plastic Floor Protector Roll,Plastic Floor Protector,Hardwood Floor Protector,Floor Covering Protection Suzhou Surface Protective New Material Technology Co.,Ltd , https://www.surfaceprotective.com
NYP high viscosity insulated pump is in operation, if the partial area of ​​the overcurrent part (usually somewhere later in the impeller blade inlet), for some reason, the absolute pressure of the pumped liquid is reduced to the liquid vaporization pressure at the current temperature, The liquid begins to vaporize there, generating a large amount of steam, forming bubbles, and when the liquid containing a large amount of bubbles passes forward through the high pressure region in the impeller, the high pressure liquid around the bubbles causes the bubbles to sharply shrink and rupture. At the same time that the bubble collapses, the liquid particles fill the cavity at a high speed, which produces a strong oil attack at this moment, and strikes the metal surface with a high impact frequency. The impact stress can reach several hundred to several. Thousands of atmospheres, the impact frequency can reach tens of thousands of times per second, and in severe cases, the wall thickness will be broken down.
The process of generating bubbles and bubble collapse in the oil pump to subject the flow components to damage is the cavitation process in the oil pump. After the cavitation of the oil pump will not only damage the overcurrent components, it will also generate noise and vibration, and the performance of the NYP high-viscosity heat preservation pump will be degraded. In severe cases, the liquid in the NYP high-viscosity heat preservation pump will be interrupted and will not work properly. .
Second, NYP high viscosity insulation pump cavitation basic relationship NYP high viscosity insulation pump cavitation conditions are determined by itself and the inhalation device. Therefore, the study of the conditions of cavitation should be considered from both itself and the inhalation device. The basic relationship of cavitation is NPSHc≤NPSHr≤[NPSH]≤NPSHa
NPSHa=NPSHr(NPSHc)——NYP high viscosity heat preservation pump starts cavitation NPSHANPSHa>NPSHr(NPSHc)——NPC high viscosity pump without cavitation type NPSHa——The NPSH of the device is also called effective NPSH. The bigger the more the less cavitation;
NPSHr——NYP high viscosity heat preservation pump NPSH, also called the necessary NPSH or inlet dynamic pressure drop, the smaller the anti-cavitation performance is, the better;
NPSHc——critical NPSH is the NPSH corresponding to the performance of the NYP high viscosity insulation pump.
[NPSH]——The allowable NPSH is the NPSH used to determine the conditions for use of NYP high viscosity insulation pumps. Usually, [NPSH]=(1.1~1.5) NPSHc.
Third, the calculation of the device NPSH NPSHa=Ps/Ïg+Vs/2g-Pc/Ïg=Pc/Ïg±hg-hc-Ps/Ïg
Fourth, measures to prevent cavitation to prevent cavitation must increase the NPSHa, so that NPSHa> NPSHr can prevent cavitation:
1. Reduce the geometric suction height hg (or increase the geometric backflow height);
2. Reduce the suction loss hc, for which you can try to increase the pipe diameter, minimize the length of the pipe, elbows and accessories;
3. Prevent long-term operation under high flow rates;
4. At the same speed and flow rate, the double-suction NYP high-viscosity heat preservation pump is adopted, which reduces the inlet flow rate and is less prone to cavitation;
5. When cavitation occurs in NYP high-viscosity heat preservation pumps, the flow rate should be reduced or reduced;
6. The NYP high viscosity insulation pump suction tank has an important impact on the NYP high viscosity insulation pump cavitation;
7. For NYP high viscosity insulated pumps operating under harsh conditions, cavitation resistant materials may be used to avoid cavitation damage.
Http://news.chinawj.com.cn Editor: (Hardware Business Network Information Center) http://news.chinawj.com.cn