Pump as a rotating machinery, the shaft and the pump casing must leave a gap between, in order to prevent the liquid from the pump or air leakage into the pump (the entrance for the vacuum situation), the shaft and the pump casing is generally provided with a shaft seal . In recent years due to the continuous development of high temperature and high pressure pump, the sealing problem has become one of the important factors affecting the safety of pump. Currently used shaft seal devices generally have the following forms: packing seal, mechanical seal, labyrinth seal, floating ring seal, and for many low-pressure thermal power plant water pump, the use of soft packing seal. Use asbestos, carbon fiber, PTFE resin and other materials woven into a square or round. Soft packing seal with wide use, cheap and so on. With soft-filled pump usually leaks, the general use of tight disk gland method. If invalid, it is necessary to stop the pump to replace the filler. The soft filler generally short life cycle, and the larger wear on the sleeve, which makes peacetime maintenance increases, and not economical. At this stage can use other methods to replace the use of packing it? Draw lessons from foreign experience and combined with the actuality of China's thermal power plant, packing filler injection method can be used instead of packing. Filler gun The principle of injecting a soft packing is to inject the soft clay filler into the packing chamber of the pump with a higher pressure to replace the rope packing. The other parts of the stuffing box remain unchanged. 1 transformation steps As the low-pressure thermal power plant at this stage multi-purpose packing seal, which is facing a how to transform the original basis, based on experience, are summarized as follows. 1.1 clean up the packing room before the reform thoroughly clean the original packing room of the pump, do not allow any impurities and dirt. If the water ring, can not be abandoned. This work must be uncovered, in order to save time and materials, it is best to carry out the pump overhaul. This will allow overhauls and remodeling synchronization. 1.2 pump cover drilling In order to inject filler, the cap must be installed on the injection hole connector. The connector must be specially machined. The thread should be matched with the stuffing gun connector, and the connector gland should be machined. For the water pump with water seal, the water sealing tube can be removed and drilled and tapped directly on the water seal. 1.3 plus packing root In order to prevent packing leakage and internal leakage, before and after the packing room to be installed at both ends of each packing, you can add carbon fiber packing or PTFE packing. Because it is uncovered after the addition of packing roots, so add packing must pay attention to the gap with the root should be close. 1.4 plus filler first stuffing packing into the packing room, not too tight. Then close the pump cover, bring together the packing gland, and then fill the filler gun can be injected into the pressure. At this point the packing should be tight. 2 Matters needing attention According to Neijiang white horse power plant on the pump of such transformation and maintenance experience, should pay attention to the following items. 2.1 Renovation can only be carried out on the positive pressure pump as in the negative pressure pump (such as water jet pump) on the transformation, the stuffing easily sucked into the pump, at this stage the White Horse Power Plant has been transformed steam turbine plant industrial pumps, water pumps, water pumps , Some of the low-pressure pumps in the drainage and boiler plants work well. 2.2 packing gland not too tight After packing packing tight packing gland not too tight, there should be some loose. This filler injection gun filler, according to gland tightness to determine whether the filler is full. Gland by the loose tight, it means that the filler has been filled. 2.3 fill test pump replacement, should be based on the leakage of filler. With the start of the pump, the filler injected only due to rotational friction, it will squeeze out part of the pump, and produce a certain gap, resulting in leakage. Immediately fill the filler until no leaks. Injection filling should be divided into several times, the action should be slow, each interval of about 5min. If the packing is too tight and smoke, you can loose the packing gland, while filling the room to pour cold water cooling. After the pump is turned for a period of time, the packing and sleeve have run in well so that they will not smoke anymore. 2.4 on the pump cover injection hole connector requirements Pump cover injection hole connector should be close together, available raw tape wound, gland should have a soft washer. After the injection pressure with the filler joints, and then close the gland. 2.5 Injection can not be too forceful The filler gun pressure is high (up to 10 MPa), so injection can not force too hard, feel the gun handle to a certain pressure. 3 Advantages Through the transformation of the pump before and after the operation of the comparison, this transformation has the following advantages. 3.1 Saving money Although more investment before the transformation (Note: the purchase of the United States made filler gun to be 10 000.00 yuan /; soft filler 6 000.00 yuan / kg), but because of its durability, but also one-time Investment, from a longer period of time, than the use of packing can save about 30% of funds. 3.2 small amount of maintenance and convenience When the pump runs less time that is a leak, the gun can be directly injected into the stuffing chamber filler, and without downtime, than the tight packing method to be convenient and effective. And such a filler to use a longer period, usually up to three months or more (continuous operation of the pump). Do not need to change the filler during operation just fill filler. 3.3 sealing effect The use of good effect, high safety, wide range of use. Due to the filler was mud, under pressure in the case of close together, so the sealing effect is good. The filler is mainly made of carbon fiber, Teflon, Kevlar and other synthetic raw materials, high wear resistance, small friction coefficient, but also has good impermeability, the protection of the sleeve is very favorable. By comparison, the use of bushings longer than double the length of the transformation. And it is not only for cold water pump, but also for hot water pump (such as hydrophobic pump), and for different sizes of pumps. At this stage, most single-stage cantilever centrifugal pumps in Guang'an Power Plant are mechanically sealed, so they can be retrofitted on low-pressure pumps such as double-suction single-stage centrifugal pumps (such as open cycle cooling water pumps), while reducing maintenance and Operators and equipment leakage point, and promote the improvement of the whole plant economic benefits.