Cause Analysis and Countermeasures for Common Faults of Pulsating Vacuum Pressure Steam Sterilizer

1. The reason why the vacuum pump continues to work and the negative pressure does not fall.

The reason why the vacuum pump continues to suck the negative pressure does not fall:

1 The reason of the vacuum pump itself, such as the kinetic energy of the vacuum pump is reduced, the vacuum pump is reversed, etc.;

2 The total water pressure is too low, the water pressure is <0.1MPa/cm2;

3 The water flow rate is too small or the tap water pipe diameter is too thin.

Countermeasures: For the objective reasons, replace parts, such as vacuum pump, water pressure gauge, and water pipe; the sterilizer water pipe is preferably a separate pipe, and a water flow meter is installed next to the water pressure gauge to observe the water pressure and water flow rate at any time. Avoid that the water flow is too small and the negative pressure does not drop, causing the vacuum pump to dry out and the parts to be damaged.

2, sterilization temperature duration is not up to standard

Under normal conditions, the temperature of the sterilization process is 126 °C. The temperature reached 132 ° C for >4 min in 10 min, the reason:

1 The total pressure of the steam source is lower than <0.3MPa/cm2;

2 The pressure reducing valve is not sensitive and the pressure inside the sterilizer is <0.2MPa/cm2;

3 The packaging and discharge of sterilized articles are not as required. For example, the volume of the sterilization package is >30cm*30cm*50cm, and the arrangement does not affect the vapor penetration;

4 The steam has a large water content, and the vapor and water are mixed to reduce the latent heat, which affects the penetrating power and causes the sterilization to fail;

5 The surface temperature of the items to be removed in winter is low and no preheating is performed.

Countermeasure: The total steam source should be >0.4MPa/cm2, and preheat the contents of the sterilizing cabinet to fully eliminate excess water in the condensate and steam. When the interlayer pressure reaches 0.1MPa/cm2, close the interlayer drain valve and other sandwich pressure. When it reaches 0.2MPa/cm2, it will start to enter the disinfection and sterilization process. Reasonably adjust the pressure reducing valve to allow the steam to enter the sterilizing cabinet at the required pressure to prevent superheating. The pressure gauge safety valve should be calibrated once a year, and the problem should be replaced at any time. The trap should be kept open and the steam quality should be improved. To ensure that the input is clean and qualified, the saturated steam (ie, water mist ≦ 10%, air ≦ 5%), The input pipe should be set separately, the distance should not be too long, the pipe system should be wrapped with insulation material, and a filter is attached to remove impurities and dirt from the steam, and a water vapor separator is arranged to circulate the condensed water mist in the steam. The package size is suitable, longitudinally arranged, the lower part of the instrument pack is placed, the dressing pack is placed on the upper layer, and a certain gap is left between the package and the package to facilitate vapor penetration.

3, BD test failed

The pulsation vacuum steam sterilizer should be subjected to BD test before or after maintenance to detect the air removal effect of the sterilizer. If it is unqualified, the cold air is not completely removed or there is leakage in the cabinet. Start time to correct.

Reasons for BD test failure:

1 The factors of the sterilizer itself, the kinetic energy of the vacuum pump is reduced, the sterilizer is used for a long time, and the sterilizer is aging, so that the cabinet does not reach the vacuum level. The failure of the automatic control system and the shortening of the negative pressure are not conducive to the release and elimination of cold air. The sealing performance of the cabinet is degraded, and the specified negative pressure cannot be maintained, resulting in the exclusion of cold air and the infiltration of cold air. For example, the door seal is aging, and the self-locking cup has cracks.

2 technical operation factors, the size of the test package is not suitable, the cloth does not meet the requirements, the dressing is too tight, affecting the vapor penetration. The temperature rises too fast, <5min is 134°C; the total pressure of the vapor source is lower than 0.3MPa/cm2, the entry is too slow, affecting the vapor penetration, the pattern is different in depth, and the initial air temperature in the cabinet is low. Cold air is not easy to drain.

Countermeasures: For the factors of the sterilizer itself, it should be repaired immediately to ensure the working efficiency of the equipment is intact, the parameters of the instruments are working normally, the maintenance and maintenance system of the equipment is perfected, and the maintenance and monitoring are carried out regularly to strengthen the technical operation management of the staff. The BD test package is packaged according to the size of the product. The cloth type should be pure cotton cloth. It should be washed first, dried and used, but not hot. Excessive drying will affect the test results. The reusable test cloth must be washed before use. The cloth can be wetted to affect the result. The cloth towel is loosely folded. If it is too tight or the cloth bag is too small, it will not easily trap residual cold air. The BD test strip should be placed flat on the geometric center of the test bag, because the geometric center position is the slowest temperature rise after the sterilizer starts, and the cold air is the most likely to stay. The proper heating rate is controlled to gradually increase the sterilization temperature. It rises to 134 ° C for 5 min - 8 min for 3.5 min - 4 min. Preheating the test bag in the sterilizer before starting can reduce the appearance of cold air mass in the test bag.

4. The color of the chemical indicator card in the bag is abnormal.

Putting a chemical indicator card into the sterilization package is one of the valid evidences for monitoring sterilization. It is usually placed in the center of the sterilization package. Sometimes, although the sterilization temperature is >132 ° C, the duration is >4 min, the biomonitoring is acceptable, but the chemical indication The color of the card does not meet the sterilization requirements, that is, the sterilization fails, making the sterilization monitoring meaningless, or expired and humid. The sterilization chemical indicator card is in direct contact with the metal instrument or glass in the bag. Since the metal and the glass have no water absorption, the condensed water generated during sterilization tends to accumulate, soaking the indicator card in the bag, causing the indicator card to contact with excessive moisture and discoloration. An exception occurs. Even if the sterilization is successful, the meaning of monitoring will be lost.

Countermeasure: Use a qualified chemical indicator card with the correct scope of application. Place the indicator card in the center of the sterilization package. The chemical indicator card should be protected from acid and alkali, moisture and light. Place chemical indicator cards in metal and glass sterilization bags, avoid direct contact with them, and use water-proof protection measures.

The quality of hospital medical services is directly related to the sterilization effect of sterilized articles, and the sterilization effect is related to the sterilization equipment, the preparation of articles, the working attitude and technical level of the sterilizing staff. The management of all aspects of high pressure steam sterilization is the key to ensuring medical quality and reducing hospital infection. In daily work, in addition to ensuring high-pressure steam sterilization, it is necessary to ensure the quality and sterilization effect monitoring of all aspects of the preparation process before sterilization, which is also the key to ensure the sterilization effect.