Life cycle cost concept of mechanical seal-

Mechanical seal life cycle cost concept

　2020-05-06　　

The life cycle cost concept of mechanical seals:

The concept of life cycle cost of mechanical seal was proposed and used by the US Department of Defense in the 1960s. After long-term practical observation, they learned that a typical weapon system operation and maintenance cost accounts for 75% of the total cost. %, thus drawing a conclusion: the basic idea of u200bu200bproduct development is to reduce the maintenance cost during the life cycle to the lowest. Although the application of life cycle cost analysis began in the military field, it is now gradually gaining recognition in civilian products, and the application field is expanding day by day.

The life cycle cost of a product refers to the sum of the initial purchase cost, installation cost, operation cost (including energy consumption cost), maintenance cost, environmental protection cost, and the final product removal and disposal cost. Vividly speaking, it is the total cost of 'from cradle to grave'.

The life cycle cost of a mechanical seal system usually includes the initial purchase cost, installation cost, operating cost (including energy consumption cost), maintenance and repair cost, shutdown and production loss cost due to seal failure, environmental protection disposal cost, waste and Recycling costs. The environmental protection disposal costs are related to the sealed medium and its auxiliary systems, because the environmental protection requirements of mechanical seal control escape are related to the nature of the sealing fluid (such as specific gravity), the type of the sealed medium and the auxiliary system of the sealing device, such as As shown in Figure 8-6.

Figure 8-6 Selection of mechanical seal type

Note: Area I-general-purpose single seal, serially arranged non-pressurized double seal, oppositely arranged pressurized double seal, applicable area with a medium specific gravity above 0.4.

Zone II-Non-pressurized double seals arranged in series, and pressurized double seals arranged oppositely. The specific gravity of the medium is in the applicable area above 0.5-0.7.

Zone III-the oppositely arranged pressurized double seal, the non-pressurized double seal of tandem cloth 3 and the leakage discharge to the closed discharge system, the medium specific gravity is above 0.4 applicable area.

Since funds have time attributes, and currencies have different interest rates at different times, there are differences in the calculation results. Therefore, the life cycle cost analysis applies the concept of net present value, considering the present value of future benefits or costs, namely

Life cycle cost analysis models mainly include parametric models, analogy models and detailed models. Among them, the parameter model is based on the historical data of the system to determine the cost variables to predict the cost of the new system; the analogy model is based on the cost of similar products or parts, adjusted according to the difference between it and the final product; the detailed model shovel is based on the product Estimate the direct costs of products or various activities based on the consumption and prices of labor hours, labor, raw materials, energy, etc., and convert indirect costs or current costs into them. In principle, the foreign detailed model is the simplest method. For simple systems, it can get an accurate cost estimate of the product; but for complex systems, it is a difficult thing and requires a certain amount of experience and knowledge accumulation.　　1128.html,

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