JPH0310021A - Method for preventing explosion in stage for cooling treatment of valve for internal combustion engine internally sealed with metal sodium - Google Patents

Abstract

PURPOSE:To prevent explosion even if metal Na leaks and to assure operator's safety by subjecting a valve for an internal combustion engine internally sealed with the metal Na to a heating treatment, then sealing the water surface of the treating tank to be cooled with gaseous Ar or gaseous N2. CONSTITUTION:The water surface of the cooling treatment tank 1 is sealed with the gaseous Ar or gaseous N2 to seal and cover the water surface with the gas and to insulate the same from air at the time of subjecting the above- mentioned valve 5 for the internal combustion engine to the heating treatment, then to the cooling treatment. Since the H2 generated by the reaction of the metal Na (shown by S) leaking from the valve 5 with water is thereby prevented from abruptly reacting with O2, the explosion is prevented. The cooling time of the valve 5 is usually within several minutes and the gas sealing is merely necessitated to be executed during this time. In the figure, K denotes the coupling part of the valve 5.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a method for preventing explosions during cooling treatment after heating treatment in intake and exhaust valves for high-performance internal combustion engines.

[Conventional technology]

Conventionally, this type of valve has a structure in which metallic sodium S is sealed inside the valve body, as shown in Fig. 2, and the product is manufactured through quenching, tempering, and cooling treatment with hot water and wood (hereinafter referred to as water inside). It will be transformed into [Problem to be solved by the invention C] Normally, the joint K is hermetically welded to prevent sodium gold from leaking, but defects may occur due to poor welding during the manufacturing process before heat treatment, and inspection is required. But sometimes you don't know. Therefore, when rapidly cooling after heat treatment, one piece of foil acts as a refrigerant.
It is used twice, once with hot water at 5-50℃ and once with wood at 20-25℃. According to this water cooling, the metal sodium leaking from the valve of the defective product carefully reacts with water and air (Na + H2
0-+Na01 (+H20), and the generated hydrogen combines with oxygen and combusts explosively. Also, occasional soda (
Na that has not been converted into NaOH (NaOH) has a high possibility of scattering together with the explosive gas and causing burns to workers. Furthermore, workers who were startled by the explosion noise could cause secondary accidents, which was a major problem. To avoid this, there is a method to cover up the ignited material with sand, soda ash, tarpaulin, etc., but this contaminates the cooling tank and water, and the surrounding area of the workplace, so it will be difficult to restart cultivation. This would result in a huge amount of loss and could not be adopted. Therefore, the present invention provides a method that can be used safely to prevent explosions even if metallic sodium leaks.

[Means to solve the problem]

For this reason, the present invention makes the water surface of the cooling treatment tank incombustible when heat treating an internal combustion engine valve whose inner space is filled with metallic sodium and then cooling it. The method is to seal with inert argon gas or nitrogen gas to prevent metallic sodium from rapidly reacting with water and hydrogen. Here, the reason why argon gas or nitrogen gas is used as the gas seal is that it is a safe component even if one reaction occurs, and that it is well isolated from the air layer. Note that carbon dioxide gas was not able to sufficiently prevent explosions.

[For use]

During the cooling treatment, the water surface of the cooling treatment tank is sealed with argon gas or nitrogen gas, so that the water surface is covered with a gas seal and is isolated from the air. This prevents the hydrogen produced when the metal sodium leaking from the valve reacts with the wood from rapidly reacting with the m-element! Explosions can be prevented because E can be done. Usually, the cooling time is within a few minutes, and gas sealing only needs to be performed during that time. Furthermore, even if the gas seal is released, the hydrogen generated from the leakage of metallic sodium during the gas seal gradually dissolves and disappears as NaOH, so there is no risk of explosion.

【Example】

Yes, 1 is a steel cooling tank with 500 ml of deionized water.
It is a cc water storage. Reference numeral 2 denotes a nitrogen cylinder, to which a supply pipe 4 is connected via a pressure reducing valve 3, and its tip nozzle 4a is disposed in the air portion of the cooling tank l, facing the liquid level. The ejection pressure of nitrogen gas is 0.5 to 2.0 kg/cm3,
By discharging a small amount onto the water surface from the nozzle 4a, it was possible to seal the gas above the water surface. In the experiment 1. After heating the valve 5 which was designed to allow metallic sodium to leak out, it was immediately placed in a cooling tank l whose water surface was sealed with nitrogen gas, but no explosive combustion occurred. In addition, solid 6 made of metallic sodium in the form of granules is placed in a cooling tank!
Nitrogen gas was immediately ejected from the nozzle 4a to create a gas seal, but no ignition or combustion was observed, and the product gradually melted to become NaOH. Although nitrogen gas was used in this example, similar effects were obtained using argon gas. However, from the viewpoint of cost, it is preferable to use nitrogen gas.

【Effect of the invention】

According to the present invention, it is an excellent invention that has a great effect of preventing explosions during valve cooling processing and ensuring the safety of workers.

[Brief explanation of drawings]

FIG. 1 is a device diagram for explaining the present invention in detail, and FIG. 2 is a longitudinal sectional view of a valve for an internal combustion engine. 1: cooling tank, 2: nitrogen cylinder, 3: pressure reducing valve, 4: supply pipe, 4a: nozzle, 5: test valve, 6: solid sodium metal, S: sodium metal, K: joint. Figure 1

Claims (1)

[Claims] (1) When an internal combustion engine valve whose inner space is filled with metallic sodium is heat-treated and then cooled, the water surface of the cooling treatment tank is sealed with argon gas or nitrogen gas, so that the metallic sodium is sealed. A method for preventing explosions in the cooling process of valves for internal combustion engines filled with metallic sodium to prevent sudden reactions with water and air.