JPH0131083B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a partially dry underwater cutting method in which the cut portion of a workpiece is cut in a dry atmosphere during underwater cutting.

Traditionally, when underwater cutting operations are carried out using thermal cutting methods, secondary waste is generated due to the cutting, resulting in suspension of the surrounding water, making monitoring difficult during underwater cutting operations and cutting preparation operations. This often becomes a major hindrance in terms of work reliability and shortening work time.

The present invention has been made in order to solve these problems, and is a partially dry submersible method that creates a clean dry atmosphere in the cutting section of the object to be cut, and allows cutting work and preparation work to be carried out with sufficient monitoring. It is intended to provide a cutting method.

Embodiments of the partially dry underwater cutting method according to the present invention will be described below with reference to the drawings. First, to explain the structure of the apparatus for carrying out this method, a heat-resistant plastic skirt 2 in the shape of a folded bag is provided around the tip of a plasma arc cutting torch 1, which is an example of thermal cutting equipment. A gas supply nozzle 3 is provided concentrically on the outer periphery of the plasma arc cutting torch, and the bag-shaped skirt 2 is coupled to the outer circumferential surface of the tip of the gas supply nozzle 3 in communication.

Next, the partial dry underwater cutting method of the present invention using the apparatus having the above structure will be explained with reference to the drawings. When cutting an object to be cut, for example, a steel plate 4 underwater, gas is supplied from the gas supply nozzle 3 into the bag of the skirt 2. For example, a bulkhead 5 that inflates by supplying compressed air and blocks external water.
form. At the same time, compressed air is continuously supplied to the inside of the partition wall 5 so that the outside of the partition wall 5 can withstand water pressure, and the partition wall 5 is made so that it can withstand water pressure on the back side of the steel plate 4 that is the object to be cut. Increase internal pressure. In this way, the inside of the partition wall 5 becomes a dry atmosphere,
A steel plate 4 is cut by a plasma arc cutting torch 1 in a dry atmosphere, and secondary waste 6 generated during cutting is
is extruded from the cutting slit 7 to the back side of the steel plate 4 and removed, creating a clean dry atmosphere. Therefore, the steel plate 4 can be cut accurately, reliably, and easily with the plasma arc cutting torch 1 while being sufficiently monitored by an underwater lighting device, an industrial television camera, etc. (not shown) installed inside the partition wall 5. Of course, since the vicinity of the cut portion of the steel plate 4 before cutting can be maintained in a clean dry atmosphere, the cutting preparation work can be easily performed.

In the above embodiment, gas is supplied from the common gas supply nozzle 3 to the bag-shaped skirt 2 and the partition wall 5 formed by this skirt 2, but it is also possible to supply the gas separately. .

As can be seen from the above explanation, according to the partial dry underwater cutting method of the present invention, the cutting part of the object to be cut is always kept in a clean dry atmosphere, and the cutting work and its preparation work can be performed while being sufficiently monitored. Therefore, there is a great contribution to be made in improving the reliability of underwater cutting work on objects to be cut, improving cutting ability, and increasing efficiency by shortening cutting work time.

[Brief explanation of drawings]

The figure is a schematic diagram showing an embodiment of the partially dry underwater cutting method according to the present invention. 1... Plasma arc cutting torch, 2... Bag-shaped skirt, 3... Gas supply nozzle, 4... Steel plate, 5... Partition wall, 6... Secondary waste generated by cutting, 7... Cutting slit.

Claims (1)

[Claims] 1 A bag-shaped heat-resistant skirt is provided around the tip of a thermal cutting device, and when cutting an object underwater, a gas is sealed in the bag of the skirt to create a partition wall that blocks external water. A compressed gas is supplied into the partition wall from around the thermal cutting device to create a dry atmosphere near the cutting part of the object to be cut, and the object to be cut is cut with the thermal cutting device. A partially dry underwater cutting method characterized by: