JPS59145400A - Method of manufacturing impeller for centrifugal pump - Google Patents

Abstract

PURPOSE:To prevent the sliding surface of an impeller from rusting, by carrying out such a method that a molten material at a temperature in a range of 1380 deg.C+ or -10 deg.C is poured after a mouth ring formed in the peripheral suface thereof with a plurality of stepped projections and made of gun metals, is positioned in the suction stage of the impeller which is slidingly contacted with a pump casing section. CONSTITUTION:In the process of manufacturing an impeller 1, a molten material at a temperature in a range of 1380 deg.C+ or -10 deg.C, which is determined, as a suitable temperature range, by the result of numerous experiments, is poured after a mouth ring 3 formed in the peripheral surface thereof with a plurality of stepped projections 3a, 3b... and made of gun metals is disposed in the suction stage of the impeller 1 which serves as a sliding surface with respect to a pump casing section 2. In the drawing showing the process of the casing, reference numeral 4 denotes a drag mold, 5: an upper mold, 6: a core which is set after the mouth ring 3 is disposed in the drag mold 4. The thus formed impeller 1 never rusts on the sliding surface with respect to the pump casing 2, and therefore, smooth operation may be expected even after a rest for a long time.

Description

[Detailed description of the invention] The present invention relates to a method for manufacturing an impeller of a long distance.

Conventionally, impellers for centrifugal pumps have been made of gunmetal, but recently, impellers made of steel have been proposed in order to reduce manufacturing costs. By the way, as shown in Fig. 1, such an impeller 1 often rusts on the sliding surface between the impeller suction stage P and the bomb caning 2, and if it is stopped for a long time, it may not rotate smoothly. There is a problem in that it will disappear.

The present invention aims to solve the above problems,
That is, during the manufacturing process of the impeller, a mouth ring made of gunmetal was simultaneously inserted into the impeller suction step, which becomes the sliding surface.
An example of carrying out the present invention will be described below with reference to the accompanying drawings.

FIG. 2 shows the mouth ring 3 used in the present invention, with A being a front view and B being a longitudinal sectional view.

The mouth ring 3 is made of gunmetal (bronze), and has a plurality of stepped protrusions 3a, 3b, 3c, etc. on its inner peripheral surface.
・is provided.

FIG. 3 shows the locked state, in which A is a vertical cross-sectional view of the state before hot water is poured, and B is a vertical cross-sectional view of the state after hot water is poured.

In this figure, 4 is a lower mold, 5 is an upper mold, and 6 cores. Before setting the core 6, the mouth ring 3 is placed on the lower mold 4. In addition, 7 in the drawing is a sprue.

Temperature d of hot water material 8 injected through the sprue in the present invention 1380
It is used in the range of C±1013. The above-mentioned hot water material temperature is a suitable temperature range that the present inventor has arrived at as a result of numerous experiments. Since the joint surface is not completely integrated, cracks and gaps may occur at the joint during operation, causing problems in operation. On the other hand, if it is less than 1391b, the mouth ring 3 will be exposed to a large amount during prayer, resulting in the problem that an accurate outer circumferential shape cannot be obtained.

The impeller implemented in the present invention has a diameter of 30 to 2
00 alml, and on the other hand,
The wall thickness l of the mouth ring 3 is set to 4 to 10 mm.

FIG. 4 is a usage diagram of the impeller manufactured according to the present invention.

The present invention is carried out as described above, and a part of the inner circumferential surface of the mouth ring 3 is partially molten and injected into the hot metal on the impeller body side, so that complete casting is achieved. It will not come off during actual operation, and will not cause problems such as rust on the sliding surface with the pump casing.
It can be considered a cast iron impeller that is inexpensive and has good operating performance.

[Brief explanation of the drawing]

Fig. 1 is an overall vertical cross-sectional view of the centrifugal pump, Fig. 2 shows the mouth ring used in the present invention, A is a front view, B is a vertical cross-sectional view, and Fig. 3 is a swamped state. A is a longitudinal cross-sectional view of the state before hot water is injected, B is a vertical cross-sectional view of the state after the hot water is poured, and FIG. 4 is a diagram of the use state of the impeller manufactured by the present invention. 1... Impeller 2... Bomb casing cinder 3... Mouth ring 3iz, 36, 3
c... Stepped convexity 4゛°° Lower die 5... Upper die 6... Core γ... Sprue

Claims (2)

[Claims] (1) When manufacturing the impeller of a centrifugal pump using cast iron binding, a gunmetal mouth ring is attached to the impeller suction stage that makes sliding contact with the bong casing, and the positive material temperature is set to 1.
A method for manufacturing an impeller for a centrifugal pump, characterized in that the impeller is manufactured by injecting 3sO7r+1Ot7tL7h4. (2) The method for manufacturing an impeller for a centrifugal pump according to claim 1, wherein a plurality of stepped protrusions are provided on the inner peripheral surface of the mouth ring.