JPS6053698A - Pump casing - Google Patents

Abstract

PURPOSE:To aim at enhancing the strength of a pump casing and as well at simplify the fabrication thereof, by reducing the wall thickness of a casing nozzle which bears the total weight of the pump and a drive motor upon performance test at a factory, to such a degree that the nozzle has a final nozzle bevel shape with a finishing allowance, and by attaching radial ribs thereto. CONSTITUTION:When a pump 2 and a drive motor 3 are set on a test loop 1 upon performance test at a factory, the nozzle 6 of a pump casing 5 has to have a strength enough to bear the total weight of the pump 2 and the drive motor 3. Therefore, the wall thickness of the nozzle 6 is reduced to such a degree that it has a final nozzle bevel shape with a finishing allownace as indicated by the chain line, and radial reinforcement ribs 12 are attached to the nozzle 6 to increase the strength of the nozzle 6. Thereby, the wall thickness of the nozzle 6 may be reduced, and therefore, defects such as, for example, ingot- pipings upon casting may be hadly brought about. Further, upon final process thereof no repair weldment is necessary, and therefore, the final process may be promptly made. Accordingly, the machining steps may be reduced.

Description

Detailed Description of the Invention [Field of Application of the Invention] The present invention relates to a pump in which a suction nozzle and a discharge nozzle of a casing are welded to piping. Alternatively, the present invention relates to a cast pump casing that is used for connection with a blind lid or test loop piping when performing a factory performance test of a pump, and which is then subjected to final beveling of a flanged nozzle portion.

[Background of the invention]

The pump casing is a pressure-resistant part and must be subjected to a water pressure test or a factory performance test to confirm the performance of the pump.B It is necessary to provide flanges at the suction and discharge nozzles, especially for vertical pumps. The nozzle flange on the casing side must be bolted to the piping side flange of the test loop to support the total weight of the entire pump and drive motor.

The method of supporting the pump or motor and only connecting the test loop piping has the disadvantage that the force due to thermal expansion of the piping during high-temperature testing is applied to the support structure, and is therefore not generally used. Therefore, the wall thickness of the casing nozzle was increased to provide the strength necessary to support heavy objects, and the nozzle was then machined to the final dimensions. However, when the nozzle part is made thick, casting defects such as cavities are more likely to occur due to the difference in solidification rate during casting.

[Purpose of the invention]

The purpose of the present invention is to cast the suction nozzle and discharge nozzle portions of the casing with a wall thickness close to the final finished groove size, so that casting defects are as unlikely to occur as possible, and to maintain the casing even when the thickness decreases. During the pump factory performance test, the nozzle
An object of the present invention is to provide a pump casing having a strength capable of supporting a pump and a drive motor.

[Summary of the invention]

The nozzle part of the pump casing is connected to the test loop piping with bolts during performance tests at the pump factory, and requires strength to support the entire pump and drive motor, but increasing the thickness of the nozzle part causes casting defects such as cracks and buds. It becomes easier to do. Therefore, the nozzle wall thickness was reduced to the final groove size plus the finishing allowance, and ribs and flanges were provided radially around the nozzle periphery to improve strength and prevent casting defects from occurring.

[Embodiments of the invention]

In order to perform water pressure tests or pump factory performance tests, the pump casing must be provided with a flange at the suction or discharge nozzle to connect with a blind lid or a test loop piping flange.

Figure 1 shows the pump and drive motor installed in the test loop during the pump factory performance test. After connecting the nozzle flange 7 of the pump casing 5 to the piping side flange 4 of the test loop 1 with bolts and assembling the entire pump 2, the drive motor 3 is mounted on the pump. The casing nozzle 6 must be strong enough to support the full weight of the pump and drive motor.

Figure 2 shows the connection procedure between the pump casing nozzle and the test loop piping flange. A gasket 11 is inserted between the piping side flange 4 and the nozzle flange 7, and the nozzle flange 7 is held down by a holding ring 10 via a half holding ring 9, and tightened with bolts 8.

A sectional view of the nozzle shape of a conventional pump casing is shown in FIG. The wall thickness of the nozzle part 6 is made thicker than the final finished shape shown by the dotted line so that it has enough strength to support the pump and drive motor. This thick-walled nozzle is welded to the piping of the actual machine, so it is shipped with a beveling process, but the thicker the nozzle wall, the more likely casting defects such as cavities will occur. In order to prevent heat input and deformation, the amount of machining is reduced and radiation transmission tests are performed each time.
It was necessary to perform welding repairs at different factories and repeat liquid penetrant testing (FT), which required a large amount of man-hours in processing.

FIG. 4 shows an embodiment of the present invention, in which the wall thickness of the nozzle portion 6 is reduced to the extent that a finishing allowance is added to the final nozzle groove shape shown by the dotted line, and ribs 8 are formed radially to increase the strength of the nozzle portion. It's installed on the.

According to an embodiment of the present invention, the wall thickness of the nozzle part can be reduced, making it difficult to cause casting defects such as cavities, and in addition, ribs can be processed at once without repair welding in the final processing. This reduces the number of processing steps.

〔Effect of the invention〕

According to the present invention, the wall thickness of the nozzle portion can be reduced, and casting defects such as cavities are less likely to occur, and the reinforcing rib can be made strong enough to support the pump and the drive motor. Also, the time required for final nozzle bevel processing can be shortened since no repair welding is required for rib processing.

[Brief explanation of drawings]

Figure 1 is a diagram of the installation of the pump and drive motor in the test loop, Figure 2 is a diagram of the connection procedure between the nozzle of the pump casing and the piping side flange, Figure 3 is an explanatory diagram of the nozzle part of a conventional pump casing, and Figure 4 The figure shows an explanatory view of the nozzle part of the pump casing according to the present invention. 1...Pump performance test loop, 2...Pump, 3.
... Drive motor, 4... Test loop piping side flange,
5... Pump casing, 6... Pump nozzle, 7
...Pump nozzle fin, 8...Tightening bolt, 9
...half ring, 10...presser ring, 11...
Gasket, 1st figure 2 figure 3 figure 4

Claims (1)

[Claims] 1. For pumps that are used with casing nozzles welded to piping, the suction and discharge nozzle grooves of the casing are reinforced with ribs to reduce the wall thickness and are cast in a shape with flanges attached. A pump casing characterized by attaching a blind lid for pressure-resistant trial sales at the flange, connecting it to the test loop piping, and performing a factory performance test of the pump, and then machining the final nozzle groove. .