JPS63131893A - Self-suction pump - Google Patents

Abstract

PURPOSE:To enable a self-suction operation to be ensured by enabling the number of rotation of a motor for driving the impeller of a self-suction pump to be controlled, and then driving the impeller at a low rotational frequency when the motor is started. CONSTITUTION:A self suction pump has an impeller 2 within its casing 1, and then, above the impeller 2 are provided an air separating chamber 3 and a resistance plate 4. The number of rotations of an electric motor can be controlled, and then, when the motor is started, the impeller 2 is driven at a low rotational frequency. Therefore, the air and water, which are transferred from the impeller 2 into the air separating chamber 3, do not perform such an action that causes the upper layer water to be pressed out of the air separating chamber 3 toward a discharge opening. Consequently, a reliable self-suction operation is made feasible.

Description

[Detailed description of the invention] "Industrial application field" The present invention relates to a self-priming pump that efficiently self-primes.

``Prior art'' A self-priming pump has an air separation chamber above the impeller for priming, and at the same time the impeller sucks in the air on the suction side, the air is separated in the air separation chamber and discharged. It is configured to be transferred to the side.

The air separation chamber that separates the air on the suction side should preferably have a large capacity and be sufficiently large in height so that the air can be effectively separated by applying water pressure to the impeller. .

However, such an air separation chamber necessarily has a large size, which has been an obstacle to downsizing the self-priming pump.

However, when the air separation chamber is made smaller in order to make the self-priming pump more compact, water and air rapidly flow from the impeller into the air separation chamber as soon as the impeller rotates, so the air cannot be separated. The water in the upper layer may be pushed out toward the discharge port and the water inside the air separation chamber may disappear.

Furthermore, when the water in the air separation chamber disappears and decreases, water pressure is no longer applied to the impeller, and furthermore, air cannot be separated well, resulting in a decrease in self-priming performance.

Therefore, it becomes necessary to supply priming water to the air separation chamber again.

As described above, when the self-priming performance deteriorates, the time required for self-priming becomes extremely long, and if the water suction height is high, water may not be pumped.

Therefore, the air separation chamber needs to be constructed large enough to maintain self-priming performance, which has been an obstacle to downsizing the self-priming pump.

"Problems to be Solved by the Invention" The present invention has been made in view of these circumstances,
``Means for Solving Problems'' The present invention aims to provide a self-priming pump that can maintain sufficient self-priming performance even in a small air separation chamber. The problem is solved by configuring the impeller to be controllable, and by configuring the impeller to be driven at a low rotational speed when starting the electric motor.

"Operation" Since the electric motor is started at a low rotational speed, it is possible to prevent water in the upper layer of air separation generated upon starting from being pushed out to the discharge side.

When the rotation speed is low, self-priming performance naturally decreases, but by protecting the priming water in the air separation chamber, when the rotation speed increases, self-priming performance improves and self-priming at high head is possible. Become.

"Embodiment" The present invention will be explained based on an embodiment shown in the drawings. FIG. 1 is a vertical cross-sectional view of a main part of a self-priming pump according to an embodiment of the present invention, and FIG. , is a diagram showing an example of starting characteristics for each electric type.

In FIG. 1, the self-priming pump is equipped with an impeller 2 inside a casing 1, and is configured to rotate by being connected to an electric motor (not shown) from the back.

An air separation chamber 3 is formed in the casing 1 above the impeller 2, and the air separation chamber 3 is equipped with a resistance plate 4 so that air can be separated well.

Further, the water intake port 5 of the impeller 2 is connected via a pipe 6 to a water source 7 such as a well.

Further, in relation to the casing 1, the impeller 2 has a circulation path formed so that some of the water in the air separation chamber 3 is returned to the water intake port 5 of the impeller 2 in order to obtain a self-priming function. .

In Figure 2, at the initial stage of starting the electric motor, the rotation speed gradually increases to 1.600 rotations/minute in about 0.5 seconds, and then roughly increases to 5°OOOO rotations/minute after 90 seconds. The rotation speed is configured to increase up to 1 minute.

Such characteristics can be achieved by changing the voltage applied to the motor using the time constant of the CR timer.

Of course, a control motor can also be used.

In such a configuration, when the electric motor starts, the self-priming pump starts with the characteristics shown in Fig. 2, so the impeller 2 gradually increases its rotation speed, The air and water transferred into the air separation chamber 3 from the air separation chamber 3 do not have the effect of pushing out the water in the upper layer of the air separation chamber 3 toward the discharge port.

In other words, even if a large amount of air flows into the air separation chamber 3 at the beginning of operation, the speed will be slow because the rotation speed of the impeller 2 is low, and furthermore, a large amount of air and water will not suddenly flow in, and the rotation speed will increase. At the same time, the flow speed increases, and the priming water inside the air separation chamber 3 is protected.

After about 90 seconds, the rotational speed increases and the self-priming performance improves, making it possible to pump water even at a high head.

In order to obtain such characteristics, controlling the rotation speed as shown in FIG. The same effect can be obtained even if the impeller 2 is rotated to the normal rotation speed in a short period of about 10 seconds.

"Effects of the Invention" According to the present invention, since the rotation speed is controlled at the initial stage of startup to protect the priming water in the air separation chamber, reliable self-priming operation is possible, and problems such as replenishing priming water many times can be achieved. It is possible to obtain a self-priming pump that can eliminate this problem.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view of a main part of a self-priming pump according to an embodiment of the present invention, and FIG. 2 is a diagram showing an embodiment of starting characteristics of an electric motor. DESCRIPTION OF SYMBOLS 1... Casing, 2... Impeller, 3... Air separation seedling, 4... Resistance plate, 5... Water intake port, 6
···Piping.

Claims (1)

[Claims] In a self-priming pump having an air separation chamber above the impeller, the rotation speed of an electric motor that drives the impeller is configured to be controllable, and the impeller is configured to be driven at a low rotation speed when starting the electric motor. A self-priming pump characterized by: