Low flow rate cup-type flow meter structure

1. The inductive component is the most important part of the instrument. It accepts the energy of the water flow and converts it into the rotating motion of the rotating cup.

The spiral cup (1) is made of six conical cups that are glued together with a fixed ring in a consistent direction. There is a hole in the middle of the fixing ring, which is equipped with a rotating shaft (2). The two are fixed tightly by the rotating disk and the cap (22) is made into a rotating body.

The rotating shaft (2) is the hub of the rotating mechanism. The upper end is inserted into the transmission seat (13) and contacts the agate bearing on the top; the lower end is fitted with a jewel bearing (15), and its hard and smooth socket is supported on the thimble. The tip of (20) forms a precise support system.

The upper end of the ejector pin (20) is a cone, and the tip of the needle is a very smooth spherical surface and is mounted in the middle of the plug (19). After the axial clearance is adjusted, the cap (17) is used and tightly integrated. When used, it is installed in the lower hole of the yoke to hold the jewel bearing and supports the entire load of the rotating part. The outer diameter of the head is trapped by a bell-shaped cover on the rotating shaft to form a labyrinth to prevent the intrusion of river water. After the work is completed, the ejector pin and the head must be cleaned and the instrument oil must be used to prevent the thimble from rusting. At the same time, take the rotary disk holder instead of the head installed in the lower hole of the yoke, the oil chamber of the rotary disk holder must be filled with cotton and add the instrument oil.

There is an oil chamber in the upper part of the head. When using it, the instrument oil should be filled to make the thimble and the jewel bearing work in the oil bath. In this way, not only the sensitivity of the instrument is guaranteed, but also the wear of the thimble and the jewel bearing is reduced, thereby also prolonging the service life of the instrument.

2. The role of the communication mechanism is to convert the rotation number of the rotary cup into an electric pulse signal, which is composed of a tongue tube (10) and a magnetic steel (4).

Working principle: A pair of moving contacts in the tongue tube has the dual function of magnetic conduction and electric conduction. When the magnetic steel on the rotary shaft rotates to the reed tube side, the tongue is magnetized. When the magnetic field is strong enough, the magnetic force will attract each other by overcoming the elastic force of the sheet, so that the two sheets are connected. When the magnets turn to the other side, the magnetic field weakens and the sheet is broken by its own elastic force. Therefore, each time the rotary cup rotates, the second tongue is switched on once and the counter sends a signal.

Possible failures and overcoming, avoiding methods: Magnets are too long for the tongue and the sheet is magnetized and may generate residual magnetic forces, so that the sheet does not come off even if the magnets go to the other side. At this time, the communication part can be taken out and the tongue can be returned to normal after being released from the magnetic field.

In order to avoid this phenomenon, the rotary cup position should be fixed when the instrument is packaged. This position can be checked with a counter and the rotary cup is rotated so that no signal is given.

Tongue tube sensitivity is very high, and the coordination relationship with magnet steel is very strict. When the factory each tongue tubes are very accurately assigned to the respective magnets. Therefore, the tongue tubes and magnets of different instruments cannot be interchanged, and the tongue position should not be changed.

If the tongue is damaged, the shaft and the communication component can be sent to the factory for repair.

The permanent magnets on the rotary axis must not be attracted by iron blocks (such as screwdrivers) and must not be placed close to the magnetic field. The two rotary shafts should not be put together when cleaning to avoid magnetic weakening.

The tongue life is 10 7 times at 24V and 100 mA .

Protective covers ( 3 ) are used to protect the components of the messaging mechanism and should be tightened to prevent water ingress.

3, the tail is the balance of the instrument, the flow can be measured along the axial flow of the instrument. It consists of a cross wing (24) and a counterweight (26).

When the flow rate is less than 0.1 to 0.2 m / sec, remove the counterweight mounted on the rod-to-tail (see FIG. 1).

Before the measurement, the horizontal position of the instrument should be calibrated in the local calm water. For this purpose, the counterweight (balance ring) can be adjusted.