RU2064097C1 - Method for filling inner spaces with liquid filler - Google Patents

Abstract

FIELD: filling spaces of devices, such as heat-sensing temperature relay-transmitters, with filler involving pre-evacuation of air. SUBSTANCE: method involves evacuation of chamber accommodating devices dipped with their open ends in filler followed by filling them under atmospheric pressure as preliminary operation; this procedure goes on until filler level in inner spaces becomes not lower than dipping depth of open ends at atmospheric pressure; then chamber is evacuated again and space is filled up under atmospheric pressure. EFFECT: improved reliability of space filling. 1 dwg

Description

 The invention relates to mechanical engineering and can be used to fill the internal cavities of devices, in particular heat-sensitive systems of temperature sensors, temperature relays with liquid filler with preliminary removal of air.

A known method of filling the internal cavities of the device by pre-pumping air using a vacuum pump and filling the cavities with a liquid filler under pressure [I]
The disadvantages of the method are the complexity of the equipment, low productivity and the dependence of the filling results on the amount of air in the filler, which is present in almost any liquid.

There is also a method of filling the internal cavities of devices with a liquid filler, including evacuating the chamber with the devices placed in it, immersed open ends in the filler, followed by filling under atmospheric pressure [2]
The disadvantage of this method is the formation of a gas cushion in the filling device, the pressure in which depends on the specific gravity of the filler and the depth of immersion, which reduces the quality of filling.

 An object of the invention is to improve the quality of filling cavities.

 The essence of the invention lies in the fact that in a method comprising evacuating a chamber with devices placed therein, immersed open ends in a filler, followed by filling under atmospheric pressure, said filling is carried out as a preliminary and performed until the filler level in the internal cavities is not lower than the depth immersion of the open ends at atmospheric pressure, and then re-evacuate the chamber and final filling under atmospheric pressure.

 The drawing schematically shows a system that implements a method of filling the internal cavities of the devices.

 The system contains a sealed chamber 1 with liquid filler, filled capillary devices 2,3,4 and a vacuum pump (not shown) connected to the chamber 1 through the hole 5.

 The filler is poured into the chamber 1, which is hermetically closed, and the devices 2-4 are immersed into it, the internal cavities of which must be filled so that the open ends of the devices 2-4 are directed downward. The chamber 1 has an inlet 5, which allows it to suck air out of it using a vacuum pump and to pump atmospheric pressure.

The drawing indicates: P _atm atmospheric pressure, P _to - pressure inside the chamber 1 with the filled devices 2-4 and a liquid filler placed in it, P _int pressure in the internal cavities of the devices 2-4, h _{p the} immersion depth of the open end of the devices 2-4 into the filler.

In the initial state, before the immersion of devices 2-4 in the filler R _ATM R _to R _int . After immersion of the devices 2-4 in the filler to a depth of h _p as a result of the hydrostatic pressure of the liquid filler located above the open end of the devices 2-4, the pressure P _ext is determined as follows. P _VN P _k + + P _n , where P _{n is the} hydrostatic pressure of the liquid filler, the height of which is h _p .

Filling is carried out in two stages. The first stage is pre-filling. From the chamber 1, air is pumped out (P _atm > P _k ). The pressure in the internal cavities of the devices P _n will tend to the pressure inside the chamber P _to (P _n - R _to ), but will always be more by the value of P _n . Upon reaching the necessary vacuum in the chamber R _k , atmospheric pressure is pumped into the inlet 5 and thus the devices 2-4 are pre-filled, and this filling with devices 2-4 by the filler should be at least h _p , i.e., the immersion depth of the open end to the filler. In practice, when pre-filling, the required vacuum in the chamber P _k should be in absolute value no more than P _n (P _k ≅ P _n ).

The second stage is the final filling. In the initial state, before the final filling of P _atm P _to P _int , because the levels of filler inside the devices 2-4 and above the open ends will compensate each other and will not form even when the gas cushion is completely filled in the capillary device.

From the chamber we begin to pump out air (P _to <P _atm ). The liquid filler will begin to be released from the air dissolved in it. The pressure in the internal cavities of the devices P _n will tend to the pressure inside the chamber P _k (P _n -> P _k ) and after some time after the cessation of air pumping (when the necessary vacuum P _{k is reached} , at which the devices are completely filled), the camera will equalize with P _to , i.e. will be R _vn R _to . Hence P _int <P _atm . Then, atmospheric pressure is gradually injected into the inlet 5. Since the pressure in the internal cavities of the devices F _ext less than the pressure in the chamber P _k, then the liquid vehicle to fill the internal cavity devices 2-4 completely.

 The test results showed that the filling quality increased by 20% compared with the known method.

Claims (1)

 A method of filling the internal cavities of devices with a liquid filler, including evacuating the chamber with devices placed therein, immersed open ends in the filler, followed by filling under atmospheric pressure, characterized in that said filling is carried out as a preliminary and is performed until the filler level in the internal cavities is obtained below the immersion depth of the open ends at atmospheric pressure, and then re-evacuate the chamber and final filling under atmospheric pressure.