FR2737301A1 - System for counting particles in a mechanical piece washing installation - has particle counter at output of degasification chamber, after counting liquid is filtered and recirculated into degasification chamber - Google Patents

Abstract

The fluid containing the particles feeds a degasification reservoir(9), containing an agitator(15), whose output(9s) feeds into a particle counter(10) connected to the input of a recirculation pump(14) whose output flows through a filter(12) which collects the particles before the fluid is returned to the reservoir(9) for degassing. The output of the pump(14) contains a sampling valve(17).

Description

DEVICE FOR COUNTING PARTICLES IN A
INSTALLATION OF WASHING OF MECHAMOUS PARTS
The invention relates to a particle counting device in an installation for washing mechanical parts.

The publication Filtration News March / April 1994 describes a particle counting device in a washing installation for a mechanical part placed in a cleaning fluid circuit whose impurities are checked.

For this purpose the rinsing liquid is collected in a hopper and transported in a circuit for detecting and measuring the number and size of the particles.

When the liquid laden with impurities circulates in the circuit, the microbubbles of air carried by the liquid pass through the counting system and are assimilated to particles. As a result, all of the measurements are substantially distorted.

The object of the invention is to remedy the aforementioned drawback and relates to a particle counting device in an installation for washing mechanical parts, this device being characterized in that the fluid loaded with particles feeds a degassing tank, the l The outlet opens into a particle counter sensor means through which the inlet flow of a recirculation pump, the outlet flow of which passes through a means for filtering and retaining particles, then returns to said degassing tank.

According to another characteristic of the device, the degassing tank carries a means for agitating the fluid.

According to another characteristic of the device, the outlet pipe of the recirculation pump carries a sampling valve.

The device thus produced has the advantage of permitting permanent degassing of the fluid and of preventing cavitation of the pump. As a result, the pump is always charged and carries a liquid free of air microbubbles. Furthermore, the fluid agitator means constituted by an auxiliary recirculation pump avoids the formation of deposits in the degassing tank, thus ensuring that all the particles are properly counted.

The particle counting device according to the invention also has the advantage of allowing manual rinsing of the part by an operator having the quality of checking and examining the part.

The device thus produced also has the advantage of facilitating the rinsing of various mechanical parts and of permanently degassing the washing fluid.

In addition, the device conveys a fluid free of air microbubbles liable to distort the counting of particles at the level of the sensor means and makes it possible to extract the particles from a part, avoiding deposits before the particles pass through the sensor means and ensures the suspension of particles and impurities in the part in a reference volume which has a controlled level of cleanliness.

Other characteristics and advantages of the invention will appear on reading the description with reference to the accompanying drawing in which: - Figure 1 is a schematic representation of the counting device
particles applied to a washing installation.

The washing installation with particle counting device as shown is located near a handling and positioning arm of a mechanical part 1 in a working enclosure 2.

The enclosure 2 is connected under a hood 16 comprising pressurizing means necessary to maintain a dust-free atmosphere in said hood 16.

A device 3 with removable nozzles is suitable for the type of washing desired.

The purified washing liquid is sucked from a main tank 4 and is brought by a pump 5 through a filter 6 to the device 3.

The washing fluid charged with particles coming from part 1 is collected in a dirt collector 7, the bottom of which carries a safety membrane for stopping particles 8 with a large particle size.

The washing fluid, freed of its large particles, feeds in accordance with the invention a closed degassing tank 9, the outlet orifice 9s of which opens into a sensor means 10 such as a sensitive photo cell. The sensor means 10 is crossed by the inlet flow of a recirculation pump 14, the outlet flow of which passes through a filtering means 12 for retaining impurities.

This filtering means 12 with high retention efficiency is located downstream of the pump 14 and makes it possible to purify the washing fluid before it returns to the degassing tank 9.

The reservoir 9 has, at the start of the washing operation, a reference volume in which the formation of microbubbles liable to distort the counting of particles is prevented. In addition, the reference volume makes it possible to define a standard level of cleanliness of the reference volume.

The washing volume introduced into the tank 9 completes the reference volume so that the device allows counting of the particles in the total capacity of the tank 9.

The washing fluid degassing tank 9 is placed between the dirt collector 7 and the sensor means 10.

The reservoir 9 further comprises an agitating means which suspends the various particles and prevents their deposition on the walls of said reservoir 9. For this purpose a stirring pump 15 constitutes a means for agitating the fluid contained in the degassing reservoir 9 in the aim of avoiding any deposit of particles on the walls of said tank 9.

The flow of fluid charged with particles is sucked in by the recirculation pump 14 and passes through the sensor means 10 by generating signals transmitted to the counter 13 for measuring the number and size of the particles.

The liquid passes at the outlet of the sensor means 10 a membrane 11 which allows the recovery of the particles and their analysis.

The flow forced by the recirculation pump 14 passes through the filtering means 12 and is returned to the reservoir 9 thereby establishing a closed circuit. This closed circuit circulation guarantees that all the particles present in the washing liquid will be removed by the filtering means 12.

Furthermore, a sampling valve 17 carried by the outlet pipe of the fluid recirculation pump 14 allows other analyzes of the liquid.

An overflow valve 18 located on the tank 9 allows the return of the rinsing fluid to the main supply tank 4 and the restoration of the reference volume.

Claims (3)

1) Particle counting device in a washing plant  mechanical parts, characterized in that the fluid charged with  particles feeds a degassing tank (9) whose orifice  outlet (9s) opens into a sensor means (10)  particles crossed by the input flow of a recirculation pump  (14) whose output flow passes through a filtering means (12) and  retaining particles then returns to said degassing tank (9). 2) counting device according to claim 1, characterized in that  that the degassing tank (9) carries an agitating means (15) of the  fluid in said reservoir (9). 3) counting device according to any one of claims 1 or  2, characterized in that the outlet pipe of the pump  recirculation (14) carries a sampling valve (17).