IEC60068-2-68 method La2 Step-in Dust Chamber

 https://www.pegotester.com/step-in_dust_tightness_test_chamber.html#_jcp=3_18

1. Introduction

Dustproof test chamber is designed according to IEC60529 for IP5X&IP6X tests and IEC60068-2-68 method La2 (constant air pressure), the object of this test is to determine the degree of protection against ingress of fine dust into electrotechnical products, like outdoor luminaire, household appliance, auto parts and other similar electrical products.

This is a dust tightness test in which the specimen is exposed to a heavily dust-laden air flow containing non-abrasive powder of particle size <75μm, and checking the the physical and other relevant properties of the product to provide the basis for product design, improvement and verification. The test does not simulate natural or induced environments, a vertical downwards air flow is specified for the test. Enclosures of a specified category are tested with the internal air pressure lower than the surrounding atmospheric air pressure in order to encourage the ingress of powder, the specified quantity of powder ensures that the dust concentration is extremely high and uniform. Thus, this test chamber is equipped with a dust blower device for exciting and blowing the dust into the sealed test chamber. According to the agreement and relevant regulations, the vacuum device is an optional device for IP5X test, and for IP6X and La2 testing, the test sample should be connected to a vacuum pump to pump the air inside, so that the air flow in the dust chamber can enter the sample through gaps, bushings or other similar parts; the pressure pipeline is provided with a regulating valve, a monitoring vacuum pressure gauge and a gas flow meter to measures the pumping rate. The dust falls settled at the bottom of the test box is recycled. In order to prevent the dust from adhering to the inner wall of the chamber and reduce the dust concentration, the bottom of the box is set in a funnel shape and equipped with a dust shaking device, which is convenient for dust recovery, the dust shaking cycle and the time is controlled by the central controller.

The sample volume should not exceed 25% of the internal volume of the test chamber, and the sample base should not exceed 50% of the horizontal working space surface of the test chamber. If the size of the specimen does not comply, one of the following procedures shall be applied as prescribed by the relevant specification: a). testing of individually enclosed sections of the product; b). testing of representative parts of the products comprising components such as doors, ventilating opening, seats, shaft seals etc. with the delicate parts of the product such as terminals, collector rings etc. in position at the time of testing; c). testing of smaller products having the same design details as full-scale products.

2. Features:

1). The dust chamber is mainly consisted by test chamber, funnel dust collector and control box. The test chamber will be dissembled into pieces for shipment, and the funnel dust collector and control box will be shipped as whole,  the user can self-assembly the equipment easily with the help of installation guidance.

2). The outer wall of the test chamber is made of 0.5mm thick galvanized steel plate, the inner wall is made of 0.5mm thick stainless steel plate, and lined with 75mm thick temperature stress-resistant thermal insulation materials inside. 2 observe windows are on the double hinged door, the door is sealed with double-layer silicone, and is designed to be higher than the ground guide rail, which is convenient for closing and sealing the door. The door is sealed with high tension silicone rubber sealing strip to prevent dust leakage, and there is a powder receiving tank at the lower side of the door. The chamber inside configure with lighting appliance, and a φ50mm lead hole is placed on the left side, the dust discharge port is located on the left side of the bottom of the test chamber.

3). The funnel dust collector is designed to place at the bottom, and ensure that the slope angle of the funnel is effective at a limited height 550mm, making it easier for dust to slide down to the bottom of the funnel, and avoiding the loss of dust adhesion on the inner wall of the chamber. The new design is to install a spiral feeding roller in each long funnel, through the clockwise rotation of the spiral roller, all the dust in the funnel is sent to the inlet of the high-pressure centrifugal fan on the left, and then is sent to the high-pressure centrifugal fan.The dust is pumped by centrifugal fan to the top of the test chamber to form an up and down circulation. The high-pressure centrifugal fan has low noise.

4). The control box is built-in control panel, main power circuit breaker, power distribution board, cooling fan, vacuum pipeline dust filter and high-pressure centrifugal fan.

5). The dust chamber has fault alarm function, power failure protection function, upper limit temperature protection function, timing function, self-diagnosis function.

6). Protect at power phase loss and phase sequence error, leakage, short circuit, motor over-current.