Firma:              Haan und Wittmer

Modell:                         LPM 28 DD

Kommentar:     Dokumente engl.

Bases of the operation  

They here described optical particle counters use the bedding light effect for the regulation of the grain size distribution and the concentration of aerosol particles.  

Prerequisite for this method is the assumption that in the measuring volume (area in the sensor (in which the particles sucked in with air are illuminated)) always only one to measuring particle present is. This particle becomes with the light of the halogen lamp (white light) or illuminates of the laser. The intensity the under different corners from the particle of radiated bedding light, onward area for 28DD and approximately 900 for 28LD and LPM28, is measured and as size to the regulation of the particle diameter or - volume uses.  

As soon as an aerosol particle passes the measuring cell, his/its bedding light reaches on a photo element (photomultiplier or photo diode) over a collective lentil system. the here generated electronic impulse becomes reinforced and classified into a predialed size area in the data processing system. The impulses counted in a predialed span becomes push air volumes through covered on this, normally 28.3 1/min. 'this the volume 1 ccfoot/min. corresponds.  

With the evaluation of the counted particles, two concepts are used among other things, that more exact explanation requires:

- cumulatively, cumul, = the number of the particles, that are bigger than the particle diameter boasted in the respective canal,

- distributive, distr, = the number of the particles, that are bigger than the particle diameter boasted in the respective canal, but smaller than the bigger particle diameter stated in the nearest canal.

The purity classes of the pure areas are standard 209 and in VDI 2083 in the U.S. Federal defined. For the decrease of installations, it is to be heeded that the VDI-Richtlinien refer to one cubic meter of air, while the proofed-air quantity of the gauges at most 28.3 1/min. amounts to, geared for the US-norm.

Technical data

Measuring method:                                      28 DD: Bedding light onward,

                                                                  28 LD & LPM 28: Bedding light 900,

Light sources:                                              28 DD:            halogen lamp 6V/l0Watt,

                                                                  28 LD:             laser diode,

                                                                                          lambda=830 nm; P=40 mW,

                                                                  LPM28:           helium neon lasers,

                                                                                          lambda=632 nm; P=5 mW

Lifespan of the light source:                         28 DD:            approximately 2000 business hours,

                                                                  28 LD:             approximately 20000 business hours,

                                                                  LPM28:           approximately 30000 business hours,

calibration:                                                  with latex particles,

Measuring area (particle size):                     28 DD:            0.3 to 10 (20) microns,

                                                                  28 LD:             0.3 to 10 microns,

                                                                  LPM28:           0.2 to 5 microns,

Measuring sizes (8 particle sizes):                for example 0.3/0.5/0.7/1.5/2.0/3.0/5.0/10,

Maximum indicated particle number:            9 999 999

Maximum particle concentration:                 300 000 particel/mm,

Flow installment:                                         283 1/min, 2.83 1/mm, electronically regular

rinsing-time (adjustable):                              0 to 99 hours, 59 min.s and 59 sec.,

Measuring time (adjustable):                        0 to 99 hours, 59 min.s and 59 sec.,

Measurements:                                            19 cm x 37 cm x 47 (26 for 28LD) cm,

(Height x width of x depth)

Weight:                                                       LPM28: 16 kg, 28DD: 14 kg, 28LD: 11 kg

of power supply:                                         220 V AC / 50 Hz / 400 watts,

Temperature:                                              at business:       5 to 35° C,

                                                                  with storage:     -30 to 65° C,

Humidity:                                                    at business:       10 to 80 %,

(without condensation)                                 with storage,:     5 to 85 %

Interface:                                                    committees RS422/RS232 interface.

Printers:                                                      thermo printers (paper width 60 mm)

As option:

Vacuuminjector (instead of pump):          air consumption approximately 100 1/mm, 6 devoid of

Retrieval unit:                                         with 8 or 16 measuring points

Built-in diskette station:                           3,5 “; 1,44 MByte, also external possibly,

Sampling pistol:                                      with start and pump counters

Measuring tentacles:                               temp., moist, air speed., pressure,

Software:                                               PARTSOFT