Clean hall air due to burner-integrated high-vacuum exhaust system

For quite some time, the qual­i­ty of indoor air was already at an accept­able lev­el. But as a rule, it always tend­ed sharply along the max­i­mum legal require­ments. This was clear­ly too lit­tle for Aebi Schmidt Ned­er­land B.V. for the health of its employ­ees. It is true that the Nether­lands has one of the low­est work­place lim­its for pro­duc­tion plants in an inter­na­tion­al com­par­i­son any­way. But the com­pa­ny, locat­ed in Holten in the east of the coun­try, want­ed to improve air qual­i­ty in order to push the con­cen­tra­tion of haz­ardous sub­stances even fur­ther below the pre­scribed lim­it of 1 mg/m³, par­tic­u­lar­ly in the weld­ing shop.

“One focus at Aebi Schmidt was clear­ly on improv­ing work­ing con­di­tions. Air qual­i­ty was one of the cen­tral issues here.”

- Steven Koen­derink, Facil­i­ty Manager

For exam­ple, the com­pa­ny want­ed to ban haz­ardous sub­stances with lung-dam­ag­ing, tox­ic or even car­cino­genic effects — pre­cise­ly those that are pro­duced in large quan­ti­ties, espe­cial­ly in the MIG/MAG weld­ing process used to man­u­fac­ture the steel-heavy attach­ments — from pro­duc­tion alto­geth­er. Increas­ing demand in recent years had gen­er­at­ed more weld­ing work. The devel­op­ment towards becom­ing the world’s lead­ing sup­pli­er of sys­tems for clean­ing and clear­ing traf­fic areas as well as for main­tain­ing green spaces, how­ev­er, also entailed high­er demands on occu­pa­tion­al safety.

Aebi Schmidt want­ed to con­tin­ue this his­to­ry with a healthy and sat­is­fied work­force. After all, in the com­pe­ti­tion for the best minds, employ­ee health argu­ments are play­ing an increas­ing­ly impor­tant role. Clean hall air as part of the employ­er image: in the search for a sup­pli­er of extrac­tion tech­nol­o­gy, KEMPER GmbH from neigh­bor­ing Ger­many came out on top in the end. “Main­ly because of the pos­i­tive test expe­ri­ences and the com­pre­hen­sive con­sul­ta­tion in the course of our deci­sion-mak­ing,” Koen­derink looks back.

Mobile high-vacuum extraction units for flexible production

The require­ments were clear­ly defined: the clean­est pos­si­ble hall air in line with pro­duc­tion needs. Thus, on the one hand, the col­lec­tion sys­tems for the haz­ardous sub­stances gen­er­at­ed dur­ing weld­ing had to extract them effec­tive­ly and, on the oth­er hand, main­tain flex­i­bil­i­ty in pro­duc­tion. A pre­de­fined bud­get defined the frame­work for the invest­ment in occu­pa­tion­al safety.

The com­pa­ny moved along these spec­i­fi­ca­tions right from the start and put togeth­er an indi­vid­ual occu­pa­tion­al safe­ty con­cept for Aebi Schmidt. To allow for pos­si­ble adjust­ments to the weld­ing shop lay­out, the man­u­fac­tur­er relied on mobile extrac­tion units. The Ger­man com­pa­ny rec­om­mend­ed weld­ing fume extrac­tion by means of high-vac­u­um sys­tems with con­nect­ed extrac­tion burn­ers. And this due to the fol­low­ing advan­tages: first­ly, the imme­di­ate cap­ture of weld­ing fumes direct­ly at the point of ori­gin, and sec­ond­ly, the forced track­ing of the cap­ture ele­ments dur­ing welding.

As these sys­tems con­tin­ue to evolve, they are becom­ing more pop­u­lar, but to this day their rep­u­ta­tion for being dif­fi­cult to trade per­sists. Despite ini­tial skep­ti­cism, Aebi Schmidt embarked on a com­pre­hen­sive test. The real­iza­tion fol­lowed after only a few days: with­in a short time, the Vacu­Fil 250 sys­tem used had extract­ed so much weld­ing smoke that the man­u­fac­tur­er was con­vinced of its qual­i­ty. Aebi Schmidt ordered sev­er­al units at once (see also: Info on extrac­tion torches).

13 VacuFil 250 units for 26 workplaces

After the order was placed, the group deliv­ered a total of 13 Vacu­Fil 250 high-vac­u­um sys­tems to the Dutch com­pa­ny with­in a short time. Because they can each be cou­pled with two extrac­tion torch­es, Aebi Schmidt’s employ­ees are able to weld safe­ly at 26 work­sta­tions simul­ta­ne­ous­ly. The sys­tems are matched to each oth­er in terms of extrac­tion per­for­mance so that the weld­ing fumes are opti­mal­ly cap­tured with­out destroy­ing the shield­ing gas jacket.

In con­trast to oth­er cap­ture sys­tems such as extrac­tion arms, the welders auto­mat­i­cal­ly car­ry the extrac­tion sys­tem inte­grat­ed in the torch. Via an extrac­tion noz­zle in the torch, the sys­tem reli­ably extracts the haz­ardous sub­stances at the point of ori­gin. Thus, Aebi Schmidt enables both a high pro­duc­tion capac­i­ty and clean shop air for its employ­ees. Even at the high weld­ing inten­si­ty, the Vacu­Fil-250 units extract large quan­ti­ties of smoke and dust in con­tin­u­ous oper­a­tion at a max­i­mum rate of 250 m³/h — and with­out any loss of qual­i­ty, even if two employ­ees are weld­ing at the same time.

Thanks to the par­tic­u­lar­ly high fil­ter qual­i­ty pro­vid­ed by the spe­cial Kem­Tex® ePTFE fil­ter car­tridges with sur­face fil­tra­tion, the sys­tems per­ma­nent­ly sep­a­rate more than 99.9 per­cent of the cap­tured weld­ing fume par­ti­cles. Even par­ti­cles small­er than 0.1 µm have no chance of escap­ing back into the hall air after cap­ture. Anoth­er high­light dur­ing the weld­ing process: auto­mat­ic fil­ter cleaning.

This means that the welders do not have to inter­rupt their work; instead, as the fil­ter becomes sat­u­rat­ed, the haz­ardous sub­stances enter a spe­cial dis­pos­able con­tain­er with which the sys­tems are equipped. The con­tain­ers are changed with­out con­t­a­m­i­na­tion. To fur­ther save space in pro­duc­tion, Aebi Schmidt sus­pend­ed some sys­tems at rel­e­vant posi­tions in pro­duc­tion. Basi­cal­ly, how­ev­er, the com­pa­ny main­tains its flex­i­bil­i­ty to move them at any time and to use them mobile on the floor.

Additional hall ventilation for the welding robots

When it came to the occu­pa­tion­al safe­ty con­cept, Aebi Schmidt, in coop­er­a­tion with KEMPER, thought so far as to install a new hall ven­ti­la­tion sys­tem that cap­tures weld­ing fumes dur­ing auto­mat­ed weld­ing process­es and thus also pro­vides pro­tec­tion for the employ­ees. The com­pa­ny installed a push/pull room ven­ti­la­tion sys­tem in the weld­ing robot por­tal. This cap­tures the ris­ing weld­ing fumes at a height of around four meters above the equip­ment. On one side, spe­cial suc­tion open­ings cap­ture the haz­ardous sub­stances. Via an indi­vid­u­al­ly designed pipe sys­tem accord­ing to the pro­duc­tion con­di­tions at Aebi Schmidt, they reach the cen­tral Weld­Fil fil­ter sys­tem installed out­side the hall.

After sep­a­rat­ing the par­ti­cles that are haz­ardous to health, the sys­tem returns the cleaned air to the out­lets. Because these are posi­tioned a few meters away from the intake open­ings, a con­stant hor­i­zon­tal air flow is cre­at­ed that dri­ves any weld­ing fumes that have risen in the direc­tion of the intake open­ings. In addi­tion, dis­place­ment out­lets on the floor sup­port the nat­ur­al buoy­an­cy of the weld­ing fumes. By recir­cu­lat­ing the cleaned and already heat­ed air, this prin­ci­ple is also ener­gy-effi­cient. A two-way dis­trib­u­tor also allows some of the air to be dis­charged to the out­side — and at the same time fresh air is rein­tro­duced from outside.

Thanks to the com­pre­hen­sive occu­pa­tion­al safe­ty mea­sures, Aebi Schmidt esti­mates that the hall air has improved sus­tain­ably: “The air pol­lu­tion con­trol tech­nol­o­gy at the work­places and in the robot pro­tal clear­ly exceeds our expec­ta­tions,” says Koen­derink. “Our welders are very sat­is­fied with the improved air qual­i­ty. We are always amazed at how many harm­ful haz­ardous sub­stances the sys­tems actu­al­ly cap­ture when we change the dust col­lec­tion con­tain­ers.” As a result, he says, aware­ness of one’s own health while weld­ing has increased immense­ly. And after an ini­tial changeover to the new sys­tems, even han­dling the extrac­tion torch­es, which had a rep­u­ta­tion for being cum­ber­some, is now quite easy for the welders.