The company that revolutionized the vacuum cleaner, Dyson Inc., has gotten the green light to go to trial with false advertising claims against rival Bissell Homecare Inc. And Bissell better hope its defense arguments fare better with the jury than they have with U.S. District Judge Samuel Der-Yeghiayan in Chicago, who sided with Dyson on several pre-trial issues on Friday.

In a 52-page summary judgment ruling, Der-Yeghiayan refused to toss Dyson's claims that Bissell overstated the respiratory benefits of its upright vacuums. He also granted Dyson summary judgment on Bissell's various affirmative defenses. Finally, he refused to block Dyson's expert witness testimony.

Dyson is the brainchild of British engineer Sir James Dyson—"the man who made vacuum cleaners sexy again," as The New Yorker put it in a 2010 profile. The company accounts for 27 percent of U.S. upright vacuum sales, despite only entering the North American market in 2002 and the $400 price-tag on its cheapest machines. Dyson's vacuums are best known for using centrifugal forces to spin out dust while keeping suction constant, but they're also marketed as being "asthma & allergy friendly."

Bissell is Dyson's chief competitor. In 2010, Bissell boasted that several of its models contain technology that "captures over 99.9 percent" of allergens like ragweed and pollen. Dyson commissioned independent testing of Bissell's vacuums. According to Dyson, the studies proved that Bissell was duping consumers. In December 2010, Dyson hired Proskauer Rose to sue Bissell. Kirkland & Ellis came aboard for Dyson a few months later.

In 2011, Bissell slapped a new disclaimer on its vacuums explaining that the filter paper it uses in its vacuums, rather than the vacuum itself, is the airtight allergen-catcher. Dyson's lawyers at Kirkland and Proskauer pressed on with their lawsuit, alleging that even with the new disclaimer Bissell's packaging is misleading. Dyson sought to back up its case with consumer surveys and lab tests.

The trio of law firms representing Bissell—Bartlit Beck Herman Pelancher & Scott; Pattishall McAuliffe Newbury Hilliard & Geraldson; and Warner Norcross & Judd—tried to end the case on summary judgment. They argued that Dyson's claims are barred by a covenant not to sue that the company entered into with Bissell in 2006 in order to gain testimony from a Bissell employee in an unrelated case. Bissell's lawyers also claimed that Dyson's consumer polls were biased and should be blocked, and that one of Dyson's expert witness has a conflict of interest because she previously consulted for Bissell.

Those defense arguments fell flat on Friday. Der-Yeghiayan ruled that Dyson's claims don't fall within the scope of the covenant not sue. Even if they did it, it would be unfair to throw out a case in which "the undisputed facts shows that Bissell's false advertising is wanton and willful," Der-Yeghiayan added, signaling his sympathy for Dyson's claims. The judge refused to disqualify the expert, noting that she's one of the leading experts in the vacuum cleaner industry and has consulted for ever major company. Finally, he refused to exclude the consumer surveys, calling them open-ended and non-leading.

"Bissell is disappointed in the opinion, but we maintain that our ads' claims are true," said Jeffrey Hall at Bartlit Beck. "We will continue to defend vigorously against Dyson's claims."

Dyson counsel David Callahan of Kirkland & Ellis declined to comment.

CORRECTION/UPDATE: Another aspect of the judge's June 14 ruling, which we ought to have mentioned, was that he granted Dyson summary judgment on part of its complaint — namely, its allegation that advertising Bissell adopted in 2010 was false. A jury trial is scheduled for September to determine the remedy to which Dyson is entitled. At a status conference on June 19, Der-Yeghiayan ordered additional briefing on Dyson's remaining substantive false advertising claims against Bissell.