Machine Design

Brushless washer maker finds reliability in screwless connections

Visible in this view of a LaserWash system in action is the moving boom (left) and arch hosting spray nozzles.

Spring-pressure terminals, as found on these 280 Series ground terminal blocks from Wago Corp., eliminate the need for special torque screwdrivers required for UL-approved connections on screw-terminal connections. The amount of applied torque in screw terminals depends on the individual installing the wiring. There is no such problem with dynamic clamping on spring terminals which provide gasgtight connections despite thermal cycling and vibration.

The LaserWash system from PDQ uses an infrared stop detector plus ultrasonic width, length, and height sensors to gauge vehicle dimensions. A computer then determines an optimum distance between spray nozzles and the vehicle, and moves a boom containing spray nozzles around the vehicle accordingly.

Spring-pressure terminal blocks make reliable connections for an innovative vehicle-washing system, despite temperature fluctuations and corrosive surroundings that typify commercial car washes.

PDQ Manufacturing Inc. in De Pere, Wis. (, employs M block-style terminals from Wago Corp., Germantown, Wis.(, in the control panels that run its LaserWash and SpectraWash systems. The Wago blocks use spring pressure alone to make electrical connections. Spring-pressure terminals automatically adjust to the size of the wire inserted. This eliminates concerns about loosening because of temperature cycling or vibration. And the constant dynamic pressure on the wire, plus the use of a stainless-steel spring, heads off the possibility of signal degradation from corrosion.

The Wago blocks also reduce overall wiring and maintenance time, says PDQ electrical engineer Saul Escalante. PDQ went with blocks from Germantown, Wis.-based Wago because "We are considered the leaders in brush-free technology so we only use the most reliable components," Escalante adds.

The wash system, based on a Lonworks architecture, monitors inputs from sensors and manages heaters and vector drives for ac synchronous motors. In addition, they send data over phone lines or satellites. These transmissions detail information about solution levels, equipment status, and diagnostic data that let technicians debug any problems remotely. They may also handle authorizations for credit cards.

The main mechanical components of the wash consist of a bridge, trolley, and arch, each powered by a 1-hp motor. The bridge traverses the length of the vehicle while a trolley attached to it moves from one side of the vehicle to the other. Attached to the trolley is the arch, which holds many of the spray nozzles. The arch rotates 360° around the car as the bridge and trolley trace out their moves. The spray nozzles are a special design that sweep the vehicle surface on both the leading and trailing edges, changing the angle of incidence and doubling the contact period compared to ordinary designs. The result, says PDQ, is a system that uses 45% less water than its competitors and cleans more quickly as well.

Finally, a 15-hp motor pumps all water and cleaning solutions. It works at different speeds at various stages of the wash cycle to adjust the water pressure powering the nozzles. -- Leland Teschler

Hide comments


  • Allowed HTML tags: <em> <strong> <blockquote> <br> <p>

Plain text

  • No HTML tags allowed.
  • Web page addresses and e-mail addresses turn into links automatically.
  • Lines and paragraphs break automatically.