D&S Car Wash Systems: Car Wash Manufacturer Shines with Hydraulic
Design for “Touchless“ System:
In the early 1990s, before maturing into the
competitive, high-profile businesses we know
today, car washes were considered eyesores
and were often tucked away behind large
department stores. With little emphasis
placed on marketability, the car wash
equipment industry of the time was largely
influenced by price—a deciding factor that
would quickly change with equipment
technology. Capitalizing on new innovations
in “touchless“ technology, D&S
Manufacturing, Inc., a stainless steel carwash
manufacturer headquartered in St. Louis,
introduced the D&S 5000TM high-pressure
touchless, brushless automatic car wash—
ushering in the next generation of car wash
system designs.
When it was first introduced in 1991, the
D&S 5000 was powered by a double pump
(5.5 GPM and 1.1 GPM) hydraulic system.
Component selection, like any equipment
purchase, was driven largely by price. As
business owners began to realize the potential
profitability of the car wash, they also
began to clamor for faster wash cycles
and a better quality wash. In
response, D&S embarked on a
redesign of the D&S 5000 and in late
1993 contacted its fluid power
partner John Henry Foster Company
(JHF), a leading hydraulic and
pneumatic distributor in St. Louis.
After reviewing the criteria, JHF
encouraged D&S to allow them to
redesign the system using Rexroth
hydraulic components from Bosch
Rexroth Corporation’s Industrial
Hydraulics business unit. Even
though D&S had the capabilities to
manufacture and assemble its own
systems, they agreed, and JHF was on its way
from being a small parts supplier to a
complete systems solution provider.
“The D&S goal has always been to help each
car wash owner build a successful operation
and achieve the maximum potential return
on their investment,“ said Dave Benedict,
D&S CEO. “Our cooperative efforts with
John Henry Foster meshed our individual
competencies and produced incredible results
in the second generation D&S 5000. Their
design input allowed us to incorporate higher
quality Rexroth components, resulting in
better overall system performance—all while
staying within our cost parameters.“
Two-Station Manifold Cleans Up Design
Ted Cassimatis, Phil Green, and Ken Strain,
members of the JHF sales and engineering
team and contributors to the D&S 5000 redesign,
described the early hydraulic system
as a 7-1/2 HP motor and a double pump
mounted on a vertical tank. A three-station D03 manifold with standard directional valves
and sandwiches controlled the main Ushaped
gantry speed, the side spinner motor,
and the oscillator motor. When a vehicle
entered the car wash, it actuated a switch on
the tire treadle prompting the gantry to pass
over the vehicle. The gantry applied presoak
as it moved over the top of the vehicle and a
hydraulic motor operated the oscillators
during the entire cycle. When the gantry
rounded a vehicle curve to proceed down the
front or back, it would reduce speed in its
descent, while a hydraulic counterbalance
valve prevented runaway. At the bottom of
the descent, an electronic eye signaled the
gantry to back up. The gantry passed over the
vehicle, applying high-pressure wash, spot free
rinse, and optional chemicals depending on
the desired wash package.
“When we reviewed the original system
design we quickly uncovered several issues
that we knew we could remedy,“ recalled
Cassimatis, who sited several examples. The
team noted the unit ran hot and the hydraulic
motor on the gantry would sometimes stall in
extreme heat conditions. The oscillators only
needed 0.6 GPM, but were fed by a dedicated
1.1 GPM gear pump. In addition, the
customer wanted more speed on the main
gantry without increasing the motor
horsepower.
To solve these challenges, the JHF team
proposed a 7-1/2HP electric motor powering
a 6.5 GPM Rexroth gear pump and a twostation
series D03 manifold. A small custom
block on the first manifold station housed a
priority flow control valve (0.6 GPM with +/-
25 percent tuning adjustment) for the
oscillators and the balance of the flow went to
the main gantry. A relief for both circuit legs
was also incorporated. The second station
provided oil to the main gantry via a Rexroth
DO3 standard directional valve, and a kick
down relief valve reduced pressure as the
gantry went to the bottom of its stroke. JHF
observed that the unit actually slowed to an
ideal speed with the kick down relief,
eliminating the previous third station that
had solely been for slow speed actuation.
“The redesign of the D&S 5000 was faster,
simpler, higher quality and more reliable,“
summarized Benedict. He also noted that
D&S labor to assemble the system placed it
soundly within the required price range.
Cutting Cycle Time, Improving Clean
As demand in the privately owned market
grew, D&S decided to design a new touchless
system specifically for the convenience store
and oil company service station market.
Introduced at the Car Care World Expo 2002
in Chicago, the patent-pending D&S Super
5000TM car wash received rave reviews from
industry experts. Touting even faster cycle
times and higher quality washes, the new
Super 5000 is also capable of sizing a vehicle
and only traveling the distance required.
This gives a better wash on the rear of shorter
cars and shortens the entire cycle time, which
in turn increases the number of cars washed
per day. D&S also included remotely
adjustable variable speeds for each individual
pass of the car, giving the system the ability
to adjust its speed depending on the chemical
that is being applied to the car—an
adjustment that provides a better overall
wash.
When the JHF team first looked at D&S’s
wish list of variable speeds and cycle times
for the new Super 5000, it was apparent that
ramping capabilities were needed to give
smooth acceleration and deceleration for the
carriage and gantry movements. Given a high inertial non-overrunning load and only
one function operating at a time, JHF chose a
Rexroth fixed gear pump system and
proportional throttle valve for bleed-off speed
control of the carriage and gantry. The
proportional valve allows the Super 5000 to
attain higher speeds without abrupt starts
and stops and with an infinite number of
speeds for presoak, high-pressure wash, spotfree
rinse and optional chemicals.
“The Rexroth proportional throttle valve was
really the key to the Super 5000 project,“ said
Cassimatis. “It made the infinite number of
speeds possible, while keeping the system
simple with only one proportional valve to
control both the carriage and the gantry
functions. Car wash owners can adjust each
pass to their own preference with the ultimate
in speed and flexibility.“
Other fixed-speed functions—side spinners,
oscillators, and optional side blasters—are fed
by a priority flow control valve and each
function has manual independent speed
control. These features, as well as other new
engineering changes, reduced the cycle time
by up to 30 percent depending on the size of
the vehicle. JHF also designed a custom
manifold to incorporate all valving and
organize the system piping with fewer
connections, fewer leak points and easier
access, all in a smaller, lightweight package.
Reflected Benedict: “With many distributors
you specify parts and you get a price. But
from day one, JHF expressed a sincere desire
to truly collaborate with us and to bring
together both our areas of industry expertise.
JHF has set a standard for us when we select
all of our suppliers. You may even here
someone say, ’We need another JHF’.“
About Us
