Pulsator Revolutionizes Unloading
Straight International's patented pulsation control feature allows the user to:
- unload stubborn loads - successfully unloads wet, bagged, or other difficult items
- control flow - loads are stepped off the truck in amounts controlled by the operator
- increase safety - no breakaway surges, no need for operators to dislodge loads from behind
- eliminate bottlenecks - unloads more trucks in less time. Weighs and unloads over 20 trucks per hour depending on the material
- reduce costs - one man operation and faster unloading increases productivity
Why is the Pulsator a revolutionary unloader? The short answer is that it can do everything we and our customers have ever wanted an unloader to do in the forty years we have been building truck and container unloaders and it can do these things economically.
The tilting concept as patented 40 years ago is fast, smooth and dependable and has been fully proven. The addition of the pulsating component in late 1990's makes the unloader a truly universal unloader in that it can unload anything at tilt angles lower than the angle at which material will continue to slide within the truck, trailer or container. Pulsation does this and the needed tilt is reduced by a third to a half. Unloading is much safer because the lower tilt. The discharge is controlled by varying the magnitude and/or the frequency of pulsing. The response is immediate and not like reducing the tilt angle which would take several seconds and again require re-tilting. Weighing is normally important in an unloading operation and this can also be done on a Pulsator.
The Pulsator is effective because it moves the entire load horizontally in the tilted position and makes it possible to combine gravity with the force of braking or stopping horizontal movement. This imparts an unloading force to the material that can follow the slope of the tilt downward and even make the material nearly weightless. All other unloaders have fixed hinges about which the load rotates during tilting and these do not permit horizontal movement. With the Pulsator, the entire load from front to back moves several inches in the tilted position. This uniform movement is possible because of the wheel and curved track arrangement. Hydraulically braking the rearward movement combines the vertical gravity force with the horizontal motion force resulting in a force that is ideal for unloading.
Why do we say the Pulsator can unload everything? It is the braking force that adds sufficiently to the resulting (unloading) force to overcome the higher initial resistance to flow. A braking force equivalent to 1 G with a tilt of 45 degrees produces a unloading force of 1.41 G's and the material is "weightless" offering little resistance to flow within the truck. A 90 degree tilt with no pulsation produces a 1 G force and is weightless against the floor but a tilt of this magnitude is not practical. 67 degrees is considered to be a maximum by many and this produces an unloading force of 0.92 G's but the force component acting perpendicular to the tilted floor is .39 G's. With an average friction value of 0.55, the net unloading force is 0.92 - (0.39 * 0.55) or 0.71 G's. This is only half as much as we can have with the Pulsator and this is why we say the Pulsator can unload everything.