The mixing blade assembly is powered by a 10 to 25 HP drive based on the size of the unit. The drive is integrally coupled to a right angle gearbox that drives the mixing blade. The included variable frequency drive ties directly to the drive motor for simple adjustment of high and low rotational speed of the blade.
The primary mixing gearbox is mounted directly under the floor of the mixing chamber eliminating difficult to reach and maintain seal-sets below the mixer. All chamber sealing is accomplished inside the body of the mixer. With no chains, belts, or extraneous seals to maintain, the B-Series provides greater mixing up-time and minimal preventative maintenance time.
The mixing blade can be removed from the primary rotation shaft (leaving the shaft in the mixing chamber) or the entire blade / shaft assembly can be removed together. The keyed drive shaft simply drops in from the top and is retained from the bottom side of the gearbox.
The mixing chamber is built of three primary components: a heavy wall outer body (3/4” minimum thickness) comprises the external shell. A ½” thick abrasion resistant inner lining coupled with a 1” thick abrasion resistant floor significantly reduce liner changes.
Poured urethane inner linings are available as optional components. Either the wall liner or floor liner or both can be produced from urethane.
Two massive mixing chamber doors allow easy access to both sides of the mixer allowing easy cleaning and replacement of wear parts. As required, the lid is removable for rebuild or replacement of interior liners.
- The mixer is started in low speed and the butterfly valve opens regulating sand flow into the mixing chamber.
Low speed is used during fill to minimize airborne dust. If installed, the powder feeder will feed in material during
the sand filling to ensure homogeneous dry mixing.
- The resin components are then injected utilizing low-pressure air assist. The air assist is constantly active to
ensure that the jet ports do not clog.
- Once resins are injected, the mixer accelerates to the high speed mix for the necessary mixing duration.
- After the mixing time has expired, the mixer switches to low speed and the discharge door opens. Low speed
discharge reduces slinging of mixed sand onto components outside the mixer body. Once the majority of the sand
is discharged, the mixer shifts to high speed for final emptying and the door closes.
- A small batch of scrubbing sand is introduced to the mixing chamber for cleaning at high speed. This sand will be
used as part of the next batch.
- Once the cleaning cycle is complete, the mixer shuts down until called for the next batch.
Door seal is maintained using a heavy-duty, high load air cylinder coupled with a heavy-duty linkage for positive door closure. This door sealing method is not only simple, but rugged.
The discharge chute is constructed of 1/2” thick steel with a ultra-high molecular weight polyethylene liner, preventing sticking and build-up of sand. The liner is easily replaceable for maintenance as required.
The pumping system is housed in a separate NEMA enclosure to protect he components from the plant environment. The system will consist of TWO magnetically coupled pumps. The pump motors provide consistent output RPM across the operating range.
The pumps are direct coupled to the drive motors to eliminate the inaccuracy found in chain, belt, and gear reduction couplings. The direct in-line coupling also eliminates all side load on pump bearings and packing, extending the life of the pump.
Fast response air actuated ball valves provide instant routing of chemicals to the mixing chamber.
A low-pressure air jet system provides a low CFM airflow to help introduce the chemicals into the mixing chamber and keep the mixing chamber resin ports clear. The air jet system is fully adjustable via flow controls located in the electrical enclosure.
All main electrical components are housed in a NEMA 12 dust tight disconnect enclosure. All components are thoughtfully arranged for ease of operation and maintenance.
The primary logic component is an Allen Bradley Micrologic 1000 PLC processor. The standard model offers four batch recipes, which include batch size and resin levels for all liquid and / or powder components.Batch timing is considered to be a system function and is programmable only through main system setup (not individual recipes).
As an option, Palmer Mfg. can incorporate any desired PLC that has the capability of controlling the unit. Contact our offices for your specific requirements.
A small remote enclosure is included to be located near the operator station and contains the control switches needed for automatic or hand mixer operation. In auto mode, the mixer will run when called by a bin indicator. In hand mode, the mixer will run based on a manual call signal from the operator. The wiring of this control enclosure is the responsibility of the customer.
The control system has a master safety relay with mixing door limit switch and emergency stop pushbuttons on both the machine cabinet and the operator station.
There are two modes of mixer operation:
- HAND – A manual mode of operation in which any or all aspects of the mixer are operated via two-position switches, located on the door of the enclosure.
- AUTO – All aspects of the mixer are run from a remote panel located at the operator’s station or interlocked to a core machine level indicator.
A single, three-phase electrical service is required. An internal 1-3 KVA transformer housed in the enclosure provides the
120-volt control power.
The pump circuitry consists of “soft” or programmable and scalable potentiometers or pump motor speed controllers
located in the PLC program used in conjunction with state-of-the-art Pulse-Width Modulated DC Motor Controls.
The PWM regulates motor speeds to within .5% of setpoint. The pump speed adjustment located in the HMI mounted on the door of the main electrical enclosure allows for simple, positive pump adjustments.
- Main Enclosure – Hoffman NEMA 12 Disconnect
- Main Control Components – High Quality
- Control Transformer – High Quality
- Main Voltage Requirements – 60-AMP, 480-Volt, 3-Phase, 60-HZ
- Control Voltage – 120-Volt
- Pump Drive Voltage – 0 to 90-Volt DC
B-Series Options to Consider
Fixed Volume Sand Metering System – Sand of a known and consistent density can be metered into the batch mixing system by a fixed, known volume. An upper sand flow valve opens to allow sand into a fixed volume chamber. When the
mixer calls for sand, the upper butterfly closes and the lower butterfly opens. This low cost sand metering system is the
ultimate in simplicity. Sand volume is adjusted using a variable height sand feed pipe. Accuracy is 2% or better based
Integrated Triple Load Cell Weighing System – The standard operation of the mixer uses timed fill rate. An optional,
PLC controlled three-load cell system can be installed for sand addition with accuracy of 0.5% or better.
Flo-Watch Liquid Monitoring System – This system provides positive displacement flow meters for Parts 1 and 2.
Based on the calibrated sand weight, the liquid pumps are run until the preset binder level requirements have been met.
The accuracy of these flow meters completely offsets the need for high maintenance, cumbersome, fixed volume chemical
addition cylinders. This option includes the standard resin recirculation option
Powder Feeder – This flexible hopper volumetric feeder is used to add powder materials to the mixing chamber.
Recirculating Pumps – Traditionally known for providing resins of homogeneous temperature in difficult environments, this standard option provides for high speed, air-actuated three way ball valves for the standard two pump system. Recirculation of acid cured systems is also available.
SCS Core Sand Delivery System – This option allows the mixer to remain stationary while a car delivers mixed sand to one of multiple core machines. This option also allows a batch of sand to be mixed while the shuttle car is delivering, reducing core machine waiting time. These systems are standard from Palmer Manufacturing. Advise our sales department of your exact needs for a precise quote.
Dual Discharge Doors – Dual discharge doors are available as a standard option. The second door can lead to a clean-out chute or, depending on the installation, can feed a second core machine. Doors are located 180° apart.
Mobile Batch Mixer Operation – This option is used when a single batch mixer is used to feed multiple core machines. The standard mixer is mounted to a transfer car powered by a 1-hp drive for primary motion. Generally, the PLC system that governs the transfer car is also utilized for high-end batching sequences used for individual core machines. Consult our factory for application specific costing of a mobile system.
Urethane Liner – Poured bottom and side liners area available. Either or both liners can be replaced with urethane. Liners are easily replaced and are held in place with cast-in studs nutted on the outside of the mixing chamber.
PLC Integration – All Palmer B-Series mixers come standard with PLC mixer control packages. Consult with our sales department for your exact PLC integration needs if your requirements are greater than those listed. Please note that our standard PLC upgrade package is Allen Bradley SLC 500 Series.