MODEL 4230                                                                                                                      MODEL 230


When potential buyers visit Uniflow and see our drum melters pumping their hot melt they invariably leave impressed. That’s because they’ve witnessed our ability to pump 40% faster than competitors and have been dazzled by how our machines can cut their material waste. They know those benefits can add thousands of dollars to the bottom line and even drive revenue growth, but what they sometimes struggle with is deciding which drum melter to buy. 

In this article, we’re going to offer some pointers to help with that decision.


Hot melt applications take many different forms. Some measure requirements in hundreds of pounds per week and thousands of centipoise viscosity. Others need hundreds of pounds per hour and measure viscosity in millions of centipoise. 

Such a broad spectrum seems like it would need an extensive range of machines, but at Uniflow we need only two. These are the Model 4230 and the Model 230.

The Model 230 is undoubtedly the highest performing hot melt drum melter in the world. Important features include:

  • Works with both fiber and steel drums
  • Positive displacement gear pump for a high and stable flow rate
  • Platen power of up to 52kW for high melt rates
  • Up to 20 tons of ram force for high viscosity materials
  • PLC controls for precision and speed of set up
  • Extensive range of productivity-enhancing options      

The Model 4230 offers similar capabilities in a very affordable package. Key features are:

  • Positive displacement gear pump for high and stable flow
  • 18kW platen
  • Up to 5 tons of ram force

Where the 4230 differs most is in pumping speed. With less ram force it runs slower than the Model 230, although still 40% faster than competitor drum melters. This makes the Model 230 the clear favorite for pumping very high viscosity materials — up to 2 million centipoises. But choosing the right drum melter is about more than pump rate alone.


Every hot melter experiences a few minutes of downtime while the empty drum is swapped out. In applications like slot die coating processes, that’s a problem. To address this, Uniflow can supply both the Model 4230 and the Model 230 in tandem configurations. By putting two hot melters in parallel, flow is maintained on one while the drum is replaced on the other.

For higher throughput, there’s also the Model 2035 pressurized reservoir metering system. Using the same core technology as the Model 230 and 4230—unique platen design, gear pumps—this delivers hot melt from a pressurized reservoir for the most demanding applications.


In most cases, the fastest machine yields the highest return on investment (ROI), but that’s not always the case. Other factors to consider are:

  • Viscosity of the material being pumped
  • Material usage and cost
  • Impact on production capacity and throughput
  • Labor savings  

In most cases, the Model 4230 provides plenty of pumping capacity.  It’s only when you have extremely viscous materials or require very, very high pump rates when a Model 230 becomes necessary.


The most important decision is to go with a Uniflow. It opens the door to 40%+ higher pump rates and less material waste, plus other benefits like improved safety and consistency.

When you’re choosing between Uniflow models, the Model 4230 is the most cost effective solution in most cases.  However, if you are pumping an extremely viscous material or require an exceptional pump rate, the Model 230 may be the only choice. 

For more information on the pumping rates achieved by Uniflow drum melters on a range of hot melt materials, click below.

See Pump Rate Comparison Chart