Articles
Low Air Flow Freezes Pumps!
The primary reason for molten metal pump freezing is "slow starts." A slow-start is defined as slowly increasing the motor RPM. When a transfer pump is slow-started, the hot metal flows gradually into a cooler riser. As the metal temperature decreases, it solidifies or freezes inside the riser. This slow-start condition typically results in permanent damage and the need to rebuild the pump or at the very least replace the riser.
Expertly Optimized Solutions
High Temperature Systems, Inc. partners with melt department managers, supervisors, and engineers to craft complete solutions and solve problems that are beyond the reach of industry off-the-shelf solutions. Drawing from our standard product lines and more than 50 years of experience, we can craft solutions unique to your applications and furnace implementations. These solutions encompass aluminum, zinc and lead operations from die casting to galvanizing.
Impeller Types and Purposes
We offer three different types of impellers for many of our molten metal pumps. (The impeller is the vaned wheel that spins inside the pump base.) The impeller and its interaction with the pump base (and base volute) largely determine the performance characteristics of a given pump design.
Circulate Continuously - Transfer on Demand
The ideal solution for these furnaces would be a single compact pump that performs both the circulation function and the transfer function. Such a pump would require a mechanism to redirect the output of the pump impeller to either a circulation nozzle or a transfer riser.
Pump Installation Planning Guidelines – Part 2 – Pump Startup Scheduling
In this article, we will examine the fine detail of the pump startup scheduling and expectations.
In this article, we’ll cover pump startup scheduling. We’ll cover prerequisites before getting started, special considerations, and how to plan for contingencies when things don’t go as planned.
Small Pump Well? You need a Chameleon!
A recent survey of installed aluminum reverb furnaces found that most included a pump well only large enough for a properly sized circulation pump. With manufacturing floor space at a premium and furnace prices increasing, it is no surprise that the pump well would be kept to an absolute minimum. High Temperature Systems, Inc. long ago designed a wide range of high efficiency pumps to bring higher circulation rates to reverb furnaces with smaller pump well sizes. These pumps are well known in the industry for providing the highest flow rates with the smallest footprint.
Re-use of a Graphite Pump - Not a Warped Idea!
Unlike stainless steel pumps, graphite pumps can be quickly and easily reintroduced into the molten metal bath, and the pump will operate with the same efficiency as when removed from the melt. This capability is because graphite retains its structural and dimensional integrity while stainless steel becomes flexible and deforms at molten metal operating temperatures. Once removed from the metal bath, especially an aluminum bath, the stainless steel pump must be discarded due to excessive deformation. Molten metal pump base showing posts, shaft, shaft bearing, and base all made of graphite treated with a proprietary oxidation inhibitor process not available elsewhere.
Like a Launder, Only Better!
A launder is used to transport molten metal. The basic construction of a launder is a steel trough lined with refractory material to insulate the molten metal from the steel. (Insulating both thermally and chemically.) The molten metal will lose heat as gravity draws it down the launder. If the heat is lost too quickly, the metal will freeze in the launder. There are a number of factors that influence the rate of heat loss including:
NEVER RUN A PUMP DRY!
The molten metal IS the lubrication for the impeller and base-volute. Running the pump dry will result in damage.
Pre-Storage Pump Inspection - Maintenance Pumps
Before putting a pump away for storage, it must be inspected. This article covers the step-by-step process to take before stowing a pump.
Preparing the Pump for Storage - Operational Assessment and Removal from Metal
About 10% of pumps are used exclusively for scheduled furnace maintenance. Between usages, these pumps need to be properly stored and maintained.
Rock Catcher Basics
Rock Catchers are used to keep large chunks of material from interfering with proper pump operation. Rocks, chunks, clumps, are all terms to describe material in the melt that is a bit too large to flow through the impeller’s orifices.