Six-Paddle Jar Test Stirrer

What is the Six-Paddle Jar Test Stirrer?

A six-paddle jar test stirrer lowers flat paddles into six beakers at synchronized, programmable speeds to simulate coagulation and flocculation. It is used by water-treatment laboratories to select coagulant type and dose under ASTM D2035-style procedures. It is also used for sludge settling comparisons.

Overview

Unlike magnetic stirrers, a jar tester uses six vertical shafts with flat paddles, typically 25 × 75 mm, driven by a single motor and gear or belt train so that all paddles turn at the same speed. Speed is adjustable from about 10 to 300 rpm, which covers the rapid-mix stage of about 100 to 300 rpm and the slow-mix stage of about 20 to 60 rpm. Programmable models store multi-step sequences with timers, and a lighted base helps observe floc formation. Standard beakers are 1 or 2 L square-section jars that limit vortexing. The shafts can often be raised together so the beakers can be removed for settling observation. Jar testers are the conventional tool for optimizing coagulant dose, pH and mixing conditions in drinking water and wastewater treatment.

How does it work?

Multi-position stirrers use one of two drive layouts. In the shared-drive layout, a single motor rotates a belt, gear train or large magnetic array under all positions, so every vessel sees the same speed. In the independent-drive layout, each position has its own motor or electromagnet and can be set separately. Magnetic versions spin coated stir bars in flasks or vials, while paddle versions, such as jar testers, lower shafts with flat blades into beakers and control shear through speed. Heated versions add a hotplate or heating block with a temperature sensor, and some units include reflux condensers or inert gas manifolds. The key performance factor is speed uniformity between positions, which depends on drive accuracy, magnet strength and vessel alignment. Position layout influences bench space and accessibility.

What are the key features?

• Six synchronized paddles driven from one motor
• Speed range of roughly 10–300 rpm for rapid and slow mixing
• Programmable multi-step speed and time sequences
• Illuminated base for observing floc formation
• Paddles lift together for settling observation
• Square 1 or 2 L jars minimize vortexing

What are the technical specifications?

A typical six-paddle jar test stirrer configuration offers number of positions of 6, speed range of 10–300 rpm, speed accuracy of ±1 rpm, beaker volume of 1 L or 2 L, square, paddle size of 25 × 75 mm and program steps of Up to 6 speed-time steps. Values are indicative of the product class; the exact figures for each configuration are confirmed on the quotation and the calibration documents supplied with the instrument.

Which applications is it used for?

The Six-Paddle Jar Test Stirrer is used in coagulant type and dose selection, optimization of flocculation conditions, drinking water treatability testing, wastewater treatment process studies and sludge settling tests. Across the wider Multi-Position Stirrers class, laboratories also deploy it for parallel dissolution and solubility screening, liquid-liquid and solid-liquid extraction and coagulation and flocculation jar testing.

Which standards and certifications apply?

Relevant standards and methods include ASTM D2035, IEC 61010-1, IEC 61010-2-010, IEC 61326-1, USP <711>, GB/T 16881 and ISO 9001. Certification candidates for this model are CE, RoHS and ISO 9001 manufacturing; each is to be confirmed for the specific configuration before shipment, and certificates are supplied only where they have been issued.

Place the stirrer on a level, rigid bench and verify that every position is in full contact with its vessel. Check speed uniformity across positions with a tachometer during installation and at intervals, since belt wear or magnet mismatch shifts speed. Use identical vessels and stir bars in all positions to keep mixing comparable. Load positions evenly to avoid vibration. Clean spills promptly, because liquid under the plate can damage drive parts. For heated units, follow the same precautions as hotplate stirrers, including a working safety cut-out. For jar testers, follow the method for paddle geometry and beaker size, such as ASTM D2035. Keep service records and consider preventive maintenance annually.

How do I select the right Six-Paddle Jar Test Stirrer?

Select a jar tester for coagulation and flocculation studies, where paddle shear and velocity gradient are the controlled variables. It does not replace magnetic stirrers for general dissolution. State speed range, program steps, jar size, lighting and any need for speed calibration in the RFQ.

How does it compare with other Multi-Position Stirrers variants?

First set the number of positions and vessel size, since these determine the footprint and plate geometry. Decide whether all positions can share one speed, which is cheaper and adequate for dissolution or extraction, or whether each needs individual control for optimization studies. Check speed range and uniformity between positions, typically within a few percent, and maximum volume per position. If heating is needed, compare temperature range, uniformity across positions and whether a probe controls the block. For water treatment, choose a jar tester with paddle speed range suited to rapid-mix and slow-mix stages and with a lighted base if turbidity observations are made. Consider chemical resistance, hood fit, interface, and whether programmable speed steps are required. Give position count, flask sizes, speed and temperature range in the inquiry.