I. Overview

The Marsh Funnel Viscosimeter is an instrument used for daily measurement of drilling fluid viscosity. Manufactured according to the American API standard, it determines the viscosity of drilling fluid by measuring the time taken for a fixed volume of drilling fluid to flow out of the funnel. It features a simple structure and ease of use, and is widely used in petroleum, geological exploration, and other sectors.

The viscosity and gel strength of drilling fluid are related to its rheological properties. The standard value is defined as the time required for 946 ml of standard distilled water to flow out at a temperature of 20±5°C, which is 26±0.5 seconds. The funnel body is made of sturdy and durable engineering plastic, and the precision-machined brass orifice ensures measurement accuracy.

The measurement principle of the funnel viscosimeter is to express the viscosity of drilling fluid by the time required for a certain amount of drilling fluid to flow freely under gravity from a fixed funnel. It is usually denoted in "seconds (S)". It roughly reflects the comprehensive indicators of all rheological parameters and physical properties of drilling fluid and best characterizes the properties of drilling fluid at low shear rates.

Since the data measured by the funnel viscosimeter are significantly influenced by colloidal content and density, which cause changes in the static pressure of the liquid column in the funnel, the viscosity data obtained with the funnel viscosimeter cannot be directly compared with data measured using a direct-reading viscosimeter due to these variations.

II. Models and Specifications

III. Main Technical Parameters of the Instrument