A device (20) for measuring the flow rate of ink sent to a print head of an ink jet printer, comprising: a restriction (22) of the diameter of the flow of ink, arranged in the path thereof, sensors (26, 28) for measuring the pressure difference (P.sub.in−P.sub.out), between the pressure of fluid upstream of the restriction (P.sub.in) and the pressure of ink downstream of the restriction (P.sub.out).

In-line viscosity measurement systems and related methods may be useful in measuring the viscosity of a fluid in a flow path and, more specifically, in-line measuring the viscosity of a drilling fluid when integrated with drilling systems. For example, a method may include drilling a wellbore penetrating a subterranean formation while circulating a drilling fluid through the wellbore; measuring the viscosity of the drilling fluid with an in-line viscometer system after the drilling fluid has circulated through the wellbore, the in-line viscometer systems comprising either: (1) a two coaxial cylinder configuration, (2) a parallel plates configuration, or (3) a combination thereof positioned to allow for the drilling fluid to flow between the coaxial cylinders or parallel plates.

In-line viscosity measurement systems and related methods may be useful in measuring the viscosity of a fluid in a flow path and, more specifically, in-line measuring the viscosity of a drilling fluid when integrated with drilling systems. For example, a method may include drilling a wellbore penetrating a subterranean formation while circulating a drilling fluid through the wellbore; measuring the viscosity of the drilling fluid with an in-line viscometer system after the drilling fluid has circulated through the wellbore, the in-line viscometer systems comprising either: (1) a two coaxial cylinder configuration, (2) a parallel plates configuration, or (3) a combination thereof positioned to allow for the drilling fluid to flow between the coaxial cylinders or parallel plates.

A method and an apparatus manufactures and tests workpieces. The apparatus is mountable on or includes a system for mixing or melting materials. The apparatus includes application units and a replacement system that is designed to automatically replace application units in respect of the position or function thereof.

A method and an apparatus manufactures and tests workpieces. The apparatus is mountable on or includes a system for mixing or melting materials. The apparatus includes application units and a replacement system that is designed to automatically replace application units in respect of the position or function thereof.

Methods for preform and tube draw based on controlling forming zone viscosity determined by calculating a holding force exerted by the glass component in the forming zone on the strand being drawn below. The holding force may be calculated by determining a gravitational force applied to the strand and a pulling force applied to the strand by a pulling device, where the holding force is equal to the opposite of the algebraic sum of the gravitational and pulling forces. The holding force may also be calculated by measuring a stress-induced birefringence in the strand at a point between the forming zone and the pulling device, determining an amount of force applied to the strand at the point corresponding to the birefringence, and calculating the holding force by correcting the amount of force for a gravitational effect of the weight of the strand between the forming zone and the point.

Methods for preform and tube draw based on controlling forming zone viscosity determined by calculating a holding force exerted by the glass component in the forming zone on the strand being drawn below. The holding force may be calculated by determining a gravitational force applied to the strand and a pulling force applied to the strand by a pulling device, where the holding force is equal to the opposite of the algebraic sum of the gravitational and pulling forces. The holding force may also be calculated by measuring a stress-induced birefringence in the strand at a point between the forming zone and the pulling device, determining an amount of force applied to the strand at the point corresponding to the birefringence, and calculating the holding force by correcting the amount of force for a gravitational effect of the weight of the strand between the forming zone and the point.

Evaluating surfactants for use in downhole applications, especially surfactants with similar surface tension or interfacial tension values and wetting properties, may be achieved with a sensitive column test using a non-uniform particulate media therein. An exemplary method may include providing a column containing two types of particles that differ by at least one of: a mean particle diameter, a sphericity, and a chemical composition. Surfactant samples may be individually tested by passing the sample through the column followed by a displacement fluid, typically an oleaginous. The displacement rate and volume of the surfactant sample may be used to assess the surfactant's suitability for downhole applications.

Evaluating surfactants for use in downhole applications, especially surfactants with similar surface tension or interfacial tension values and wetting properties, may be achieved with a sensitive column test using a non-uniform particulate media therein. An exemplary method may include providing a column containing two types of particles that differ by at least one of: a mean particle diameter, a sphericity, and a chemical composition. Surfactant samples may be individually tested by passing the sample through the column followed by a displacement fluid, typically an oleaginous. The displacement rate and volume of the surfactant sample may be used to assess the surfactant's suitability for downhole applications.

A capillary bridge viscometer, comprises an input port (flow in) an output port (flow out) a first capillary tubing arm (R1) in a first hydraulic path between the input port and a first differential detection point (DP+), a second capillary tubing arm (R3) in a second hydraulic path between the first differential detection point (DP+) and the output port (flow out), a third capillary tubing arm (R2) in a third hydraulic path between the input port (flow in) and a second differential detection point (DP−), a fourth capillary tubing arm (R4) in a fourth hydraulic path between the second differential detection point (DP−) and the output port (flow out), an adjustable mechanical flow restrictor (20) in one of the first, second, third, and fourth hydraulic paths, wherein the adjustable mechanical flow restrictor (20) is operative to mechanically adjust a resistance to flow of a fluid while the fluid flows through the adjustable mechanical flow restrictor.