Driven-capillary viscosimeter

Differential pressure viscosimeter for measuring the viscosity of a fluid, comprising

• a hollow pressure cylinder having first and second ends and an interior wall, the cylinder including means for receiving a fill of said fluid for measuring its viscosity;
• a piston disposed for axial movement in said cylinder and sealably contacting the interior wall thereof, including a capillary passage extending axially through said piston to permit passage of said fluid through said passage;
• a drive shaft connected to said piston and extending through the first end of said cylinder;
• a drive assembly coupled to said drive shaft and fixedly mounted relative to said cylinder for driving said piston axially in said cylinder, said drive assembly including a frame, bracket means mounting said cylinder relative to said frame, a controllable electric motor having an axle, a tachometer mounted on said axle and providing signal indicative of the speed of the motor axle, a jack driven by said motor axle translating rotational motion of said axle into linear motion for driving said drive shaft, and control means for controlling the current to said motor in response to said signal;
• and
• pressure monitoring means disposed in fluid communication with the interior of said cylinder for measuring the pressure differential in said fluid across said capillary passage while said piston is being driven.

Differential pressure viscosimeter for measuring the viscosity of a fluid, comprising

• a hollow pressure cylinder having first and second ends and an interior wall, the cylinder including means for receiving a fill of said fluid for measuring its viscosity;
• a piston disposed for axial movement in said cylinder and sealably contacting the interior wall thereof, the piston including a capillary passage extending axially through said piston to permit passage of said fluid through said passage;
• drive means coupled to said piston for driving said piston axially relative to said cylinder, so that the fluid in said cylinder is displaced through said passage;
• oven enclosure means for enclosing the cylinder, the latter being mounted therewithin, to maintain said cylinder at a temperature representative of the natural conditions of said fluid;
• and
• pressure monitoring means disposed in fluid communication with the interior of said cylinder for measuring the pressure differential in said fluid across said capillary passage while said piston is being driven.

Differential pressure viscosimeter for measuring the viscosity of a fluid, comprising

• a hollow pressure cylinder having first and second ends and an interior wall, the cylinder including means for receiving a fill of said fluid for measuring its viscosity;
• a piston disposed for axial movement in said cylinder and sealably contacting the interior wall thereof, the piston including main piston body having a plurality of capillary passages disposed circumferentially about the axis of said piston and each extending axially through said main piston body, said piston further including a selector plate having an aperture therethrough and alignable with a selected one of said capillary passages to permit flow of said fluid through and only through the selected passage;
• means for driving said piston at a controlled speed axially within said cylinder so that said fluid is displaced through said selected capillary passage;
• selecting means extending external to said cylinder for selectively rotating said selector plate relative to said main piston body to select a desired one of said capillary passages;
• and
• pressure monitoring means disposed in fluid communication with the interior of said cylinder for measuring the pressure differential in said fluid across the selected capillary passage while said piston is being driven.

Differential pressure viscosimeter for measuring the viscosity of a fluid, comprising

• a hollow pressure cylinder having first and second ends and an interior wall, the cylinder including means for receiving a fill of said fluid for measuring its viscosity;
• a piston disposed for axial movement in said cylinder and sealably contacting the interior wall thereof, the piston including a main piston body having a plurality of capillary passages disposed circumferentially about the axis of said piston and each extending axially through said main piston body, said piston further including a selector plate having an aperture therethrough alignable with a selected one of said capillary passages to permit flow of said fluid through and only through the selected passage;
• a drive shaft connected to one of said main piston body and said selector plate and extending through the first end of said cylinder;
• a drive assembly coupled to said drive shaft and fixedly mounted relative to said cylinder for driving said piston axially in said cylinder;
• a selector shaft affixed to the other of said main piston body and said selector plate and extending out from the second end of said cylinder;
• selector means on said selector shaft for rotating the same to effect mutual rotation of said main piston body with said selector plate for selectively aligning said aperture with a desired one of said capillary passages;
• and
• pressure monitoring means disposed in communication with the fluid at the first and second ends of said cylinder for measuring the pressure differential in said fluid across the selected capillary passage while said piston is being driven.

Differential pressure viscosimeter for measuring the viscosity of a fluid, comprising

• a hollow pressure cylinder having first and second ends and an interior wall, the cylinder including means for receiving a fill of said fluid for measuring its viscosity;
• a piston disposed for axial movement in said cylinder and sealably contacting the interior wall thereof, the piston including a main piston body having eight capillary tubes, each having a passage of a different radius, spaced circumferentially 45.degree. apart about the axis of said piston and each extending axially through said main piston body, said piston further including a selector plate having an aperture therethrough alignable with a selected one of said capillary passages to permit passage of said fluid through and only through the selected passage;
• a drive shaft connected to one of said main piston body and said selector plate and extending through the first end of said cylinder;
• a drive assembly coupled to said drive shaft and fixedly mounted relative to said cylinder for driving said piston axially in said cylinder;
• a selector shaft affixed to the other of said main piston body and said selector plate and extending out from the second end of said cylinder;
• a selector device coupled to said selector shaft for rotating the same to effect mutual rotation of said main piston body with said selector plate for selectively aligning said aperture with a desired one of said capillary passages;
• and
• pressure monitoring means disposed in communication with the first and second ends of said cylinder for measuring the pressure differential in said fluid across the selected capillary passage while said piston is being driven.

Differential pressure viscosimeter for measuring the viscosity of a fluid, comprising

• a hollow pressure cylinder having first and second ends and an interior wall, the cylinder including means for receiving a fill of said fluid for measuring its viscosity;
• a piston disposed for axial movement in said cylinder and sealably contacting the interior wall thereof, the piston including a main piston body having a plurality of capillary passages disposed circumferentially about the axis of said piston and each extending axially through said main piston body, said piston further including a selector plate having an aperture therethrough selectively alignable with said capillary passages to permit passage of said fluid through and only through the selected passage;
• a drive shaft connected to one of said main piston body and said selector plate and extending through the first end of said cylinder;
• a drive assembly coupled to said drive shaft and fixedly mounted relative to said cylinder for driving said piston axially in said cylinder, said drive assembly including a frame, bracket means mounting said cylinder relative to said frame, a controllable electric motor having an axle, a tachometer mounted on said axle and providing a signal indicative of the speed of the motor axle, a jack driven by said motor axle for driving said drive shaft axially, and control means for controlling the current to said motor in response to said signal;
• a selector shaft affixed to the other of said main piston body and said selector plate and extending out from the second end of said cylinder;
• a selector handle on said selector shaft for rotating the same to effect mutual rotation of said main piston body with said selector plate for selectively aligning said aperture with a desired one of said capillary passages;
• and
• pressure monitoring means disposed in fluid communication with the interior of said cylinder for measuring the pressure differential in said fluid across the selected capillary passage while said piston is being driven.

Differential pressure viscosimeter for measuring the viscosity of a fluid, comprising

• a hollow pressure cylinder having first and second ends and an interior wall, the cylinder including means for receiving a fill of said fluid for measuring its viscosity;
• a piston disposed for axial movement in said cylinder and sealably contacting the interior wall thereof, the piston including a main piston body having a plurality of capillary passages disposed circumferentially about the axis of said piston and each extending axially through said main piston body said piston further including a selector plate having an aperture therethrough alignable with a selected one of said capillary passages to permit passage of said fluid through and only through the selected passage;
• a drive shaft connected to one of said main piston body and said selector plate and extending through the first end of said cylinder;
• a drive assembly coupled to said drive shaft and fixedly mounted relative to said cylinder for driving said piston axially in said cylinder;
• a selector shaft affixed to the other of said main piston body and said selector plate and extending out from the second end of said cylinder;
• an oven enclosure having side walls, a first end wall, and a second end wall, the oven enclosure enclosing the cylinder, with the latter being fixedly mounted therewithin, to maintain said cylinder at a temperature representative of the natural conditions of said fluid;
• said drive assembly being mounted at said first end wall with said drive shaft passing therethrough, said selector shaft passing through said second end wall;
• a selector device on said selector shaft situated outside said oven enclosure for rotating the same to effect mutual rotation of said main piston body and said selector plate for selectively aligning said aperture with a desired one of said capillary passages;
• and
• pressure monitoring means disposed at said first and second ends of said cylinder for measuring the pressure differential in said fluid across the selected capillary passage while said piston is being driven.