A vacuum booster assembly includes, but is not limited to, a booster housing defining a booster chamber and including a gas inlet and a gas outlet; a first rotor positioned within the booster chamber and adapted for rotation therein, the first rotor including a first shaft and at least two lobes defining a first lobe profile; and a second rotor positioned within the booster chamber and adapted for rotation therein, the second rotor including a second shaft and at least two lobes defining a second lobe profile, wherein the first and second rotors are formed from a metal having a coefficient of thermal expansion from about 1 (10.sup.−6 in/in*K) to about 13 (10.sup.−6 in/in*K), and wherein at least one of the outer surface of the first rotor, the outer surface of the second rotor, or the booster chamber includes a coating.

Rotors formed by an additive manufacturing process are presented. In one example, a method of making a rotor is presented including defining a printing order for the application of a first material, and creating a plurality of lobes arranged helically about a central opening or a shaft by adding a first material in the printing order, wherein each of the plurality of lobes defines an outer surface.

A vacuum booster assembly includes, but is not limited to, a booster housing defining a booster chamber and including a gas inlet and a gas outlet; a first rotor positioned within the booster chamber and adapted for rotation therein, the first rotor including a first shaft and at least two lobes defining a first lobe profile; and a second rotor positioned within the booster chamber and adapted for rotation therein, the second rotor including a second shaft and at least two lobes defining a second lobe profile, wherein the first and second rotors are formed from a metal having a coefficient of thermal expansion from about 1 (10.sup.-6 in/in * K) to about 13 (10.sup.-6 in/in * K), and wherein at least one of the outer surface of the first rotor, the outer surface of the second rotor, or the booster chamber includes a coating.

Rotors formed by an additive manufacturing process are presented. In one example, a method of making a rotor is presented including defining a printing order for the application of a first material, and creating a plurality of lobes arranged helically about a central opening or a shaft by adding a first material in the printing order, wherein each of the plurality of lobes defines an outer surface.

A vacuum booster assembly includes, but is not limited to, a booster housing defining a booster chamber and including a gas inlet and a gas outlet; a first rotor positioned within the booster chamber and adapted for rotation therein, the first rotor including a first shaft and at least two lobes defining a first lobe profile; and a second rotor positioned within the booster chamber and adapted for rotation therein, the second rotor including a second shaft and at least two lobes defining a second lobe profile, wherein the first and second rotors are formed from a metal having a coefficient of thermal expansion from about 1 (10.sup.−6 in/in*K) to about 13 (10.sup.−6 in/in*K), and wherein at least one of the outer surface of the first rotor, the outer surface of the second rotor, or the booster chamber includes a coating.

A method for producing a water-hydraulic machine having a first member (1) and a second member (2) in sliding contact with a contact surface (3) of the first member (1), wherein the second member (2) comprises a surface made of a friction reducing plastic material and the contact surface (3) is a metallic surface, is disclosed. The machine should have a low risk of damages. To this end, the method includes the steps of using a first member (1) comprising a first part (4) having the contact surface (3) and a second part (5), using a high temperature hardening process at a temperature of at least 1000 C. to give a deep surface hardening of the contact surface (3) of the first part (4), machining of the first part (4) to the desired geometry, assembling the first part (4) and the second part (5) to form the first member.

A reciprocating pump is disclosed. The reciprocating pump may comprise a power end, and a fluid end operatively connected to the power end. The fluid end may include a plunger, a cylinder configured to operatively engage the plunger, and an end block. The plunger, the cylinder, and the end block of the fluid end may each be fabricated from a high toughness martensitic stainless steel composition comprising between 11.50% and 17.00% by weight chromium, between 3.50% and 6.00% by weight nickel, between 0.30% and 1.50% by weight molybdenum, between 0.01% and 0.20% by weight vanadium, and iron.

A pumping mechanism is disclosed. The pumping mechanism may include a barrel formed of a barrel substrate and including a first end surface, a second end surface opposite the first end surface, and a bore between the first and second end surfaces. Each of the first and second end surfaces and the bore is coated with a metal plating. The pumping mechanism may further include a plunger formed of a plunger substrate and configured to be slidably disposed in the bore in barrel, the plunger substrate having a tribological coating.

Rotors formed by an additive manufacturing process are presented. In one example, a method of making a rotor is presented including defining a printing order for the application of a first material, and creating a plurality of lobes arranged helically about a central opening or a shaft by adding a first material in the printing order, wherein each of the plurality of lobes defines an outer surface.

A temperature-compensating arrangement is provided for a fluid-moving or fluid-powered rotating machine. One or more rotatable inner components in a housing of the machine are supported and restrained by at least one radial load bearing and allowed to float axially as a result of differences in thermal expansion of one or more inner components and the housing. The housing and inner component(s) are made from materials having coefficients of expansion selected to minimize undesired clearance changes and undesired bearing loads that are caused by the differences in thermal expansion of the materials during temperature changes of the machine.