Hylok Frequently Asked Questions  

Q. Does the Hy-Lok tube fitting interchange and intermix with other two ferrule instrument tube fittings?
A. Yes. We have many, many satisfied customers intermixing with the recognized manufacturer names in the industry having excellent performance experience. Independent lab tests also prove interchanging can be done safely. International certification agencies, backed by independent testing approve the practice. We will be glad to discuss this issue with you in detail

Q. What is the pressure rating of the Hy-Lok tube fitting?

A. With proper installation and tube selection, Hy-Lok will easily hold leak tight without tube separation to the burst point of the tube. Since ASTM specifications require a 4:1 safety factor, the pressure rating of the fitting is determined by the working and burst pressure of the tube. Remember this is true ONLY if the fitting is installed properly per manufacturer's recommendations on tubing specified in the current Hy-Lok catalog. We will be happy to discuss this and other training issues.

Q. Why does Hy-Lok offer so many different configurations of small needle and instrument ball valves?
A. There are unlimited fluid system applications for small needle and ball valves. All of which involve different combinations of variables such as pressure, temperature, material compatibility, flow, structural strength, end connection, manual or automated, panel mount, cycle life, dead space and more. Because of this, the wide product offering is driven by customer demand. Our qualified technical staff with over 100 years of combined experience in instrument fluid system components can help you make the right decision.

Q. What determines the pressure rating of an instrument needle or ball valve?
A. Many competitors rate their products based solely on tensile strength and minimum wall thickness of the materials of construction. Hy-Lok also considers a reasonable cycle life when rating valve products. We have seen several competitive valves rated for high pressure and are strong enough to hold, until the valve has been actuated a few times resulting in seat and/or stem leakage. Seat material, surface finishes, and quality tolerance control are a few reasons why Hy-Lok performs so well.

Q. What does Cv stand for?
A. The Cv of a valve is its flow coefficient and represents the number of gallons of water that will flow through a valve, fully open, at room temperature, under 1 PSI pressure drop.

Q. I often hear the terms tube and pipe to describe the same thing, is there a difference?
A. Yes. Tubing sizes refer to outside diameter (O.D.). Pipe sizes refer to the inside diameter (I.D.). In other words, a 3/4" tube O.D. would mike .750" plus or minus .005". 3/4" pipe O.D. would mike about 1.050". There are many other differences. Ease of installation, fewer connections, easier to bend, higher strength to weight ratio, total installed costs, and ease of maintenance are just a few reasons why we feel tubing with Hy-Lok tube fittings are a better choice for small bore systems. There are many other advantages we would be glad to discuss with you.

Q. What is the largest size tube fitting Hy-Lok makes?
A. Hy-Lok tube fittings are available up to 2" O.D. Hy-Lok has an electric automatic swaging tool as well as a manual hydraulic swaging tool to install Hy-Lok fittings from 1/2" O.D. to 2" O.D.

Q. What tubing spec do you recommend I follow if I need 300 series stainless steel?
A. ASTM A269 or ASTM A213 are the most common and recommended for use with 316 Stainless Hy-Lok tube fittings.

Q. We know Hy-Lok sources much of its raw material from US specialty steel mills, so how does Hy-Lok offer such high quality products at such competitive pricing?
A. Hy-Lok manufactures products on modern "CNC" machine tools. These machines are capable of very high speeds and feed rates while maintaining exacting tolerance control. Computerization and SPC programs result in high productivity and high quality, resulting in lower total manufacturing cost.

Q. How is price and delivery of special parts?
The set-up time on the modern machines Hy-Lok uses is very quick. Specials are no problem. We have experienced postitive feedback from customers stating we regularly exceed our competitors' deliveries at a saving.