What is the Difference Between RTJ and RF Flanges?
RF (raised face) flanges are sealed with a flat gasket. The raised faces are precision machined with a serrated spiral finish, 125-250 AARH. The texturized faces increase the strength and retaining force of the connection made to the gasket.
RTJ (ring type joint) flanges have grooves machined into their faces. These grooves are made to accept Ring Gaskets. During installation the bolts are tightened on the flanges. Tightening of the bolts causes the gasket to press into groove creating a metal to metal seal.
Please note that different RTJ/RF styles and sealing methods exist and can vary from manufacturer to manufacturer.
Are Hammer Unions Bi-Directional?
Yes, hammer unions are in fact bi-directional. Other products that have hammer union connections such as swivel joints, crossovers and hose loops are also bi-directional. The direction of flow is based on user preference.
However, if lines are in a vertical direction it is recommended that the male half is faced in the downward position. This ensures that the lug nut/wing nut will remain in place on the male sub while the hammer union is disconnected.
How to Identify Male and Female Hammer Union Parts
Ordering Hammer Union parts, Crossovers, or Integral Fittings can be complicated at times. Sometimes there is confusion when trying to identify which connection your customer needs. This confusion often leads to returns and exchanges.
In the field, especially on the industrial side, the connection with the ACME threads is typically referred to as the Male Half/Male Sub. However, it is just the opposite. The diagram below will help you and your customer distinguish which part is needed. When purchasing Hammer Union parts from C&C please be sure to indicate exactly which parts are needed. C&C does not sell Hammer Union Halves; rather we sell individual parts (i.e. Female Sub, Male Sub, Nut/Lug Nut, Snap Ring, Segments, etc) and complete Hammer Unions.
Why are the ACME Threads Partially Exposed on 2″ Figure 602 Hammer Unions?
In the past there has been a history of safety concerns surrounding the misidentification and inadvertent mismatching of 2″ Figure 602 hammer unions with 2″ Figure 1502 hammer unions. When a 2″ Figure 602 female sub is screwed into a 2″ 1502 nut, the combination may hold pressure for a short time but it will ultimately fail. Unfortunately this mistake has caused property damage and injuries in the past.
In an effort to prevent this from occurring in the future, many industry leading manufacturers, including C&C Industries, have adopted a new design for the 2″ Figure 602 female sub. This design will not allow the 2″ Figure 602 female to be made up to the 2″ Figure 1502 nut. If an end user tries to mate the two hammer unions, they will immediately notice that the threads on the female sub do not engage the threads on the nut.
Careful attention was taken to ensure that the new design is reverse compatible. The male sub and nut of the 2″ Figure 602 Hammer Union have not been altered in any way, so if there are old parts in your inventory or in the field, they will still mate up with the new female sub if necessary.
You may notice that the hammer union looks visually different, particularly that the acme threads on the female sub may remain partially exposed even when the hammer union is fully hammered together. However, this is normal, and does not affect the sealing properties of the hammer union in any way.
We appreciate your continued support of C & C products, and as always, we will be happy to address any comments or concerns you may have about this change.
What is the Pressure Rating for Swages & Bull Plugs?
This is a common question. However, Swage Nipples and Bull Plugs do not have published pressure ratings. Common practice is to use the same schedule (i.e. 40, 80, etc) that is being used on the A106 pipe. Ask the customer which schedule pipe is being used. Then be sure to order that same schedule for the Swages or Bull Plugs.
Available schedules are:
- 40 (Standard, Std.)
- 80 (Extra Heavy, XH)
- XXH (Double Extra Heavy)
Letter from our QA Department:
C&C has received many requests from distributors and users to publish a pressure rating for our line of Swage Nipples and Bull Plugs. We have elected not do so because we cannot reasonably anticipate what design code needs to be used. Each design code (ASME, EN, API, Etc.) utilizes various factors of safety based on different design variables. For example if C&C were to publish a pressure rating based on the design rules from ASME Boiler and Pressure Vessel Code Sec. VIII Div. 1, that pressure rating may not be consistent with the pressure rating for the same swage nipple instaled in an ASME B31.3 piping system. Some manufacturers have chosen to publish estimated pressure ratings using an arbitrary safety factor, however we feel this is not good practice. In order to select the proper swage nipple or bull plug, the user should follow these guidelines:
1. Determine the wall thickness and the material grade (or minimum yield strength) of the piping that the bull plug will be affixed to. In the case of a swage nipple determine the wall thickness and the grade (or minimum yield strength) of the piping that will be affixed to the largest side of the swage nipple.
2. Select a swage nipple or bull plug that has an equivalent or greater wall thickness and matches either he material grade or meets the minimum allowable yield strength of the piping to which the fitting will be connected.
3. If minimum yield strength is used to determine compatibility, the user should note that the swage/bull plug and piping should be made from a similar type of material. (e.g. a carbon steel swage should not be affixed to a string of stainless steel pipe)
4. Select an end connection that is consistent with the end connections throughout the rest of the system. We understand the confusion caused by not publishing a pressure rating for our swage nipples and bull plugs, however we hope this letter will help users and distributors to understand why we are unable to provide this
What is an OS&Y Gate Valve?
OS&Y (outside screw & yoke) gate valves are different from traditional gate valves. OS&Y valves operate by opening and closing through a wedge/gate. Both the screw and wedge lower in and out of the gate valve thus opening and closing it. When the gate valve is in the open position the stem rises. When the gate valve is in the closed position the stem is lowered. This feature allows operators to visually inspect the valve and know whether it is open or closed. With traditional style gate valves visual inspection will not determine if the gate valve is open or closed.
What is a Plug Valve?
Plug valves have cylindrical or tapered “plugs”. The plugs can be turned inside the valve body in order to control flow through the valve. Plug valves typically have one or more hollow access points that allow the media to flow through the valve with ease when in the open position.
There are various types of plug valves and they generally fall into four categories. At C&C, we offer a lubricated plug valve. Lubricated plug valves require special oil or grease in order to seal. It is recommended that the lubricant be suitable for the process fluid being used.
C&C LT Plug Valves are a quarter turn valve with a lubricated and tapered seal. Quarter turn plug valves are optimal when quick and frequent operation is needed. Our plug valves are an ideal choice for high pressure and abrasive conditions.
C&C LT Plug Valves are traditionally used in the oil and gas industry and usually seen in flowback, fracking, cementing, and well-servicing applications.